Volume 4 (2006)
  Special Issue

Contents


Pages

v345-348 M. Samuitienė and M. Navalinskienė
Molecular detection and characterization of phytoplasma infecting Celosia argentea L. plants in Lithuania
Abstract |
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Molecular detection and characterization of phytoplasma infecting Celosia argentea L. plants in Lithuania

M. Samuitienė and M. Navalinskienė

Institute of Botany, Žaliųjų Ežerų 49, Vilnius LT-08406, Lithuania;e-mail: msamuit@botanika.lt

Abstract:

Symptoms of diseased Celosia argentea L. plants included flower phyllody, general yellowing and stunting of plants. Amplification of phytoplasmal 16S rRNA gene sequence, in PCRs containing phytoplasma universal primer pairs P1/P7, R16F2n/R16R2 and template DNA extracted from diseased C. argentea plants, confirmed that the plants were infected by phytoplasma. The 1.2 kbp 16S rDNA product of nested PCR, primed by primer pair R16F2n/R16R2 was subjected to single enzyme digestions with 8 restriction endonucleases. RFLP analysis revealed that the plants were infected by a phytoplasma belonging to group 16SrI (aster yellows phytoplasma group), subgroup I–M. Strains in this subgroup have a broad pathogenic potential, since they infect a wide range of plant host species.

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121-128 A.A. Amin and M.F. Gergis
Integrated management strategies for control of cotton key pests in Middle Egypt
Abstract |

Integrated management strategies for control of cotton key pests in Middle Egypt

A.A. Amin and M.F. Gergis

Plant Protection Research Institute, ARC, MOA 7, Nady El-Sayied Street, Dokki,Giza 12311, Egypt; e-mail: aahakaa@yahoo.com

Abstract:

In cotton production, there are many factors that can reduce crop yield. One important cause is insects. Insects that cause loss to the fruit are frequently more destructive than those that damage leaves, stems and roots. Cotton in Egypt is subjected to yield and quality losses by arthropod insects; losses extend to oil contents in the seeds. The cotton leaf worm (CLW), Spodoptera littoralis, the pink bollworm (cotton bollworm) (PBW), Pectinophora gossypiella and spiny bollworm (SBW), Earias insulana cause the greatest number of yield losses from nearly one million hectares cultivated annually.This study describes an improvement in insect control practices directed against feedinginsects (i.e., CLW, PBW and SBW) by integration of monitoring, biological control, cultural, behavioural and genetic aspects, and bio-insecticides that can serve as a basis for the formulation of a biologically-based new approach of integrated management of key cotton pests. Field studies were conducted during 2004 and 2005 at Minia Governorate, Middle Egypt. The experimental area was about 150 hectares of cotton (Giza-80). Five programs were evaluated. Percentages of infestations, cotton yield and population density of both natural enemies and sucking pests were used as criteria for evaluation of various programs.

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129-132 O. Auškalnienė and A. Auškalnis
Effect of sulfonylurea herbicides on weeds and maize
Abstract |

Effect of sulfonylurea herbicides on weeds and maize

O. Auškalnienė and A. Auškalnis

Lithuanian Institute of Agriculture, Instituto aleja 1 Akademija, LT-58344 - Kedainiai distr.,Lithuania; e-mail: ona@lzi.lt, albinas@lzi.lt

Abstract:

Three field experiments, designed to test the new sulfonylurea group herbicides, were conducted in maize crops during 2002–2003 at the Lithuanian Institute of Agriculture in Central Lithuania.The weed species differed between fields. The most frequent weed species in maize standswere Elytrigia repens, and Chenopodium album. The efficacy of tested herbicides against Chenopodium album, Echinocloa crus – galli differed in relation to active ingredients. Rimsulfuron-methyl and nicosulfuron-methyl were effective against Echinochloa crus – galli; primisulfuron-methyl did not have any effect on this weed species. Nicosulfuron – methyl and primisulfuron-methyl were effective against Chenopodium album, however, rimisulfuron methyl did not control that weed as effectively.The green matter yield of maize in treated plots was 1–18.4 t ha-1 higher than in theuntreated.

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133-136 A. Auskalnis and A. Kadzys
Effect of timing and dosage in herbicide application on weed biomass in spring wheat
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Effect of timing and dosage in herbicide application on weed biomass in spring wheat

A. Auskalnis and A. Kadzys

Lithuanian Institute of Agriculture, Instituto aleja 1, Akademija,58344- Kedainiai distr.Lithuania; e-mail: albinas@lzi.lt

Abstract:

The biological efficacy of herbicide Mustang (a.i. florasulam +2.4 D ester 6.25+452.5 g l-1) applied at doses 0.6, 0.45, 0.3 and 0.15 l ha-1 as compared to untreated areas was evaluated on the number and biomass of weeds in spring wheat in field trials at the Lithuanian Institute of Agriculture in 2003–2005. Herbicide was applied at the 3- leaf stage, at tilling, and at the beginning of stem elongation of cereals.The best efficacy on weed mass in all years of the experiments was achieved when theherbicide was applied at the 3-leaf stage and during the tilling stage of spring wheat. The weed biomass decreased by 82 to 92% in 2003 and 2004 and by 74–96% in 2005, from 0.3, 0.45 and 0.6 l ha-1 doses. When herbicides were applied using higher doses, 0.45-0.6 l ha-1.,during the spring wheat stem elongation stage (BBCH 31-32), the biomass of weeds decreased by 75–95%. When the lowest dose, 0.15 l ha-1 of the herbicide Mustang was applied at the beginning of the stem elongation stage of spring wheat, the efficacy on the total fresh mass of weeds was insufficient.

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137-140 I. Brazauskiene and E. Petraitiene
Epidemiological studies into Phoma lingam (teleomorph Leptosphaeria maculans) infections in winter and spring oilseed rape
Abstract |
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Epidemiological studies into Phoma lingam (teleomorph Leptosphaeria maculans) infections in winter and spring oilseed rape

I. Brazauskiene and E. Petraitiene

Lithuanian Institute of Agriculture, Department of Plant Pathology and Protection,Instituto alėja 1, Akademija, Kėdainiai distr. LT 58344, Lithuania;e-mail: brazausk@lzi.lt; egle@lzi.lt

Abstract:

Studies of the concentration of ascospores of Leptosphaeria maculans (anamorph Phoma lingam) in the air, appearance and variation of visual symptoms of phoma stem canker during the growing season of oilseed rape in relation to the main meteorological indicators were carried out. Spore samples, collected over 200 days in 2004 and 2005 using a Burkard spore trap, were analyzed using the method of microscopy. The first ascospores of Leptosphaeria maculans were found in the samples from 1 May 2004 and 9 April 2005. The abundance of ascospores in the air depended on the weather factors, especially the amount and frequency of precipitation. The first symptoms of phoma on the leaves of winter oilseed rape in 2004 were recorded at the end of October, and in 2005, in the spring crop on 3 May, i.e. three weeks later, after the first ascospores had been identified in the air. On 7 June 7 2005 the first symptoms of phoma stem canker were identified on stems of winter oilseed rape. Spring oilseed rape was more tolerant of phoma stem canker, compared with winter oilseed rape. At the end of maturity stage (BBCH 85), 83.2–81.0% of winter oilseed rape and 35.2–28.6% of spring oilseed rape stems with phoma stem canker symptoms were found in 2004 and 2005, respectively. Diseased stems of winter oilseed rape exhibited mostly double phoma symptoms – on the crown and on the stem 5 cm above the crown (78.4% in 2004 and up to 65% of diseased stems in 2005). Diseased stems of spring oilseed rape mainly displayed phoma symptoms 5cm above the crown (69.2–98.7%).

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141-146 V. Būda, Ž. Lukšienė, S. Radžiutė N. Kurilčik and S. Juršėnas
Search for photoinsecticides: effect of hematoporphyrin dimethyl ether on leafmining pest Liriomyza bryoniae (Diptera: Agromyzidae)
Abstract |
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Search for photoinsecticides: effect of hematoporphyrin dimethyl ether on leafmining pest Liriomyza bryoniae (Diptera: Agromyzidae)

V. Būda¹, Ž. Lukšienė², S. Radžiutė¹ N. Kurilčik² and S. Juršėnas²

¹Institute of Ecology, Vilnius University, Akademijos 2, Vilnius-21, LT-08412,Lithuania; e-mail: vinbuda@ekoi.lt
²Institute of Materials Science and Applied research, Vilnius University, Saulėtekio 9,Vilnius, LT-10223, Lithuania; e-mail: zivile.luksiene@mtmi.vu.lt

Abstract:

Photoactive compounds might be used as effective pesticide agents, with almost no impact on the environment, being nontoxic and not mutagenic. The point is, that nontoxic photoactive compound accumulates within the insect body and, following exposition to visible light, induces lethal photochemical reactions and death of target pest. The aim of this study was to determine, whether hematoporphyrin dimethyl ether (HPde) might be effective as photoinsecticide. Leafmining fly Liriomyza bryoniae (Diptera, Agromyzidae) was selected as the target species. Results obtained indicate, that exposition of insects to the bait, containing HPde and following irradiation with visible light resulted in total killing of Liriomyza bryoniae adults. Moreover, survival of insects, exposed to the bait, containing HPde and irradiated with visible light depended on sex: females were more sensitive to photosensitization compare to males. Females survived less than 1 day after the treatment and males survived up to 3 days. We assume this was predetermined by difference in feeding intensity.

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147-150 V. Bulovienė and E. Survilienė
Effect of environmental conditions and inocolum concentration on sporulation of Peronospora destructor
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Effect of environmental conditions and inocolum concentration on sporulation of Peronospora destructor

V. Bulovienė and E. Survilienė

Lithuanian Institute of Horticulture, Kauno str. 30, LT - 54333 Babtai, Kaunas distr.,Lithuania; e-mail: v.bandzeviciute@lsdi.lt

Abstract:

The effect of inoculum concentration, incubation time, relative humidity (RH) and temperature on sporulation of Peronospora destructor on onion leaves was analyzed under controlled environmental conditions in a greenhouse. The shortest period for spore germination and sporulation was on onion leaves inoculated with 106 spores/ml distilled water suspension. The intensity of infection and the sporulation of infected plants were affected greatly by the time and temperature of incubation. Exposure of inoculated plants at 15°C for 8 days and then at 22°C for 5 days resulted in the percentage of infection and the most abundant sporulation. Results of this experiment indicated that the period of P. destructor sporulation on one plant lasted 4–8 days.

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151-154 D. Burokienė
Early detection of Clavibacter michiganensis subsp. Michiganensi in tomato seedlings
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Early detection of Clavibacter michiganensis subsp. Michiganensi in tomato seedlings

D. Burokienė

Institute of Botany, Žaliųjų Ežerų g. 49, LT-08406 Vilnius, Lithuania;e-mail: daiva@botanika.lt

Abstract:

The investigations of Clavibacter michiganensis subsp. Michiganensi in tomato seedlings were carried out using the BIO-PCR method. One to two (1–2) colonies were already detectable with species-specific primers CMM5 and CMM6 using Clavibacter michiganensis subsp. michiganensis bacteria in plant seedlings. The method allowed detection of bacteria at a distance of 8 cm farthest from the inoculation site in 95% of samples 3 days after treatment, at the earliest. Plant seedlings approximately 40 cm high were infected at full length after 9 days. Experimental results indicated the possibility of detecting the pathogen in very early stages of infection. Therefore, the BIO-PCR method was a highly specific, rapid and reliable detection technique, which might help to control the spread of the pathogen to healthy tomato plants.

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155-158 L. Buskienė, N. Uselis and J. Lanauskas
Possibilities of weed control with herbicide Basta 150 SL in a young apple tree orchard
Abstract |
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Possibilities of weed control with herbicide Basta 150 SL in a young apple tree orchard

L. Buskienė¹, N. Uselis² and J. Lanauskas²

¹Lithuanian Institute of Horticulture, Kauno 30, LT–54333 Babtai, Kaunas distr., Lithuania;e–mail: l.buskiene@lsdi.lt
²Lithuanian Institute of Horticulture, Kauno 30, LT–54333 Babtai, Kaunas distr., Lithuania;e–mail: institutas@lsdi.lt

Abstract:

The effect of herbicide Basta 150 SL (a.i. ammonium glufosinate) on weed control in a 3–4 year–old apple tree orchard was investigated at the Lithuanian Institute of Horticulture in 2004–2005. Basta 150 SL was applied at the rates 3.0 l ha-1 and 6.0 l ha-1, standard herbicide Roundup 360 SL – at the rate 3.0 l ha-1. Herbicides were applied twice over the growing season: the first application, until beginning of flowering, the second , when weeds had grown to 10–15 cm. Control plots were not treated with herbicides. Apple tree growth, weed species composition, weed number and weed fresh weight were measured.The most effective for weed control were 6.0 l ha-1 of Basta 150 SL and 3.0 l ha-1 ofRoundup 360 SL. They killed respectively 80.4–95.3% and 84.7–87.7% of weeds. Dandelions, (Taraxacum officinale L.), the prevailing weeds , were killed successfully with both herbicides. The lowest weed fresh weight was after 6.0 l ha-1 of Basta 150 SL application – 3.2%. Phytotoxic effect of herbicide Basta 150 SL on apple trees was not observed. When herbicides were applied apple tree shoot length increased by 1.4–1.9 times. Weed fresh weight had higher impact on shoot length than the total number of weeds.

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159-162 I. Deveikyte and V. Seibutis
Broadleaf weeds and sugar beet response to phenmedipham, desmedipham, ethofumesate and triflusulfuron-methyl
Abstract |

Broadleaf weeds and sugar beet response to phenmedipham, desmedipham, ethofumesate and triflusulfuron-methyl

I. Deveikyte and V. Seibutis

Lithuanian Institute of Agriculture, Department of Soil and Crop management, Instituto aleja 1,Akademija, Kedainiai distr., LT-58344, Lithuania; e-mail: irenad@lzi.lt, vytautas@lzi.lt

Abstract:

The sugar beet plant is a poor competitor against weeds. Uncontrolled weeds that emerge with the crop typically cause from 50 to 100% yield loss. Field studies were conducted from 2002-2004 to investigate the effects of different rates (1/1, ¾, ½) of herbicides on broadleaf weed control and yield of sugar beet. Phenmedipham + desmedipham + ethofumesate, triflusulfuron, metamitron, chloridazon, chloridazon + quimerac and oil-seed rape oil (1.0 l ha-1) were applied three times at 10 to 15 days intervals starting at the cotyledon growth stage of weeds at 91+71+112, 15, 700, 650, 540+90 g a.i. ha-1 dosage (full rate). All rates of herbicides phenmedipham + desmedipham + ethofumesate had a low efficacy. The addition of triflusulfuron to this herbicide reduced the amount of Tripleurospermum perforatum, Thlaspi arvense, Viola arvensis and Polygonum aviculare, but didn’t affect Chenopodium album, Lamium purpureum. Weed control by applying phenmedipham, desmedipham, ethofumesate and triflusulfuron had increased from 5.5 to 58% by the addition of metamitron, chloridazon and chloridazon+quimerac. The dry-weight of weeds varied significantly depending on the herbicide rates used. Using ½ of full (1/1) rates of the herbicide phenmedipham + desmedipham + ethofumesate had a low efficacy. All herbicide treatments produced higher sugar beet root and sugar yields than did phenmedipham + desmedipham + ethofumesate. Non-sugars were not affected by the herbicide treatments.

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163-166 L. Duchovskienė
The abundance and population dynamics of onion thrips (Thrips tabaci Lind.) in leek under field conditions
Abstract |
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The abundance and population dynamics of onion thrips (Thrips tabaci Lind.) in leek under field conditions

L. Duchovskienė

Lithuanian Institute of Horticulture, Laboratory of Plant Protection, LT-54333 Babtai,Kaunas distr., Lithuania, e-mail: l.raudonis@lsdi.lt

Abstract:

In 2003–2005 an abundance of onion thrips (Thrips tabaci Lind.) was investigated in two leek varieties – ‘American flag’ and ‘Campus’- at the Lithuanian Institute of Horticulture. Leeks were damaged by onion thrips every year, but only in 2005 were 100% of the plants infested. In 2003, there were on average 2.2 and 4.2 thrips per plant in ‘American flag’ and ‘Campus’ respectively. Intensity of thrips injury (according to 0–5 points scale) ranged from 1.5 to 1.7 points at the end of the season. Similar patterns were recorded in 2004. In 2005 the mean number of thrips was 13.2 and 13.0 per plant in ‘American flag’ and ‘Campus’ leek cultivars respectively. Intensity of injury at the end of the growing season ranged from 3.4 to 3.0 points. The highest abundance of onion thrips was in late July and early August 2004–2005. Only in 2003 was the maximum number of thrips reached in ‘Campus’ in September. There were no significant differences in the number of thrips between ‘American flag’ and ‘Campus’ leek cultivars. Low and medium correlation between the number of thrips and the incidence of purple blotch (Alternaria porri) at the beginning of infestation was found .

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167-170 V. Eremeev, A. Lõhmus and J. Jõudu
NegFry – DSS for the chemical control of potato late blight – results of validation trails in Tartu
Abstract |

NegFry – DSS for the chemical control of potato late blight – results of validation trails in Tartu

V. Eremeev, A. Lõhmus and J. Jõudu

Institute of Agricultural and Environmental Science (IAES), Estonian University of LifeScience, Kreutzwaldi St. 64, EE51014 Tartu, Estonia; e-mail: Viacheslav.Eremeev@emu.ee

Abstract:

Potato late blight, caused by the oomycete fungus Phytophthora infestans (Mont.) de Bary is the most destructive disease affecting the potato worldwide. For controlling the disease, most manuals recommend that growers apply fungicides at regular intervals of 8–10 days from the time of row closing until the end of the growing season. The NegFry model was used for timing the chemical control of potato late blight. The NegFry model is based on two existing models, the ‘negative prognosis’, for forecasting the risk of primary attacks, and a model for timing subsequent fungicide applications during the season. The main objective of NegFry is to get high yield and quality with minimum use of fungicides.Present work underscores that NegFry has given a positive result by timing the firstspraying for anticipation of the infection and by optimizing the number of treatments for late blight control.

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171-175 E.L. Gasich and A.O. Berestetskiy
Studies on soil application of Stagonospora cirsii, a candidate for biological control of Cirsium arvense
Abstract |

Studies on soil application of Stagonospora cirsii, a candidate for biological control of Cirsium arvense

E.L. Gasich and A.O. Berestetskiy

All-Russian Institute of Plant Protection RAS, shosse Podbelskogo 3, 196608 Pushkin,St.-Petersburg, Russia; e-mail: elena_gasich@mail.ru

Abstract:

Stagonospora cirsii, a causal agent of Canada thistle (Cirsium arvense) leaf spot, is under development as a biological control agent for this perennial noxious weed. S. cirsii had impact as a foliar spray and it proved highly pathogenic if applied at soil surface. Since Canada thistle is a perennial weed with a very vigorous root system, the ability of fungus to survive in soil and infect roots would greatly improve its potential as a mycoherbicide. Research was conducted to study the S. cirsii population dynamics in sterile soil, on the possibility of infecting Canada thistle creeping roots ed with the fungus, and its ablity to survive after being incorporated into/on the soil after over-wintering. The population dynamic was studied by dilution technique. In our experiments we used 10 g and 400 g of sterile field sod-podsol soil. At two initial inoculation concentrations about 103 and 106 conidia g-1 of soil the CFU amount in 1 g soil gradually were stabilized at a level about 105 g-1 of soil. The population density on this level was stable for 6 months. Inoculation of the creeping roots at different stages of their development (creeping roots with buds/rosettes/young roots) in laboratory conditions showed that fungus can infect leaves only in rosettes. It seems, under natural conditions, infection of Canada thistle root system with S. cirsii is not possible. However, S. cirsii maintains viability under various conditions of over-wintering (above/under/on ground).

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177-180 I. Gaurilčikienė and A. Ronis
The effect of strobilurin fungicides on the development of foliar diseases of winter wheat
Abstract |

The effect of strobilurin fungicides on the development of foliar diseases of winter wheat

I. Gaurilčikienė and A. Ronis

Lithuanian Institute of Agriculture, Instituto al. 1, LT–58344 Akademija, Kėdainiai distr.,Lithuania; e–mail: irenag@lzi.lt

Abstract:

The present paper reports the results of field research into the epidemic progress of fungal leaf diseases in winter wheat cv. Zentos. Experiments were conducted during the period 2003–2004 and were designed to study the impact of strobilurins krezoxim–methyl+ epoxyconazole+fenpropimorf, trifloxystrobin+propiconazole, azoxystrobin, piraclosrobin+ epoxyconazole and picoxystrobin on the epidemic progress of Stagonospora leaf blotch (Stagonospora nodorum (Berk.) Cast. and tan spot (Pyrenophora tritici-repentis (Died.) Drechs.) and to compare with triazoles epoxyconazole and propiconazole. In both years the pressure of fungal leaf diseases was severe. The unusually hot period during the wheat ripening stage in 2003 provoked the intense outbreak of tan spot. However, the warm and rainy prolonged ripening season in 2004 promoted the severe infection of Stagonospora blotch. Our experimental findings suggest that both strobilurin and triazole fungicides significantly suppressed the epidemic progress of Stagonospora leaf blotch and tan spot on the upper three leaves of winter wheat. The lowest AUDPC (Area Under the Disease Progress Curve) value in both years (2003 and 2004) was recorded in the treatment with piraclosrobin+epoxyconazole, while the highest, in the treatment applied with triazole propiconazole. AUDPC of the other strobilurin fungicides ant triazole epoxyconazole were comparable. AUDPC of both Stagonospora leaf blotch and tan spot on the upper leaves (F, F–1 and F–2) showed the strong negative linear correlation with the grain yield and 1000 grain weight (TGW).

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181-186 M. Grišakova, L. Metspalu, K. Jõgar, K. Hiiesaar, A. Kuusik and P. Põldma
Effects of biopesticide Neem EC on the Large White Butterfly, Pieris brassicae L. (Lepidoptera, Pieridae)
Abstract |

Effects of biopesticide Neem EC on the Large White Butterfly, Pieris brassicae L. (Lepidoptera, Pieridae)

M. Grišakova, L. Metspalu, K. Jõgar, K. Hiiesaar, A. Kuusik and P. Põldma

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,Kreutzwaldi St. 64, 51014 Tartu, Estonia; e-mail: luule.metspalu@emu.ee

Abstract:

The effects of Neem EC (M/S RYM Exports – The Indian Neem Tree Company, 1% azadirachtin) were assessed on the Large White Butterfly, Pieris brassicae – a major pest of cruciferous plants. Duration of the larval stage, mortality of larvae and prepupae, and weight of pupae were studied. The time needed for completion of the larval stages by individuals fed on treated cabbage increased significantly, compared with the control: 16–37 days in the test variant, versus 11–18 days in the control. Neem EC also induced high mortality, caused by lethal failures of larval-larval and larval-pupal ecdysis, which were typical for insecticides possessing morphogenetic activity commonly referred to as IGR-activity. The mortality of larvae and prepupae in the test variant was significantly higher than in the control. Considerably fewer pupae were gained in the test variant than in the control variant. The pupae of larvae that had been feeding on the control were significantly heavier than those of the larvae feeding on the treated plants. The experiment revealed that Neem EC had both toxic and antifeedant/deterrent effects but also acted as a growth regulator for P. brassicae larvae.

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187-190 L. Hanni and A. Luik
Parasitism of raspberry beetle (Byturus tomentosus F.) larvae in different cropping techniques of red raspberry
Abstract |

Parasitism of raspberry beetle (Byturus tomentosus F.) larvae in different cropping techniques of red raspberry

L. Hanni¹ and A. Luik²

¹Polli Horticultural Research Centre, Institute of Agricultural and Environmental Sciences,Estonian University of Life Sciences, Viljandi county, Karksi–Nuia, Polli, 69104, Estonia;e-mail: liina.hanni@emu.ee
²Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,Kreutzwaldi St. 64, 51014, Tartu, Estonia

Abstract:

Raspberry beetle (Byturus tomentosus F.) is the major pest in raspberry in Estonia and throughout Europe. The parasitism rate of raspberry beetle larvae was studied in different cropping systems and in wild raspberry. In the raspberry plantation two intercropping systems were used: intercropping with 7 herbs and with black currant. The control variant was monocropping. Larvae from wild raspberries were collected from a clear cut area in the neighbourhood of the plantation. In the monocropping area the larval parasitism rate was less than 5%. The intercropping of raspberries with herbs increased the larval parasitism rate (9.4%), while in the intercropping with black currant, it decreased (2.2%). Larvae from wild raspberry were the most parasitized (26.1%). Further investigation is needed to explain species composition of parasitoids in raspberry beetle larvae.

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191-196 K. Hiiesaar, L. Metspalu and K. Jõgar
Attractiveness and susceptibility of Brassica rapa, B. napus and Sinapis alba to the flea beetles (Coleoptera: Chrysomelidae)
Abstract |

Attractiveness and susceptibility of Brassica rapa, B. napus and Sinapis alba to the flea beetles (Coleoptera: Chrysomelidae)

K. Hiiesaar, L. Metspalu and K. Jõgar

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,Kreutzwaldi St. 64, EE51014 Tartu, Estonia; e-mail: kylli.hiiesaar@emu.ee

Abstract:

The attractiveness and susceptibility of three different cruciferous plant species – turnip rape, Brassica rapa, oilseed rape, B. napus var. oleifera subvar. annua and white mustard, Sinapis alba – to flea beetles of genus Phyllotreta (Coleoptera: Chrysomelidae) was studied. Despite the fact that the number of flea beetles on S. alba was almost the same as on the other plant species, damage to B. rapa and B. napus exceeded damage to S. alba throughout the observation period, P < 0.05. Flea beetles preferred to forage on B. napus:100% of the plants exhibited holes from eating both in cotyledon and in the first true leaf stage. Although 100% of plants of B. rapa were also damaged in seedling stage, in true leaf stage damage extended only to about 70%. Significantly less feeding damage occurred on S. alba, where eating traces were counted on about 70% of seedlings and less than 50% in true leaf stage. The mean damage score of S. alba was the lowest, 1,5 at the cotyledon stage and only feeding punctures, not shooting holes, were found on the leaves; the majority of the true leaves were undamaged or had single superficial holes. Most severely damaged was B. napus: the mean damage rating, 2.7 in the cotyledon stage and somewhat less, 2.4 in true leaf stage. B. .rapa had intermediate damage rating 2.2 in cotyledon stage and 1.9 in true leaf stage.

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197-201 D. Jodaugienė, R. Pupalienė, M. Urbonienė, V. Pranckietis and I. Pranckietienė
The impact of different types of organic mulches on weed emergence
Abstract |

The impact of different types of organic mulches on weed emergence

D. Jodaugienė, R. Pupalienė, M. Urbonienė, V. Pranckietis and I. Pranckietienė

Lithuanian University of Agriculture, Studentų 11, Akademija, Kauno rajonas 53076,Lithuania; e-mail: Darija.Jodaugiene@lzuu.lt

Abstract:

A two – factor experiment was carried out in the Experiment Station of Lithuanian University of Agriculture in 2004 – 2005. Different organic mulches, chopped wheat straw, peat, wood chips, grass and wood chips, and wood chips which had been stored for 8 years (only in 2005) were overspead by a layer of 5 cm and 10 cm thickness. The influence of different organic mulches on weed emergence was evaluated. All organic mulches reduced weed germination. The positive effect of mulches was particularly obvious in the period of intensive germination of weeds. Straw, peat and wood chips had the strongest influence on the decrease of weed germination, however, it is important to make sure that mulches are not infected with weed seeds. Mulch of chopped grass is quick to decompose, therefore, repeated mulching is required to protect the crop from weeds. Key wods: organic mulches, weed emergence, annual weeds, perennial weeds

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203-210 K. Jõgar, A. Kuusik, L. Metspalu, K. Hiiesaar, A. Luik and M. Grishakova
Results of treatments with natural insecticidal substances on the development and physiological state of insects
Abstract |
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Results of treatments with natural insecticidal substances on the development and physiological state of insects

K. Jõgar, A. Kuusik, L. Metspalu, K. Hiiesaar, A. Luik and M. Grishakova

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,64 Kreutzwaldi St., 51014 Tartu, Estonia; e-mail: katrin.jogar@emu.ee

Abstract:

Reviewed are the results of treatments carried out in the Institute of Agricultural and Environmental Sciences of treatments with natural insecticidal substances on the development and physiological state of insects, using neurotoxical plant extracts (pyrethrins), plant extracts possessing several modes of action (neem) and an Insect Growth Regulator (extract of Ledum palustre possessing properties of juvenile hormone). Physiological changes evoked with treatments were monitored by means of complex methods including a constant volume respirometer, infrared actograph, infrared gas analyzer (IRGA),and a microcalorimeter.Diapausing lepidopterous pupae (Pieris brassicae, Mamestra brassicae) exhibiteddiscontinuous gas exchange cycles (DGCs). After treatments of the pupae of P. brassicae with neem, the DGCs were abolished, suggesting direct action on the neuromuscular system. The disappearance of DGCs was accompanied with lethal desiccation, supporting the hypothesis that DGC is an adaptation for restricting the respiratory water losses. Cyclic gas exchange was also lost after treatments with neem in adults of Leptinotarsa decemlineata. The clear gas exchange cycles in the pupae of Galleria mellonella, Tenebrio molitor and P. brassicae were also abolished after treatments with extracts of Artemisia vulgaris, Tanacetum vulgare, T. roseum and L. palustre. The timing of the normal and failed ecdysis (after treatment with L. palustre) as well as length of intercdysial periods in T. molitor pupae was measured exactly from calorimetric recordings. The treated pharate pupae transformed into extra-pupal instars, which is a symptom of juvenilizing effect.

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211-216 R. Karise, M. Mänd, M. Ivask, E. Koskor and A. Bender
The effect of pollen amount and its caloric value in hybrid lucerne (Medicago x varia) on its attractiveness to bumble bees (Bombus terrestris)
Abstract |
Full text PDF (141 kB)

The effect of pollen amount and its caloric value in hybrid lucerne (Medicago x varia) on its attractiveness to bumble bees (Bombus terrestris)

R. Karise¹, M. Mänd¹, M. Ivask², E. Koskor¹ and A. Bender³

¹Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,Kreutzwaldi St. 64, Tartu 51014, Estonia; e-mail: reet.karise@emu.ee
²Institute of Sustainable technology at Tallinn University of Technology,Akadeemia 4, Tartu 51003
³Jõgeva Plant Breeding Institute, 48309 Jõgeva, Estonia

Abstract:

Bumble bees forage for pollen and nectar on various plant species, but individuals often restrict their choice to a few flower types. The aim of this work was to study whether there is variation in certain pollen characteristics between differently coloured flowers of hybrid lucerne and whether this could be the reason why bumble bees prefer one flower type to another. The pollen amount, pollen grain size and the caloric values from different flower types were analysed to study the reasons for flower colour preference. On two cultivars of hybrid lucerne (Medicago x varia Mart.) the yellow flowers were preferred, but the reasons for the preference differed.

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217-220 D. Kavaliauskaitė and Č. Bobinas
Determination of weed competition critical period in red beet
Abstract |

Determination of weed competition critical period in red beet

D. Kavaliauskaitė and Č. Bobinas

Lithuanian Institute of Horticulture, LT-54333 Babtai, Kauno 30, Kaunas distr.,e-mail: d.kavaliauskaite@lsdi.lt

Abstract:

The field experiment was conducted at the Lithuanian Institute of Horticulture from 2000-2002 to determine the critical period of weed competition in red beet (Beta vulgaris L.) hybrid ‘Pablo’ crop. Weeding was delayed until 2, 4, 6, 8, 10, 12 weeks after red beet germination (WAG) and was carried out during the first 2, 4, 6, 8, 10, 12 WAG. Weed competition during the first 10 to 12 WAG reduced the marketable yield of red beet by 100%. Competition in the first 8 WAG reduced yield by 92.2%. Competition in the first 2 WAG had no adverse effect on yield; there was only an 8.3% reduction of red beet yield. A period of weeding for 4 WAG provided a yield similar to that achieved with 6 weeks of weeding. It is concluded that the first 4 WAG are the most critical for weed competition in red beet crop at a 5% yield loss level. Weeds emerging later do not appear to be detrimental to red beet growth and marketable yield.

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221-225 P. Kerpauskas, A. P. Sirvydas,P. Lazauskas, R. Vasinauskiene and A. Tamosiunas
Possibilities of weed control by water steam
Abstract |
Full text PDF (265 kB)

Possibilities of weed control by water steam

P. Kerpauskas, A. P. Sirvydas,P. Lazauskas, R. Vasinauskiene and A. Tamosiunas

Lithuanian University of Agriculture, Department of Heat andBiotechnology engineering, Kauno r. Studentu 15, LT 53356, Lithuania;tel: (+370) 37 75 23 17; fax: (+370) 37 75 23 24; e-mail: paulius.kerpauskas@lzuu.lt

Abstract:

Damp water steam used for weed control in onion, barley and maize crops was investigated meaningfully for the first time in the world. These investigations show that damp water steam can be successfully used in organic and traditional agriculture for weed control. During weed control by steaming, up to 98% of weed shoots are destroyed. After two weed control treatments by damp water steam in an onion field, the crop yield increased up to 9−10%, compared with three times of weeding; in the maize crop 22%, in the barley crop 10%, compared with the not weeded control.

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227-230 R. Kevväi, E. Veromann, A. Luik and M. Saarniit
Cabbage seed weevil (Ceutorhynchus assimilis Payk.) and its parasitoids in oilseed rape crops in Estonia
Abstract |

Cabbage seed weevil (Ceutorhynchus assimilis Payk.) and its parasitoids in oilseed rape crops in Estonia

R. Kevväi, E. Veromann, A. Luik and M. Saarniit

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,Kreutzwaldi St. 64, EE51014, Tartu, Estonia; e-mail: reelika.kevvai@emu.ee

Abstract:

Abstract: Besides pollen beetles, the cabbage seed weevil is the second most numerous crucifer-specialist in Estonian oilseed rape crops. The occurrence of cabbage seed weevil and its hymenopterous parasitoids was studied in standard and integrated cropping systems in winter and spring oilseed rape crops in 2004–2005. Cabbage seed weevil is more synchronized with winter oilseed rape and its abundance was greater in winter than in spring. The average pod damage was 9.9% in winter and only 1.2% in the spring crop. In winter oilseed rape, the population of C. assimilis was more numerous in the integrated than in the standard cropping system. Three parasitoids of seed weevil – Trichomalus perfectus, Stenomalina gracilis, Mesopolobus morys – were caught with yellow water traps but their abundance was low. The larval parasitism rate was higher in the integrated cropping system (22.2%) than in the standard cropping system (9.7%). Trichomalus perfectus was the dominant species emerging from C. assimilis larvae.

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231-236 I. Kokina and I. Rashal
Monitoring the population of Blumeria graminis f. sp. hordei in the South-Eastern part of Latvia
Abstract |
Full text PDF (142 kB)

Monitoring the population of Blumeria graminis f. sp. hordei in the South-Eastern part of Latvia

I. Kokina¹ and I. Rashal²

¹Department of Biology, University of Daugavpils, Vienības Str. 13, LV-5401, Latvia;e-mail: inese.kokina@navigator.lv;
²Institute of Biology, University of Latvia, Miera Str. 3, Salaspils, LV-2169, Latvia;e-mail: izaks@email.lubi.edu.lv

Abstract:

The population of Blumeria graminis f.sp. hordei in the South-Eastern part of Latvia (Latgale region) has been monitored since 1995. In 2005, samples of the pathogen were collected both as conidia and cleistothecia from commercial barley fields. Frequencies of virulence genes, pathotypes and their complexity were calculated. Genes Va1, Va3 and Va13 were presented with medium-high frequencies and frequencies of Va6, Va7, Va9, Va12, Vk and VLa ranged from medium-high to high. A large number of pathotypes was detected, which reflects wide genetic diversity in the pathogen population.

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237-240 M. Kopacki and A. Wagner
Effect of some fungicides on mycelium growth of Fusarium avenaceum (Fr.) Sacc. pathogenic to chrysanthemum (Dendranthema grandiflora Tzvelev)
Abstract |

Effect of some fungicides on mycelium growth of Fusarium avenaceum (Fr.) Sacc. pathogenic to chrysanthemum (Dendranthema grandiflora Tzvelev)

M. Kopacki and A. Wagner

Department of Plant Protection and Quarantine, Agricultural University,Leszczynskiego 7, 20-069 Lublin, Poland; e-mail: marek.kopacki@ar.lublin.pl

Abstract:

Ten fungicides were tested in vitro for their effectiveness to inhibit the linear growth of three isolates of Fusarium avenaceum of proven pathogenicity to chrysanthemum. The measurements were taken after 4 and 8 days of fungus growth in the presence of fungicides in three concentrations. The most effective in vitro proved to be the fungicides containing difenaconazole, carbendazim and flusilazol while the least effective were mancozeb, chlorothalonil and captan. The isolates of F. avenaceum differed in their susceptibility to tested fungicides.

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241-245 J. Korolova, D. Lapinsh and A. Berzinsh
Weed dynamics in differently managed fields
Abstract |

Weed dynamics in differently managed fields

J. Korolova¹, D. Lapinsh² and A. Berzinsh²

¹Department of Control System, Latvia University of Agriculture, Liela iela 2, Jelgava, Latvia;e-mail: jelena.korolova@llu.lv
²Institute of Soil and Plant Sciences, Latvia University of Agriculture, Liela iela 2, Jelgava,Latvia; e-mail: dainis.lapins@llu.lv; andris.berzins@llu.lv

Abstract:

Latvia is characterized by variation among farms. Analysis of the dynamics of weed diversity is based on monitoring sowings during 1997–2004 in westerly and central regions of Latvia. The aim of this research was to compare the dynamics of weed on unchanging types of grain sown, fields with elevated grain density and un-utilised agricultural land. Two hypotheses were put forward: the dynamic of several species of weeds to impact the total number of weeds in land laying waste (un-utilised agricultural land), and the increase in the numbers of several specific weeds in fields with elevated grain density using annual herbicides.

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247-250 J. Lanauskas, N. Uselis, A. Valiuškaitė and P. Viškelis
Effect of foliar and soil applied fertilizers on strawberry healthiness, yield and berry quality
Abstract |
Full text PDF (128 kB)

Effect of foliar and soil applied fertilizers on strawberry healthiness, yield and berry quality

J. Lanauskas¹, N. Uselis², A. Valiuškaitė² and P. Viškelis²

¹Lithuanian Institute of Horticulture, Kauno 30, LT–54333 Babtai, Kaunas distr., Lithuania;e–mail: j.lanauskas@lsdi.lt
²Lithuanian Institute of Horticulture, Kauno 30, LT–54333 Babtai, Kaunas distr., Lithuania;e–mail: institutas@lsdi.lt

Abstract:

The effect of foliar applied fertilizers (calcium nitrate, Kemira Ferticare 7–27–25, Phosfik 3–27–18 and Biokal 01) and calcium nitrate broadcasted to the soil on strawberries cv. ’Honeoye’ was investigated in 2004–2005 at the Lithuanian Institute of Horticulture. Strawberries were sprayed three times starting at full bloom in 8 day intervals. Calcium nitrate was applied to the soil in the rows during full bloom at the rate of 150 kg ha-1. Control plants were not fertilized. Ecological preparation Biokal 01 decreased amount of mite–infested strawberry plants by 9 percent units, and the incidence of leaf scorch (Diplocarpon earlianum (Ellis & Everh) Wolf) by 8 percent units in comparison with the control. Fertilizers had no effect on white leaf spot (Mycosphaerella fragariae (Tul.) Lind) infection. Foliar applied fertilizers had no positive effect on strawberry yield, average berry weight and berry firmness. Calcium nitrate applied to the soil decreased berry firmness. Biokal 01 and foliar applied calcium nitrate increased berry sucrose content. Fertilizers did not influence concentration of soluble solids, total sugars, ascorbic acid, nitrates and titratable acids.

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251-255 A. Leistrumaitė and Ž. Liatukas
Resistance of spring barley cultivars to the new disease Ramularia leaf spot, caused by Ramularia collo-cygni
Abstract |
Full text PDF (127 kB)

Resistance of spring barley cultivars to the new disease Ramularia leaf spot, caused by Ramularia collo-cygni

A. Leistrumaitė and Ž. Liatukas

Lithuanian Institute of Agriculture, Instituto al. 1, Akademija,Kėdainiai distr., LT-58344, Lithuania; e-mail: alge@lzi.lt

Abstract:

In 2004 and 2005, the occurrence of Ramularia leaf spot was monitored at breeding nurseries of spring barley. Higher Ramularia severity developed in the dryer and sunnier year of 2005. Generally, resistance of cultivars to Ramularia leaf spot was similar between years. Half of the tested cultivars were more damaged by Ramularia in the second year. Average disease severity increased from 7.0% in 2004 to 13.4% in 2005. The correlation analysis showed no relationship between Ramularia and other diseases severities. The effect of Ramularia AUDPC on the yield in 2005 showed weak negative correlation (r = -0.37*). It can be explained by higher Ramularia and lower severities of other diseases. Among the tested cultivars there were identified genotypes with a high complex resistance to all foliar diseases. Such cultivars were Jersey, Philadelphia and Wikingett.

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257-261 Ž. Liatukas and V. Ruzgas
Peculiarities of selection for winter wheat resistance to common bunt
Abstract |

Peculiarities of selection for winter wheat resistance to common bunt

Ž. Liatukas and V. Ruzgas

Lithuanian Institute of Agriculture, Instituto al. 1, Akademija, Kedainiai distr., LT-58344,Lithuania; e-mail: liatukas@lzi.lt

Abstract:

The effects of the years on the level of infection, and the impact of the number of replications on the reliability of cultivar resistance were studied in an artificially inoculated nursery over a period of twelve years from 1993–2004. The aim of the tests was to ascertain how many years of testing and how many replications are necessary to reveal the actual bunt resistance of a variety. During the study period we tested over 2000 cultivars differing in origin, and advanced breeding lines. Some were investigated for up to 8 years. Average disease incidence varied from 6.3 to 47.9%, depending on the experimental year. Bunt incidence was considerably variable between replications and especially over years. This suggests that the effectiveness of short-term testing of common bunt is very low. To achieve precise assessment of wheat resistance to common bunt, the following experimental design should be pursued: at least three plot replications, the use of several standard cultivars with known resistance level, and at least three repetitions in the years with diverse disease severity.

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263-267 I. Liblikas and S. Kuusik
Pheromone research in Estonia
Abstract |

Pheromone research in Estonia

I. Liblikas and S. Kuusik

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,Kreutzwaldi St. 64, 51014 Tartu, Estonia; e-mail: ilmel@kth.se, ilme.liblikas@eau.ee

Abstract:

The pheromone screening of nineteen insect species was conducted in different habitats and geographical regions of Estonia. The purpose of this screening was to measure the population density of selected insects to sort out species suitable for environmental monitoring. The other research objective was to standardize the pheromone materials for plant protection as alternative approaches to the use of conventional pesticides. To monitor the changes in environment Archips podana, Hedya nubiferana, Choristoneura diversana, Enarmonia formosana, Tortrix viridana, Archips xylosteana and Cerapteryx graminis showed great potential. In fruit gardens the pheromone kit for codling moth Cydia pomonella is recommended. The pheromone dispenser for Currant shoot borer, Lampronia capitella, is the first of its kind. in the world.The old-fashioned Russian-made substrate was successfully replaced by Hevea’s rubber-and silicone-based materials. Our laboratory is ready for lab-scale production of all tested dispensers.

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269-272 A. Lind, A.-J. Martin, Ü. Aron, K. Hiiesaar, E. Koskor and T. Lukas
Development and control of mound nests of black garden ant (Lasius niger) in farmland
Abstract |

Development and control of mound nests of black garden ant (Lasius niger) in farmland

A. Lind, A.-J. Martin, Ü. Aron, K. Hiiesaar, E. Koskor and T. Lukas

Institute of Agricultural and Environmental Sciences,Estonian University of Life Sciences,64 Kreutzwaldi St., 51014 Tartu, Estonia; e-mail: ave.lind@mail.ee

Abstract:

The aim of this study was to investigate development of mound nests of Lasius niger treated with ant repellents compared with untreated habitats in agricultural landscapes. The research was carried out in Kiidjärve, Põlva County, in 2004. After transferring a group of ant colonies to new locations, some small new nests had been slowly rebuilt on nest bases which had not been treated with repellents. The nest bases treated with repellents were abandoned, and new mounds were not restored in those locations. After treating the interior of undamaged nests with injections of tobacco dust and a water solution of Fairy (a liquid soap used for dishwashing), tobacco dust, and Cayenne pepper, the colonies started to weaken and the mound increase was negative. The height and diameter of the untreated control nests increased. Test results indicate that the best way to eliminate Lasius niger and other soil-living ants is to transplant the nests to new sites, then treat transplanted nest bases with repellents. It is necessary to transplant the subterranean part of the nest with hibernation chambers, including removal of the queens and worker ants taking care of them. The treatment of nest interiors with repellents (tobacco dust, Cayenne pepper) caused weakening of the colony, elimination of the brood growth and decrease of the building activity.

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273-280 H. Lõiveke
Incidence of Fusarium spp. on several field crops in Estonia and their toxicity towards Bacillus stearothermophilus
Abstract |
Full text PDF (115 kB)

Incidence of Fusarium spp. on several field crops in Estonia and their toxicity towards Bacillus stearothermophilus

H. Lõiveke

Estonian Research Institute of Agriculture, Teaduse 13, EE75501 Saku, Harjumaa, Estonia;e-mail: heino.loiveke@eria.ee

Abstract:

The article provides an overview of the occurrence of Fusarium spp. on grain produced in Estonia from 1973–2004, the occurrence of Fusarium spp. in the common root rot complex of cereals in 1977–1985 and potato tubers with dry rot symptoms in the yield of 1996–2000. The dominating species on grain were (contaminated samples, %) F. avenaceum (Fr.) Sacc. – 28.0–30.3; F. poae (Pk.) Wr. – 7.4–9.5 F. semitectum Berk. et Rav. – 7.0–9.0; F. oxysporum (Schlecht) Snyd. et Hans. – 7.4-8.0; accompanied by F. ventricosum App. et Wr., F. sporotrichioides Sherb. var. minus Wr., F. verticillioides (Sacc.) Nirenberg, F. culmorum (W. G. Sm.) Sacc. and F. sambucinum Fuck. In the common root rot complex of barley, F. culmorum – 16.8; F. sambucinum – 2.5; F. avenaceum – 2.2; F. oxysporum – 1.7; and F. poae – 1.3 (contaminated samples, %) dominated. In potato with dry rot, F. culmorum – 26.7; F. solani (Mart.) Sacc. – 20.0; F. poae – 15.0; F. oxysporum – 13.3 and F. sulphureum Schlecht – 8.3 (contaminated tubers, %) dominated. The occurrence of toxic isolates both on grain and potato was established. Of Fusarium isolates recovered from grain (total 287) 5.6% were highly toxic, and 88.1% mildly or medium toxic to Bacillus stearothermophilus. Of 15 isolates found on potato, 1 was highly toxic and 9 were mildly to medium toxic. Fusarium spp. has been presented according to Gerlach & Nirenberg (1982).

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281-285 S. Maiksteniene and A. Arlauskiene
The effect of agricultural management systems on the weed incidence in cereals
Abstract |

The effect of agricultural management systems on the weed incidence in cereals

S. Maiksteniene and A. Arlauskiene

Joniskelis Research Station of the Lithuanian Institute of Agriculture, Joniskelis,LT-39301 Pasvalys District, Lithuania; e-mail: joniskelio_lzi@post.omnitel.net

Abstract:

Two field trials were carried out at the Lithuanian Institute of Agriculture’s Joniskelis Research Station on an Endocalcari-Endohypogleyic Cambisol. The experiments were designed to identify the effects of legume pre-crops and intercrops as well as the impact of their biomass incorporated as green manure on the weed incidence in succeeding cereals. The effects of legume pre-crops red clover, sown lucerne, and vetch and oats mixture on the incidence of weeds were determined by their weed incidence and the cereal crop’s suppressive power that formed under its effect. Undersown intercrops (Trifolium pratense L., Lolium multiflorum Lam., Dactylis glomerata L.), reduced the number of weeds in cereals (on average 13.9%). During the cereal post-harvest period red clover performed best at suppressing weeds, and its positive effect persisted in the year following incorporation of intercrops biomass. The effect of intercrops as post-crops (Raphanus sativus L., Sinapis alba L.) on weed incidence in the cereal crop depended upon the weather conditions that determined intercrop emergence time and intensity of plant development.

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287-292 S. Maļecka and G. Bremanis
Effectivity of reduced dosages of herbicides to weed constitution of spring barley I
Abstract |
Full text PDF (100 kB)

Effectivity of reduced dosages of herbicides to weed constitution of spring barley I

S. Maļecka and G. Bremanis

State Stende Plant Breeding Station, Dizstende, LV 3258, Talsi district, Latvia;e–mail: stende.selekcija@apollo.lv

Abstract:

The barley variety ‘Ansis’ was cultivated in the field at the State Stende Plant Breeding station, 2001–2004, in sod podzolic and sod–gleysolic sand loamy soil with neutral soil response. Average annual dicotyledonous weed infestation level in trial years differed: 106.9 weed plants per m2 in the year 2001; 213 in 2002; 22.7 in 2003, and 216 in 2004. Thlaspi arvense (L.) was the most widespread weed in 2001, 2002 and 2004 trial years, but Chenopodium spp. was dominant in 2003–2004, and Polygonum convolvulus (L) in 2004. Lamium spp. was also widespread in all-trial years, Viola arvensis (Murray) in 2001, 2002 and 2004; Stellaria media (L.) in 2002 and 2003, and Capsella bursa–pastoris (L.) in 2002 and 2004.The effect of herbicides is usually calculated as decrease in weed number and as decreaseof fresh weight of weeds (% to control or % to initial amount). In this article the ratio of one weed’s weight after herbicide use to one weed’s weight in control is recommended for comparing effectiveness of the doses of herbicides to weeds. The effectiveness of herbicides is estimated as a special factor EfKo. The reduction of herbicide doses to one half or one fourth of recommended dosage usually had no significant effects on weed control.

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293-297 A. Marcinkevičienė, S. Raudonius and R. Velička
Weed suppression by increasing spring rape crop density
Abstract |
Full text PDF (134 kB)

Weed suppression by increasing spring rape crop density

A. Marcinkevičienė, S. Raudonius and R. Velička

Lithuanian University of Agriculture, Studentu 11, Akademija, Kaunas district, LT-53067,Lithuania, e-mail: lzuustotis@hotmail.com, steponas.raudonius@lzuu.lt

Abstract:

Field experiments were conducted in 2003 and 2004 at the Experimental Station of the Lithuanian University of Agriculture to study the influence of different spring rape (Brassica napus L.) densities (50.1–100, 100.1–150, 150.1–200, 200.1–250, 250.1–300, 300.1–350, 350.1–400, 400.1–450 plants m-2) on weed abundance. Increase of crop density and herewith increase of canopy should intensify the competition ability of spring rape plants and suppress weeds better. The results show that light intensity on the soil surface decreases when the assimilation area of spring rape leaves and total crop biomass increases. Weed density decreases when spring rape crop is densier. A significant negative relationship exists between weed biomass and spring rape leaf area index (LAI) (r = -0.62, P < 0.05), as well as between weed biomass and spring rape biomass (r = -0.67, P < 0.01). A significant positive correlation appears between weed abundance and light intensity on soil surface (r = 0.68, P < 0.01).

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299-302 E. Merivee, A. Must, M. Milius and A. Luik
External stimuli in searching for favourable habitat, overwintering sites and refugia of ground beetles: a short review
Abstract |

External stimuli in searching for favourable habitat, overwintering sites and refugia of ground beetles: a short review

E. Merivee, A. Must, M. Milius and A. Luik

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,Kreutzwaldi St. 64, 51014 Tartu, Estonia; e-mail: enno.merivee@emu.ee

Abstract:

More than 10 morphological types and subtypes of sensilla have been found on the antennae of ground beetles. On the basis of their external features and similarity with the antennal sensilla of other insects, it is suggested that they may function as mechano-, olfactory, taste, thermo- and hygroreceptors. In ground beetles, however, a thermoreceptive cell located in antennal campaniform sensilla, and three chemoreceptive cells of four, innervating large antennal taste bristles have been electrophysiologically identified. These cells are the salt, pH and sugar cell. Their probable role in searching for favourable habitats, overwintering sites and refugia is discussed. It is concluded that the strength of external chemosensory stimuli to which antennal taste cells do not fire, or fire at very low frequency, represents chemical conditions in the ground beetles’ preferred habitats and microhabitats. In the future, a good knowledge of external stimuli crucial in the searching behaviour of ground beetles’ could allow more effective manipulation of these predatory beetles in agricultural lands..

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303-306 R. Mikaliūnaitė and Z. Dabkevičius
Efficacy of seed treaters on the germination of ergot (Claviceps purpurea (Fr.) Tul.) sclerotia and stroma formation
Abstract |
Full text PDF (126 kB)

Efficacy of seed treaters on the germination of ergot (Claviceps purpurea (Fr.) Tul.) sclerotia and stroma formation

R. Mikaliūnaitė and Z. Dabkevičius

Šiauliai University, Višinskio 19, Šiauliai, 77156, Lithuania; e-mail: OIKOS@fm.su.lt

Abstract:

The effects of the fungicidal seed treaters Baitan-Universal 19,5 WS and Divident Star 036 FS, Divident Star with bioactivator Penergetic-p and Penac as well as biopesticide Bionature R2000 applied alone on the germination of ergot (Claviceps purpurea (Fr.) Tul.) sclerotia and stroma formation were studied in the laboratory and field conditions in 2004 and 2005. Rye (Secale cereale L.) seed, contaminated with ergot sclerotia, was used for the tests. The rates recommended for rye seed treatment were applied.In the experiments 45.5–79.0% of untreated sclerotia germinated, and each sclerotiumformed on average 3.7–7.5 stromas. The fungicidal seed treaters tested inhibited and delayed sclerotia germination. In the laboratory conditions Baitan-Universal and Divident Star gave 86.1-100% suppression of sclerotia germination and 90.1–100% of stroma formation. Under the field conditions this suppression was lower: 46.2–68.8 % and 57.4–84.3%, respectively. Bioactivators did not exert any effect on sclerotia germination and stroma formation in the laboratory conditions, but they increased sclerotia germination by 3.3–15.3% and stroma formation by 19.5–96.0 units per 100 sclerotia in the field conditions. The biopesticide Bionature significantly inhibited stroma formation only in 2005.

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307-310 L. Narits
Occurrence of pests and stem rot on various oil crops
Abstract |

Occurrence of pests and stem rot on various oil crops

L. Narits

Jõgeva Plant Breeding Institute, Aamisepa 1, Jõgeva, 48309, Estonia;e-mail: Lea.Narits@jpbi.ee

Abstract:

The purpose of this study was to find an oil crop with no serious problems with pests and diseases, making it suitable for organic farms.The spring oilseed rape is the most important oil crop in Estonia. Winter turnip rape andwinter oilseed rape are alternatives to spring rape.In the present exploration the following were investigated: incidence of flea beetles,pollen beetles and cabbage seed weevils, and the number of blind stalks and infection of stem rot on spring oilseed rape, winter oilseed rape and winter turnip rape.In winter oilseed rape and winter turnip rape trials no pesticides and fungicides were usedduring the growing period, but there was a variant of seed treatment by ‘Rapcol’ (phurathiocarb + matalaxil + fludioxonil) in comparison with the non-treated variant. Spring oilseed rape trials were treated by ‘Rapcol’ before sowing and sprayed by ‘Fastac’ (alpha-cypermethrin) at the beginning of flowering (stage of development – 61).The following results were obtained: flea beetles appeared most on winter oilseed rape,least on winter turnip rape. Pollen beetles appeared most on spring oilseed rape, least on winter turnip rape. Most pods damaged by pollen beetles’ larvae were found on winter oilseed rape, least on winter turnip rape. Damage by cabbage seed weevil was minimal in all the oil crop trials. Stem rot infection was high on spring oilseed rape, least on winter turnip rape.By the results of exploration it can be concluded that winter turnip rape had the lowestinfection by pests and disease and therefore has good potential for sustainable agriculture.

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311-316 V. Pilipavicius, R. Romaneckiene, A. Ramaskeviciene and A. Sliesaravicius
The effect of CO2 and temperature combinations on Chenopodium album L. early growth
Abstract |

The effect of CO2 and temperature combinations on Chenopodium album L. early growth

V. Pilipavicius¹, R. Romaneckiene¹, A. Ramaskeviciene² and A. Sliesaravicius²

¹Lithuanian University of Agriculture, Dept. of Soil Management, Studentu 11, LT-53067Akademija, Kaunas r., Lithuania; tel.: +370 37 75 22 66; fax: +370 37 75 22 93;e-mail: vytautas.pilipavicius@lzuu.lt, romanr@one.lt
²Lithuanian University of Agriculture, Dept. of Plant Science and Animal Husbandry, Studentu11, LT-53067 Akademija, Kaunas r., Lithuania; tel.: +370 37 75 23 14;fax: +370 37 75 22 93; e-mail: astara@info.lzuu.lt, algir@nora.lzua.lt

Abstract:

Vegetative pots experiments were carried out at the Phytotron of the Lithuanian Institute of Horticulture in the period between January and September 2005. Four levels of CO2 concentration: 350 ppm (control treatment), 700 ppm, 1500 ppm, 3000 ppm and two levels of temperature regimes: 21oC/17oC (control treatment) and 25°C/21°C, photoperiod of 16/8 h, and their combinations were used in testing Chenopodium album L. early growth. The level of radiation (PAR) was 170 micro-mol m-2 s-1.Experimental data proved that the concentration of CO2, which had been graduallyincreasing and reached 1500 ppm, added to the length of Chenopodium album L. sprouts and increased the biomass of sprouts and roots. Chenopodium album L. was not able to adapt to further increase of CO2 concentration and had a tendency to retard the early growth. Increase of the environment temperature to 25°C/21°C initiated more intensive early growth of Chenopodium album L. increasing sprout length and quantity of the accumulated biomass. However, under the conditions of 25oC/21oC, the 700 ppm concentration of CO2 already had a negative impact on the early growth of Chenopodium album L.

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317-322 L. Raudonis
Comparative toxicity of spirodiclofen and lambdacihalotrin to Tetranychus urticae, Tarsonemus pallidus and predatory mite Amblyseius andersoni in a strawberry site under field conditions
Abstract |
Full text PDF (103 kB)

Comparative toxicity of spirodiclofen and lambdacihalotrin to Tetranychus urticae, Tarsonemus pallidus and predatory mite Amblyseius andersoni in a strawberry site under field conditions

L. Raudonis

Laboratory of Plant Protection, Lithuanian Institute of Horticulture,LT-54333 Babtai, Kaunas distr., Lithuania;e-mail: l.raudonis@lsdi.lt

Abstract:

The relative toxicity of broad-spectrum acaricide spirodiclofen 240 g AI l-1 from a new class of active ingredients and synthetic pyrethroid insecticide–acaricide lambdacihalotrin 50 g AI l-1 to the seasonal abundance of Tetranychus urticae Koch (Acari: Tetranychidae), Tarsonemus pallidus Banks (Acari: Tarsonemidae) and predatory mite Amblyseius andersoni Chant (Acari: Phytoseiidae) was evaluated in strawberry sites under field conditions in 2003–2004. The field rate (96 g AI ha-1) of spirodiclofen was very toxic (82.3–96.1% mortality) after 7 and 21 days after treatment to T. urticae. The mortality to T. pallidus ranged from 76.6- 79.3% after 7 days, and from 59.0–74.9% after 21 days following treatment respectively. The rate (48 g AI ha-1) of spirodiclofen was very toxic (78.8–87.8% mortality) after 7 days and moderately toxic (54.1–73.4% mortality) after 21 days following treatment to T. urticae. The lower rate of spirodiclofen was moderately toxic after 7 days and from non- to slightly toxic after 21 days following treatment to T. pallidus. The toxicity of lambdacihalotrin (25 g AI ha-1) to T. urticae was similar to a lower rate of Spirodiclofen. Lambdacihalotrin was non-toxic to T. pallidus, but moderately toxic (51.4–62.5% mortality) after 7 and 21 days following treatment to A. andersoni. Both rates of spirodiclofen were non-toxic to predatory mites.

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323-326 R. Reiman and L. Vakra
Environmental risk assessment of plant protection products
Abstract |

Environmental risk assessment of plant protection products

R. Reiman and L. Vakra

Estonian Plant Production Inspectorate, Teaduse 2, Saku, 75501, Estonia

Abstract:

Plant protection products (PPP’s) are hazardous chemicals that are intentionally spread into the environment. In order to protect human and animal health and the environment the risk assessment has to be performed before the authorisation of PPP’s. Risk assessment is based on the general principles and requirements laid down in the European Council Directive 91/414/EEC (concerning the placing of plant protection products on the market), international guidelines and Estonian legislation. This paper describes ecotoxicological and environmental risk assessment, the use of mathematical models and feasible risk mitigation measures to assure acceptable risk of PPP’s under the proposed conditions of use in Estonia.

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327-330 R. Repšienė and R. Nekrošiene
Resistance of red clover to diseases and pests under different growing conditions
Abstract |

Resistance of red clover to diseases and pests under different growing conditions

R. Repšienė¹ and R. Nekrošiene²

¹Vezaiciai Branch, Lithuanian Institute of Agriculture, Gargzdu 29, VezaiciaiLT-96216 Klaipeda distict, Lithuania; e-mail: regina@vezaiciai.lzi.lt
²Botanical Garden of Klaipeda University, Kretingos 92, LT-92327 Klaipeda, Lithuania;e-mail: bot.sodas@one.lt

Abstract:

Experiments were carried out in the Vėžaičiai Branch of the Lithuanian Institute of Agriculture (West Lithuania region) in 1998−1999 and 2005. The aim of this research was to estimate the incidence of diseases and pests of red clover in soils with different agrochemical characteristics. The soil acidity varied from 3.9-6.7, available P2O5 from 47–317, available K2Ofrom 100–360 mg kg-1, amount of humus from 1.71–2.36%. Ecological conditions of soils contained differing amounts of lime, mineral and organic fertilizers.Common leaf spot (agent Pseudopeziza trifolii (Biv.-Bern:Fr.) Fuskel) had a 1.3−1.7greater incidence on the red clover growing in the soil with pHKCl 3.9−4.9 in comparison withthose grown in the soil with pHKCl 5.7−6.7, and with intensively damaged red clover whichgrew in soils with fewer nutrients. Increasing the quantity of nutritious materials increased the incidence of powdery mildew (agent Erysiphe polygoni DC.) in 1999 and 2005 but reduced the incidence of clover seed weevil in soils with pHKCl 5.7−6.7 in those years.

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331-334 A. Ronis and R. Semaškienė
Development of tan spot (Pyrenophora tritici-repentis) in winter wheat under field conditions
Abstract |

Development of tan spot (Pyrenophora tritici-repentis) in winter wheat under field conditions

A. Ronis and R. Semaškienė

Department of Plant Pathology and Protection, Lithuanian Institute of Agriculture,Instituto aleja 1, Akademija, Kedainiai distr., LT 58344; e-mail: antanasr@lzi.lt

Abstract:

The pathogen that causes tan spot on wheat is Pyrenophora tritici-repentis (Died.) Drechs. (anamorph Drechslera tritici-repentis (Died.) Shoemaker). In recent years tan spot has become a potentially destructive disease of wheat in Lithuania and neighbouring countries. Three winter wheat cultivars (Aron, Tauras and Hereward) were grown during three seasons. Weather conditions were observed from April to August when the tan spot pathogen spreads. During the experimental years the weather conditions varied from season to season. A severe epidemic of tan spot occurred in 2004 when there was a sufficient amount of rain and the air temperature was close to optimal. The other two seasons were not extremely favourable for tan spot occurrence, especially in 2005, because of the lack of rain during the main growing period.Investigations of tan spot development patterns under field conditions enable wheatgrowers to better forecast tan spot and achieve better timing of fungicide applications.

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335-339 R. Rugienius, T. Siksnianas, V. Stanys, D. Gelvonauskiene and V. Bendokas
Use of RAPD and SCAR markers for identification of strawberry genotypes carrying red stele (Phytophtora fragariae) resistance gene Rpf1
Abstract |

Use of RAPD and SCAR markers for identification of strawberry genotypes carrying red stele (Phytophtora fragariae) resistance gene Rpf1

R. Rugienius*, T. Siksnianas, V. Stanys, D. Gelvonauskiene and V. Bendokas

Lithuanian Institute of Horticulture, Babtai LT-54333, Kaunas distr. Lithuania
*Corresponding author; e-mail: r.rugienius@lsdi.lt

Abstract:

Phytopthora fragariae is responsible for strawberry red stele disease that spreads in almost all areas where strawberries are grown. RAPD markers that were developed previously for the strawberry Rpf1 gene are difficult to reproduce and preferentially, therefore, should be converted into sequence characterized amplified region (SCAR) markers. The aim of our study was to develop new SCAR markers, associated with Rpf1, to make a comparative study of RAPD and SCAR markers, and to select strawberry varieties and seedlings carrying the Rpf1 gene. A SCAR marker was constructed based upon RAPD marker OPO-16C, linked to the susceptibility allele of the Rpf1 gene. Following the cloning and sequencing of this marker we were able to design SCAR primers specific to this gene. Utilizing newly developed SCAR markers it was shown that resistant varieties like ‘Anapolis’, ‘Redgauntlet’ contain Rpf1 region. Common varieties ‘Elsanta’, ‘Kama’, ‘Venta’, ‘Senga Sengana’ did not exhibit this gene. The segregation rate of seedling populations (susceptible x resistant) by this marker was approximately 1: 1.

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341-344 E. Runno and M. Koppel
The question of metalaxyl resistance on late blight fungus in Estonia
Abstract |

The question of metalaxyl resistance on late blight fungus in Estonia

E. Runno and M. Koppel

Jõgeva Plant Breeding Institute, Aamisepa St. 1, 48309 Jõgeva alevik, Estonia(Phone:+3727762790; Fax: +3727766902; E-mail: Eve.Runno@jpbi.ee)

Abstract:

Metalaxyl containing fungicides are commonly used by Estonian potato growers because of their efficiency in control of potato late blight. Metalaxyl-resistant isolates have become an important part of the Estonian population of Phytophtora infestans. The aim of the current study was to measure the frequency of metalaxyl resistance among the Estonian population of Phytophtora infestans and to test the efficacy of metalaxyl-based fungicides in controlling potato late blight. 138 isolates of Phytophtora infestans were collected from conventional, experimental and small scale growers’ fields in different parts of Estonia in 2003-2005 and were assessed for resistance to metalaxyl. Metalaxyl-resistant, intermediate and sensitive isolates were recorded at frequencies of 37.1, 45.4 and 15.1%, respectively. There were differences in frequency of metalaxyl resistance between different locations, years and different types of potato cultivations. Metalaxyl-resistant isolates were predominant (66.7%) on conventional potato fields in 2004 and 2005. Metalaxyl- resistant strains were not detected among isolates collected from the field where fungicide containing metalaxyl was not used. The increased frequency of metalaxyl-resistant isolates was detected in 2003-2005. Trials of late blight control with fungicides containing metalaxyl were performed in the same period. Metalaxyl showed lowered efficacy only in conditions of extreme late blight pressure in 2004. Therefore metalaxyl could be effectively used for control of potato late blight a maximum of two times during the growing period.

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349-352 A. Sasnauskas, D. Gelvonauskienė, B. Gelvonauskis,V. Bendokas and D. Baniulis
Resistance to fungal diseases of apple cultivars and hybrids in Lithuania
Abstract |
Full text PDF (124 kB)

Resistance to fungal diseases of apple cultivars and hybrids in Lithuania

A. Sasnauskas*, D. Gelvonauskienė, B. Gelvonauskis,V. Bendokas and D. Baniulis

Lithuanian Institute of Horticulture, LT-54334, Babtai, Kaunas district, Lithuania
* Corresponding author; e-mail: A.Sasnauskas@lsdi.lt

Abstract:

Thirty apple (Malus domestica Mill.) cultivars and hybrids were evaluated for resistance to scab (Venturia inaequalis (Cke.) Wint.), apple blotch (Phyllosticta mali Pr.at Del.) and canker (Nectria galligena Bres.). Resistance to scab and apple blotch were studied in 2003–2005 and to canker in 2005. Injuries caused by fungal diseases were evaluated according to a 6 point scale: 0 – no disease symptoms detected on leaves or branches, 5 – injured more than 75% of leaf area or, in the case of canker, the branch is girdled by distorted area. Meteorological conditions were favourable or moderately favourable for the development of pathogens. It was ascertained that apple hybrids No 20429 and No 20016 are characterized as complex-resistant to scab, apple blotch and canker. Cultivar ‘Kurnakovskoe’ and hybrids No 19399, No 19707, No 19646, No 19942, No 20235, No 20239, No 20978 and No 24-40-52 are characterized as complex-resistant to scab and apple blotch. Cultivars ‘Delikates’, ‘Anteĭ’, hybrids No 25-50-126 and No 25-50-132 were the most sensitive to scab; ‘Pamyať Syubarovoĭ’ and No 25-51-122, to apple blotch, and ‘Katja’, ‘Yubilyar’, ‘Pamyať Syubarovoĭ’, ‘Bolotovskoe’ and No 19942, to canker.

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353-357 V. Seibutis and I. Deveikyte
The influence of short crop rotations on weed community composition
Abstract |

The influence of short crop rotations on weed community composition

V. Seibutis and I. Deveikyte

Lithuanian Institute of Agriculture, Instituto aleja 1, Akademija, Kedainiai distr., LT-58344,Lithuania; e-mail: vytautas@lzi.lt, irenad@lzi.lt

Abstract:

Field experiments were designed to evaluate the effect of crop rotations on weed density and species composition. An 8-year study was initiated in Dotnuva (Lithuania) in 1997 on an Endocalcari-Endohypogleyic Cambisol. Ten crop rotations: peas–winter wheat–sugar beet–spring barley, peas–winter wheat–spring barley, peas–winter wheat-winter wheat, sugar beet-spring barley-winter wheat, sugar beet-peas-winter wheat, sugar beet-spring barley-peas, sugar beet-spring barley-spring rape, peas-winter wheat, sprig barley-sugar beet, winter rape-winter wheat and spring barley monocrops were investigated. It was revealed that weed densities varied between rotations. In winter wheat crops in all crop rotations the density of Fallopia convolvulus was high but there was less Lamium purpureum, Myosotis arvensis and Stellaria media at the end than at the beginning of crop rotations. The density of Elytrigia repens was high in most crop rotations investigated. The exception was crop rotations where sugar beet was involved, compared to a four-course rotation. The largest total of annual and perennial weeds was recorded in winter wheat, when the crop was grown after peas and winter rape. In all crop rotations, in the stands of spring barley the amount of Lamium purpureum, Tripleurospermum perforatum and Taraxacum officinale was 13–18% lower compared with the spring barley monocrop. Annual broad-leafed weeds in the spring barley monocrop were more numerous than in a four-course rotation but less numerous than in the other crop rotations.

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359-362 I. Sell
Size and shape of basidiospores in the Phellinus igniarius group
Abstract |

Size and shape of basidiospores in the Phellinus igniarius group

I. Sell

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,Riia St. 181, 51014 Tartu, Estonia; e-mail: Indrek.Sell@emu.ee

Abstract:

Phellinus igniarius group, one of the most important wood-rotting fungi of many deciduous trees, was described as two species (P. igniarius, P. nigricans) more than a hundred years ago. Nowadays, in this group there are known 11 macromorphologically similar species, nine out of which occur in Estonia (P. alni, P. cinereus, P. igniarius s. str., P. laevigatus, P. lundellii, P. nigricans, P. populicola, P. tremulae, P. tuberculosus). These species, difficult to distinguish morphologically, are genetically different.The aim of the study is to find possible differences in the size and shape of basidiosporesof the species of the Phellinus igniarius group. There are some clear differences in the spore size of the species, but even being statistically significant, they do not enable us to identify the specimens in all cases.

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363-366 R. Semaškienė, A. Mankevičienė, Z. Dabkevičius and S. Supronienė
Effect of fungicides on Fusarium infection and production of deoxynivalenol in spring cereals
Abstract |

Effect of fungicides on Fusarium infection and production of deoxynivalenol in spring cereals

R. Semaškienė, A. Mankevičienė, Z. Dabkevičius and S. Supronienė

Department of Plant Pathology and Protection, Lithuanian Institute of Agriculture,Instituto 1, LT 58344 Akademija, Kedainiu distr., Lithuania; e-mail: roma@lzi.lt, audre@lzi.lt

Abstract:

Field trials in spring wheat and spring barley were carried out over two years in Dotnuva, in the center of Lithuania. Different fungicidal spray programs were used in 2004-2005 to determine their efficacy in controlling Fusarium infection and toxin deoxynivalenol (DON) accumulation in the grain. Azoxystrobin alone, and in a tank mixture with tebucanozole, a commercial mixture of prothioconazole and tebuconazole were used in spring barley. Epoxiconazole commercial mixture with pyraclostrobin and fenpropimorph, and tebuconazole alone were used in spring wheat. Fungicides were used at booting and heading or flowering stages. Naturally contaminated freshly harvested grain was analyzed. The Fusarium fungi infection level in grain was very high in both experimental years: in 2004 the level was 38.5–50.0%, and in 2005,45.0–70.8%. A lower percent of infected grains was found in spring wheat compared with spring barley. During 2004 there was identified 16.8–28.3% infection level; in 2005, 28.3–49.3%. Only in 2005 did fungicide treatments at heading or flowering slightly reduce the Fusarium infection. The level of mycotoxin DON detected in the grain samples was generally low and varied from 21 to 168 µg kg-1.

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367-370 T. Siksnianas, V. Stanys, G. Stanienė, C. Bobinas,A. Sasnauskas and R. Rugienius
Resistance to fungal diseases of interspecific currant hybrids of Eucoreosma section
Abstract |

Resistance to fungal diseases of interspecific currant hybrids of Eucoreosma section

T. Siksnianas, V. Stanys, G. Stanienė, C. Bobinas,A. Sasnauskas and R. Rugienius

Lithuanian Institute of Horticulture, Babtai LT-4335, Kaunas distr., Lithuaniae-mail: a.sasnauskas@lsdi.lt

Abstract:

Interspecific hybridisation in genus Ribes is one of the most effective methods fordeveloping resistant cultivars. Plants of R. nigrum x R. pauciflorum, R. nigrum x R. ussuriense, R. nigrum x R. Janczewskii (F1) were obtained directly after interspecifichybridization of currant. Hybrids of R. nigrum × R. americanum and R. americanum x R. nigrum (F1 – F3) were obtained after interspecific hybridization and embryo rescue in vitro.Fertile plants were found in all crosses. 20.0–52.3% of hybrids in F1 were resistant to powderymildew. In crosses of R. nigrum x R. pauciflorum, R. nigrum x R. Janczewskii 2–5% of plants were undamaged by Septoria leaf spot. Plant fertility of hybrids R. nigrum × R. americanum and R. americanum x R. nigrum was very low in F1 and increased in F2 and F3. There wereresistant plants in all families of hybrids obtained by reciprocal crosses, but resistance level of hybrids with R. americanum cytoplasm was considerably higher. The resistance to fungal diseases of some hybrids in F3 generation was higher than R. nigrum and equal to R. americanum.

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371-378 A. Sliesaravičius, J. Pekarskas, V. Rutkovienė and K. Baranauskis
Grain yield and disease resistance of winter cereal varieties and application of biological agent in organic agriculture
Abstract |
Full text PDF (119 kB)

Grain yield and disease resistance of winter cereal varieties and application of biological agent in organic agriculture

A. Sliesaravičius, J. Pekarskas, V. Rutkovienė and K. Baranauskis*

Lithuanian University of Agriculture, Studentų 11, Lt-53361, Akademija,Kaunas distr., Lithuania
*Lithuanian Institute of Horticulture, Babtai, LT-54333 Kaunas distr., Lithuania;e-mail: algis.Sliesaravicius@lzuu.lt

Abstract:

Field trials with different varieties of winter wheat, rye barley and triticale were carried out at the Agroecology Center of the Lithuanian University of Agriculture from 2003-2005. The biological agent biojodis was tested. The winter wheat varieties ‘Baltimor’ and ‘Residence’ were found to be the most resistant to Septoria tritici (leaf blotch. The biological agent biojodis increased wheat grain yield for separate varieties by 0.38 – 0.97 t ha-1. No significant differences in disease resistance were found among the triticale and rye varieties tested. Research on the biological agent biojodis revealed that this agent reduced the incidence of fungi in the grain of the winter wheat variety ‘Širvinta 1’, thus it could diminish the number of mycromicetes species and the fungal infection level.The grain untreated wtith biojodis was found to be infected with 4 fungi species(Aspergillus oryzae, Fusarium nivale, Fusarium poae, Mycelia sterilia), where the infection level reached 9.0×103 cfu (colony forming unit), whereas the grain treated with the agent at a rate of 2 l t-1 was found to be infected with 2 species of fungi (Fusarium poae, Fusarium sporotrichiodes) at 5.5×103 cfu (colony forming unit) infection level.

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379-383 R. Smatas
The occurrence and control of aphids and thrips in winter triticale
Abstract |
Full text PDF (128 kB)

The occurrence and control of aphids and thrips in winter triticale

R. Smatas

Lithuanian Institute of Agriculture, Instituto aleja 1, Akademija, Kedainiai dist., LT58344,Lithuania; remigijus@lzi.lt

Abstract:

Studies were carried out at the Lithuanian Institute of Agriculture during the period 2002–2004. Contact and systemic insecticides were used for pest control in winter triticale. Pesticide application timing was determined according to the threshold of harmfulness of thrips and aphids. In our investigation we used as the threshold of thrips’ harmfulness, 1–2 pests per stem, and for aphids, 5–10 pests per stem. Our results suggest that thrips and aphids were the main pests occurring in winter triticale crops during the experimental years. The occurrence of thrips was more intensive in 2002 and 2003 than in 2004. The occurrence of aphids was the most intensive in 2002, less intensive in 2004. Almost no aphids were found in 2003. The appearance of aphids in 2004 was later compared with that in 2002. Both insecticides reduced the occurrence of thrips and aphids. The winter triticale grain yield was higher in the plots applied with insecticides.

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385-388 P. Sooväli and A. Bender
The occurrence of powdery mildew on crested hairgrass in different growing conditions
Abstract |

The occurrence of powdery mildew on crested hairgrass in different growing conditions

P. Sooväli and A. Bender

Jõgeva Plant Breeding Institute, 48309 Jõgeva, Estonia; e-mail: pille.soovali@jpbi.ee

Abstract:

Crested hairgrass (Koeleria gracilis Pers., syn. K. macrantha (Ledeb.) is classed as a good turfgrass. A first cultivar ‘Ilo’, released by the Jõgeva Plant Breeding Institute was entered into the Estonian Variety List in 1997. Seed production agrotechnics of crested hairgrass cultivar ‘Ilo’ was studied in field experiments at the Jõgeva PBI in 2001–2005. It has been recognized that the incidence and severity of disease level and seed yield losses are influenced by pathogens and weather. For four seasons the severity of the occurrence of powdery mildew (Blumeria graminis DC.) was investigated in these field trials. Disease infection was scored by visual assessment of full plants at shooting, flowering and seed ripening stages and at post–harvest re-growth on a 5–point scale. Infection was more intensive in the flowering stage: 2.6 points (2002), 3.0 (2003) and 3.7 (2004). Infection at post–harvest re-growth was assessed at 3.1 points in 2002.

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389-392 P. Sooväli, M. Koppel and H. Nurmekivi
Optimization of chemical disease control in spring wheat
Abstract |

Optimization of chemical disease control in spring wheat

P. Sooväli, M. Koppel and H. Nurmekivi

Jõgeva Plant Breeding Institute, 48309 Jõgeva, Estonia; e-mail: pille.soovali@jpbi.ee

Abstract:

Septoria leaf blotch complex (Septoria tritici and Septoria nodorum) and powdery mildew (Blumeria graminis) are common foliar diseases of spring wheat in Estonia. This paper reports results of multi-site field experiments performed on spring wheat varieties Tjalve and Munk during 2003–2004 in Estonia. Fungicides Falcon 460 EC and Opera were used in full and reduced doses of one or split applications. The aim of the current study was to obtain efficient disease control and to identify the impact of fungicide application on yield at the time of fungicide application. The biological efficiency of fungicides was assessed based on disease scorings made until growing stages 75–77. The trial results show that biologically and economically effective control of wheat diseases could be achieved with timely use of lowered fungicide doses. Spraying at growing stages 41–55 will often be enough to achieve good control of serious attacks by Septoria.

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393-396 A. Stankevičienė and J. Varkulevičienė
Pathogenic micromycete species functioning in the rhizosphere of sick pot-plants growing in peat substrate
Abstract |

Pathogenic micromycete species functioning in the rhizosphere of sick pot-plants growing in peat substrate

A. Stankevičienė and J. Varkulevičienė

Kaunas Botanical Garden of Vytautas Magnus University, Ž. E. Žilibero 6, LT 46324,Kaunas, Lithuania; e-mail: a.stankeviciene@bs.vdu.lt

Abstract:

During 1994–2005 investigations were carried out on 53 taxa of ornamental pot-plants belonging to 26 cultivars, 48 species, 35 genera, and 15 families. From the rhizosphere of 43% plants kept under unfavourable growth conditions plant pathogens were isolated from the following genera: Fusarium (8 species), Pythium (6 species), Verticillium (5) and Sclerotinia sclerotiorum, Thielaviopsis basicola, Rhizoctonia solani. Simultaneously on each sick plant rhizosphere there functioned several species of pathogenic micromycetes: from Aechmea fasciata – Fusarium equiseti, F. oxysporum and Pythium irregulare; from Dieffenbachia seguine – Fusarium oxysporum, Pythium aristosporum, P. debaryanum, from Dracaena fragrans – Fusarium oxysporum and Pythium.irregulare; from Dracaena marginata – Fusarium oxysporum and Pythium flavoense; from Alocasia x amazonica – Fusarium oxysporum and Verticillium nubilum.

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397-401 S. Supronienė, O. Auškalnienė, Z. Dabkevičius and A. Mankevičienė
The effects of growth regulators on spring barley (Hordeum vulgare L.) morphological indicators and grain contamination with fungi and mycotoxins
Abstract |
Full text PDF (140 kB)

The effects of growth regulators on spring barley (Hordeum vulgare L.) morphological indicators and grain contamination with fungi and mycotoxins

S. Supronienė, O. Auškalnienė, Z. Dabkevičius and A. Mankevičienė

Lithuanian Institute of Agriculture, Instituto str. 1, LT–58344 Akademija, Kedainiu distr.,Lithuania; e-mail: skaidre@lzi.lt, ona@lzi.lt,

Abstract:

The effects of growth regulators Modus 250 EC (trinexapac–ethyl 250 g l-1) and Cerone 480 (etefon 480 g l-1) on the morphological characteristics of the spring barley varieties Henni and Luokė and on grain contamination with fungi and mycotoxins were studied at the Lithuanian Institute of Agriculture in 2004 and 2005.Spring barley was sprayed with the retardant Modus at growth stages 32–33 BBCH andwith the retardant Cerone at – 39–43 BBCH. Plant morphological measurements were made before harvesting. Percent of internal grain contamination with fungi was determined. The concentrations of the mycotoxins deoxynivalenol (DON), T-2 toxin and zearalenone (ZEN) in grain were measured by ELISA method, using Neogen diagnostic mycotoxin determination tests.The retardants reduced plant height from 66.0 to 58.0 cm, length of the last node from19.4 to 17.9 cm for the variety Henni, and from 74.1 to 63.8 cm, and from 22.4 to 16.9 cm, respectively, for the variety Luokė compared with the unsprayed plants.The content of Fusarium-affected grain in the retardant-sprayed and not appliedtreatments was similar, however, Fusarium avenaceum (Fr.) Sacc was more prevalent in the barley sprayed with retardants. F. avenaceum, F. sporotrichioides Sherb., F. poae (Peck) Wollenw, F. tricinctum (Corda) Sacc., F. culmorum (W. G. Smith) Sacc. dominated in the grain samples in 2005.The contents of DON, ZEN and T-2 toxin determined were low, however, higher contentswere identified for barley sprayed with the retardants.

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403-406 E. Survilienė and E. Dambrauskienė
Effect of different active ingredients of fungicides on Alternaria spp. growth in vitro
Abstract |

Effect of different active ingredients of fungicides on Alternaria spp. growth in vitro

E. Survilienė and E. Dambrauskienė

Lithuanian Institute of Horticulture, LT-54333 Babtai, Kaunas distr., Lithuania;e-mail: e.surviliene@lsdi.lt

Abstract:

The impact of different active ingredients of fungicides on the development of Alternaria species in vitro was estimated by using Amistar 250 SC (azoxystrobin), Signum 334 WG (boscalid, pyraclostrobin), Zato 50 WG (trifloxystrobin) and Folicur 250 EW (tebuconazol). The growth colonies of micromycetes Alternaria alternata (isolated from Thymus vulgaris, Levisticum officinale), Alternaria alternata, Alternaria brassicae (isolated from Brassica oleracea convar. capitata var. alba) and Alternaria dauci (isolated from Daucus carota) were tested on the potato dextrose agar medium with additions of fungicides. All tested fungicides showed sufficient inhibitory activity on the growth Alternaria spp. colonies, , which decreased on average from 94-25% over 21 days in comparison with the control.

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407-411 L. Talgre, E. Lauringson, V. Vasar and H. Roostalu
The effect of pests on the yield and economical value of cereals
Abstract |

The effect of pests on the yield and economical value of cereals

L. Talgre¹, E. Lauringson¹, V. Vasar² and H. Roostalu¹

¹ Estonian University of Life Sciences, Institute of Agricultural and Environmental Sciences,Kreutzwaldi St. 64, 51014 Tartu, Estonia; tel. +372-7-313522, e-mail: liina.talgre@emu.ee
² Research Centre EVIKA Tallinn University of Technology,Teaduse 6a, 75501 Saku, Harjumaa, Estonia

Abstract:

Abstract: One of the most serious factors that limit the yield of cereal crops is fungal diseases. In the Estonian University of Life Sciences field trials with various spray programs of fungicides were conducted to determine the efficacy and economical value of different pesticide combinations. The spray programs with full dose rates of fungicides were not always economically justified nor were the multiple application systems. Yield increase up to 35% in spring wheat and up to 33% in barley was achieved when the timing of pesticide application was optimal and the crop stand was good and had high yield potential. The dominating disease in spring wheat on both trial years was Septoria spp. The best control was provided by fungicide Opera (active ingredients pyraclostrobin and epoxiconazole). Barley was infected mostly by Pyrenophora teres. The economical efficiency of disease control depended primarily on the weather conditions, crop stand and the quality of cereals. Application of pesticides was economically more effective in spring wheat. Therefore multiple application programs with more expensive pesticides can be recommended. The dense crop stand and an environment favorable for distribution of diseases increased the efficacy of fungicides on barley.

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413-416 K. Tiirmaa, N. Univer and T. Univer
Evaluation of apple cultivars for scab resistance in Estonia
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Evaluation of apple cultivars for scab resistance in Estonia

K. Tiirmaa, N. Univer and T. Univer

Polli Horticultural Research Centre of the Institute of Agricultural and Environmental Sciences,Estonian University of Life Science, 69104Karksi-Nuia, Estonia; e-mail: krista.tiirmaa@emu.ee

Abstract:

In the economic sense, apple scab caused by Venturia inaequalis (Cke.) Wint is a most dangerous disease of apple trees in Estonia. Control of the disease is of major concern to apple growers and lack of control results in unmarketable fruit. Therefore it is very important for growers to know the apple scab resistance of the cultivars in the orchard, since the most susceptible ones should be avoided. Cultivating disease-resistant varieties seems to be an optimum alternative to chemical control. In 2002, 2003 and 2005 susceptibility to apple scab of 102 apple cultivars was evaluated in the apple collection garden at the Polli Horticultural Research Centre. The purpose of the study was to identify cultivars in the Polli apple collection that have good scab resistance. About 30% of the cultivars assessed had very little or no disease incidence. Among thegenetically resistant cultivars were ‘Imrus’, ‘Chistotel’, ‘Orlovim’, ‘Orlovskij Pioner’, ‘Pamjat Isajeva’, ‘Pervinka’, ‘Slavyanin’, ‘Liberty’ and ‘Freedom’. Many old and local cultivars showed low incidence of disease. Rapid development of the infection was recorded on five cultivars: ‘Borovinka Ananasnaya’, ‘Pirja’, ‘Maikki’, ‘Mantet’, and ‘Red Atlas’.

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417-420 L. Urbanavičienė, D. Valiūnas and R. Jomantienė
Detection of aster yellows group (subgroup 16SrI-B) phytoplasma in oats based on nested PCR and RFLP in Lithuania
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Detection of aster yellows group (subgroup 16SrI-B) phytoplasma in oats based on nested PCR and RFLP in Lithuania

L. Urbanavičienė, D. Valiūnas and R. Jomantienė

Institute of Botany, Plant Virus Laboratory,Žaliųjų Ežerų 49, LT-08406 Vilnius, Lithuania; e-mail: urbanala@botanika.lt

Abstract:

Phytoplasma strains were detected in oats (Avena sativa L.) in Lithuania exhibiting disease symptoms of stunting, sterile, deformed and yellow spikes. A phytoplasma-characteristic 1.8 kb and 1.2 kb rDNA PCR products were amplified from DNAs of all diseased but not healthy oat plants tested, using phytoplasma universal primer pairs P1/P7 and R16F2n/R16R2 confirming that symptomatic plants were infected by phytoplasma. Phytoplasma was termed oat stunt (OatSt). Restriction fragment length polymorphism (RFLP) analysis of amplified 16S rDNA indicated that diseased oats were infected by phytoplasma belonging to the group 16SrI (aster yellows, AY, group) and subgroup 16SrI-B. This is the first report of phytoplasma belonging to 16SrI (aster yellows) group and 16SrI-B phytoplasma subgroup identified in oat plants.

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421-425 N. Uselis, A. Valiuškaitė and L. Raudonis
Incidence of fungal leaf diseases and phytophagous mites in different strawberry cultivars
Abstract |

Incidence of fungal leaf diseases and phytophagous mites in different strawberry cultivars

N. Uselis, A. Valiuškaitė and L. Raudonis

Lithuanian Institute of Horticulture, Babtai, Kaunas distr., LT-54333,Lithuania; e-mail: n.uselis@lsdi.lt

Abstract:

The incidence of fungal leaf diseases, phytophagous mites and productivity of strawberry cultivars ‘Saulenė’, ‘Honeoye’, ‘Kent’, ‘Elkat’, ‘Polka’, ‘Dangė’, ‘Senga Sengana’, ‘Pegasus’, ‘Bogota’ and ‘Pandora’ was investigated in 2004–2005 under field conditions at the Lithuanian Institute of Horticulture.The lowest incidence by common leaf spot (Mycosphaerella fragariae (Tul.) Sacc) wasrecorded on Dangė’, ‘Elkat’ and ‘Pegasus’. Disease prevalence ranged on average from 43–46 % and disease intensity from 14–15.7%. The most common white leaf spot was on ‘Honeyoe’ and ‘Senga Sengana’. ‘Elkat’ and ‘Polka’ were the most damaged (disease prevalence was 68–69% and intensity 36–46%) by leaf scorch (Marssonina potentilae Desm. Magn.), while the lowest incidence of leaf scorch was recorded on ‘Bogota’. The incidence of diseases varied depending on meteorological conditions during 2004–2005.The lowest infestation by strawberry mite (Tarsonemus pallidus Banks.) was recorded on‘Bogota’ and ‘Kent’. Moderately infested were ‘Honeoye’, ‘Saulenė’,‘Pandora’, ‘Senga Sengana’ and highly infested, ‘Pegasus’. Low infestation by two-spotted spider mites (Tetranychus urticae Koch) were ‘Bogota’, ‘Pandora’ and ‘Saulenė’, moderately – ‘Kent’ and ‘Honeoye’; the most common two-spotted spider mites were found on ‘Pegasus’.The study showed that ‘Saulenė’, ‘Pandora’, ‘Senga Sengana’, ‘Honeoye’, ‘Polka’,‘Elkat’ and ‘Dangė’ were highly productive, ranging from 11 to 17 t ha-1. The productivity of ‘Pegasus’ was 9 t ha-1. Cultivars ‘Bogota’ and ‘Kent’ were averagely productive (6 – 7 t ha-1) .

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427-431 A. Valiuškaitė, N. Kviklienė, D. Kviklys and J. Lanauskas
Post-harvest fruit rot incidence depending on apple maturity
Abstract |

Post-harvest fruit rot incidence depending on apple maturity

A. Valiuškaitė, N. Kviklienė, D. Kviklys and J. Lanauskas

Lithuanian Institute of Horticulture, Babtai, Kaunas distr., LT-54333,Lithuania; e-mail: a.valiuskaite@lsdi.lt

Abstract:

The effect of fruit maturity on apple storage ability and rot development wasinvestigated in 2003–2004 at the Lithuanian Institute of Horticulture. Two apple cultivars ‘Ligol’ and ‘Lodel’ on M.26 rootstock were tested. Fruits were harvested 5 times at weekly intervals and were stored for six months in cold storage. Maturity index was calculated at each harvesting.Fruit quality parameters and rot incidence were evaluated after 90, 150 and 180 days ofstorage. While in storage ‘Lodel’ apple rot was caused by Monilinia sp., Gloeosporium spp., Penicillium spp., Alternaria spp. and Botrytis sp. Cv. ‘Ligol’ apples were infected by Monilinia sp., Gloeosporium spp. and Penicillium spp. Both tested cultivars were mostly infected by fungus of Gloeosporium genus. Cv. ‘Lodel’ was more sensitive to fungal rots.The time and intensity of rot incidence depended on cultivar, harvest date and climaticcondition during the vegetation. More rot injuries were detected on apples picked later. A significantly smaller number of rotten apples was recorded in apples picked at optimum maturity. Cold and wet weather during the ripening period determined an earlier and significantly higher occurrence of fungus during storage.

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433-436 I. Vanaga, J. Gurkina, O. Treikale, I. Priekule and J. Pugacova
Influence of Heracleum sosnowskyi control measures on weed diversity in agricultural fields in Latvia
Abstract |

Influence of Heracleum sosnowskyi control measures on weed diversity in agricultural fields in Latvia

I. Vanaga, J. Gurkina, O. Treikale, I. Priekule and J. Pugacova

Latvian Plant Protection Research Centre, Lielvardes iela 36/38, Riga, LV1006, Latvia;e-mail: ineta.vanaga@laapc.lv

Abstract:

Abstract: In a field infested with Heracleum sosnowskyi, plots were cultivated by disc harrow or ploughed in 2003 and then sown with one of two grass mixtures. Half of the grass plots were sprayed once with a herbicide containing MCPA, fluroxypyr and chlorpyralid; the other half were cut 3 times with a hand mower. In 2004 a similar trial was established after an early season application of glyphosate to control Elymus repens and the soil had been deep ploughed. The most effective control of H. sosnowskyi and E. repens was obtained by glyphosate application after spring regrowth followed by deep ploughing. This treatment did not adversely affect either numbers of dicotyledonous species or numbers of dicotyledonous plants that grew in the sown grass swards. Ploughing gave better control of H. sosnowskyi and E. repens than disc harrowing and provided better seedbeds for sward establishment. Ploughing also increased the numbers of dicotyledonous species and plants compared to disc harrowing. Chemical weed control reduced diversity and plant numbers, but weed control by cutting did not.

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437-440 M. Vasinauskienė, J. Radušienė, I. Zitikaitė and E. Survilienė
Antibacterial activities of essential oils from aromatic and medicinal plants against growth of phytopathogenic bacteria
Abstract |

Antibacterial activities of essential oils from aromatic and medicinal plants against growth of phytopathogenic bacteria

M. Vasinauskienė¹, J. Radušienė¹, I. Zitikaitė¹ and E. Survilienė²

¹Institute of Botany, Žaliųjų ežerų 49, LT–08406 Vilnius, Lithuania; e-mail:milda@botanika.lt
²Lithuanian Institute of Horticulture, LT–4335 Babtai, Kaunas distr.; e-mail:e.surviliene@lsdi.lt

Abstract:

In search for alternative ways of plant disease control, essential oils from aromatic and medicinal plants were studied for their antibacterial properties. In a preliminary evaluation, steam-distilled essential oils from oregano, sweet-flag, caraway, peppermint, common, fern leaf and willow-leaved yarrow field accessions were investigated against growth of phytopathogenic bacteria. The disc-diffusion method was used for the assessment of inhibitory effects of the essential oils. The antibacterial activity tests were conducted in vitro. Essential oil from oregano was found to have the strongest inhibitory effect against tested phytopathogenic bacteria. Less antibacterial effect was found with essential oils from caraway, peppermint, fern-leaf and willow-leaved yarrow,, while the oils from common yarrow and sweet-flag manifested no inhibition. Xanthomonas vesicatoria 67 was the most sensitive to essential oils tested. A weak antibacterial activity was found against some Pseudomonas spp. strains and Erwinia carotovora subsp. carotovora bacteria.

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441-445 A. Velykis and A. Satkus
Influence of crop rotations and reduced tillage on weed population dynamics under Lithuania’s heavy soil conditions
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Influence of crop rotations and reduced tillage on weed population dynamics under Lithuania’s heavy soil conditions

A. Velykis and A. Satkus

Joniskelis Research Station of the Lithuanian Institute of Agriculture, Joniskelis, LT-3930,Pasvalys District, Lithuania; tel.fax.: 370-71-38224; e-mail: joniskelio_lzi@post.omnitel.net

Abstract:

Experiments to study the weed population dynamics in cereals, under conditions of expanded winter crop proportion in rotations and reduced soil tillage, were carried out on a clay loam Gleyic Cambisol at Joniskelis Research Station of the Lithuanian Institute of Agriculture. Variations were as follows: A. Crop rotations with different proportions of winter and spring crops: 1. Without winter crops; 2. Winter crops 25%; 3. Winter crops 50%; 4. Winter crops 75%; 5. Winter crops 100%, growing annual and perennial grasses, spring and winter wheat, triticale and barley; B. Soil primary tillage systems: 1. Conventional (ploughing). 2. Reduced (ploughing after grasses, ploughless after cereals) were investigated. The results of investigations show that increasing the proportion of winter crops in rotations during a four-year rotation resulted in reduction of perennial weeds in the cereal crops; however, the content of annual weeds was higher. The prevalent annual and perennial (14.7% of total number) weeds spread in spring cereals (wheat, triticale, barley) were more dangerous to crops than to the weed species found in winter cereals. Perennial weeds amounted to only 6.9% in winter cereals. The perennial weeds recorded in cereals were only 3.9-18.0% at the beginning of crop growing season, depending on crop rotation, however before crop harvest they reached 24.2−52.1%. When growing cereals with reduced soil tillage, the number of perennial weeds was 2.4 times higher; annual weeds, somewhat lower, and the air-dried biomass of all weeds was 44.5% higher compared to conventional tillage.

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447-450 E. Veromann, A. Luik and R. Kevväi
The impact of field edges on the incidence of Meligethes aeneus Fab. larvae and their parasitisation in spring and winter oilseed rape
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The impact of field edges on the incidence of Meligethes aeneus Fab. larvae and their parasitisation in spring and winter oilseed rape

E. Veromann, A. Luik and R. Kevväi

Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,Kreutzwaldi St. 64, EE51014 Tartu, Estonia; e-mail: eve.veromann@loodusfoto.ee

Abstract:

The occurrence of Meligethes aeneus larvae and their parasitism rate was studied at the edges and in the centres of commercial spring and winter oilseed rape fields in Estonia. Insecticides were used in spring oilseed rape but not in winter oilseed rape fields. Significantly more larvae were found at the field edges than in centres of both crops, but they were more abundant in winter oilseed rape. The larval parasitism rate was significantly greater at field edges than in centres only in winter rape; in spring oilseed rape parasitism was more evenly distributed. But there were no differences in pollen beetle parasitisation rates between crops.

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451-455 R. Virbickaite, A. P. Sirvydas, P. Kerpauskas and R. Vasinauskiene
The comparison of thermal and mechanical systems of weed control
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The comparison of thermal and mechanical systems of weed control

R. Virbickaite, A. P. Sirvydas, P. Kerpauskas and R. Vasinauskiene

Lithuanian University of Agriculture, Department of Heat and BiotechnologyEngineering, Kauno r. Studentu 15, LT 53356, Lithuania; tel: (+370) 37 75 23 17;fax: (+370) 37 75 23 24; e-mail: v.rasaa@gmail.com

Abstract:

In ecological farming weed control after sowing time is pursued by mechanical, and recently, by thermal means. In thermal weed control both the surface of the soil and the roots of cultural plants remain undisturbed, however, the l cultured plant experiences a thermal shock. This combination of factors has a positive influence on productivity. Data for the comparable efficiency of thermal and mechanical weed control research results in 2001–2003 and 2005 are presented. 16 weeds were destroyed. Thermal weed control for annual weeds is 22.5% more effective in comparison with the mechanical method, however the latter is 32% more effective for perennial weeds.

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457-460 K. Voolma and I. Sibul
The effect of collecting fluid on the catch results of Hylobius abietis in pitfall traps
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The effect of collecting fluid on the catch results of Hylobius abietis in pitfall traps

K. Voolma and I. Sibul

Institute of Forestry and Rural Engineering, Estonian University of Life Sciences,Kreutzwaldi St. 5, 51014 Tartu, Estonia; e-mail: kaljo.voolma@emu.ee

Abstract:

Two different collecting and killing agents – ethylene glycol and water – were tested in pitfall traps used for trapping adults of the large pine weevil, Hylobius abietis (L.) in clear-felled areas of a massive pine-dominated forest in southern Estonia. The traps were baited with a blend of turpentine and ethanol and filled with a 50%-water-solution of ethylene glycol or clean water without any ingredients and were established in fresh or one-year-old clear-cuttings. During the two-year experiment, 5952 individuals of the pine weevil were caught, of which 50.5% were female and 49.5% male. No significant differences were observed either in the total catch results or in the sex ratios of the pine weevil between the traps filled with ethylene glycol or water.

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461-464 A. Wagner, W. Michalek and A. Jamiolkowska
Chlorophyll fluorescence measurements as indicators of fusariosis severity in tomato plants
Abstract |

Chlorophyll fluorescence measurements as indicators of fusariosis severity in tomato plants

A. Wagner¹, W. Michalek² and A. Jamiolkowska¹

¹Department of Plant Protection and Quarantine, Agricultural University,Leszczynskiego 7, 20-069 Lublin, Poland; e-mail: annawagner@poczta.onet.pl
²Department of Plant Physiology, Agricultural University, Akademicka 15,20-950 Lublin, Poland; e-mail: wladyslaw.michalek@ar.lublin.pl

Abstract:

In these experiments the pathogenicity of Fusarium oxysporum populations was investigated. Disease index for inoculated plants was compared to chlorophyll fluorescence parameters measured with the fluorometer PAM. For most of the isolates of higher pathogenicity, the disease index was correlated with the decrease of photosynthetic activity of plants. However, in some cases the damage to the photosystem was more severe than external disease symptoms indicated, suggesting that chlorophyll fluorescence measurements might be helpful in early evaluation of the severity of F. oxysporum.

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465-470 I. H. Williams
Integrating parasitoids into management of pollen beetle onoilseed rape
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Integrating parasitoids into management of pollen beetle onoilseed rape

I. H. Williams

Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ,UK

Abstract:

Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ,UK Hymenopterous parasitoids can exert substantial natural control on oilseed rape pest populations. This paper reviews recent work at Rothamsted Research on integrating parasitoids into the management of rape pests. It focuses on the pollen beetle, Meligethes aeneus, and its two larval endoparasitoids, Phradis interstitialis and Tersilochus heterocerus. Strategic research on the behavioural ecology of the parasitoids is described. Phradis interstitialis was shown to use upwind anemotaxis to locate the crop. Within-field spatio-temporal distributions of M. aeneus adults and larvae were complex with irregular patterns of aggregation. Whereas P. interstitialis was closely associated temporally and spatially with the distribution of its host, T. heterocerus larvae were as abundant outside dense host patches as within them and showed little pattern. Both parasitoid species overwinter in the soil of the rape field and emerge the following spring. Post-harvest soil cultivations, particularly ploughing, can reduce their survival, whereas non-inversion tillage is less harmful. Phenological studies show that pyrethroid applications during flowering threaten parasitoid populations. Implications of the research for conservation biological control and the development of more environmentally-friendly crop protection is discussed.

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471-474 I. Zitikaitė and J. Staniulis
The use RT-PCR for detection of viruses infecting cucumber
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The use RT-PCR for detection of viruses infecting cucumber

I. Zitikaitė and J. Staniulis

Institute of Botany, Žaliųjų Ežerų, 49, LT-08406, Vilnius, Lithuania;e-mail: izitika@botanika.lt

Abstract:

Cucumber plants exhibiting virus-like disease symptoms were collected in various gardens and greenhouses in Lithuania. Viral diseases were expressed by symptoms of mosaic-mottling, yellow ringspots and vein necrosis of leaves. Growth and fruiting of plants were reduced. Results of the identification of viruses detected in cucumbers by the RT-PCR technique are presented here. Identification of causal agents was based on cDNA amplified product size in PCRs using virus-specific oligonucleotides. From cucumbers with various virus-like symptoms 400, 499 and 300 bp DNA fragments were amplified. They are characteristic for Cucumber mosaic virus (CMV), Tomato ringspot virus (ToRSV) and Tobacco necrosis virus (TNV), respectively, and confirm cucumber infection by these viruses.

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475-478 M. Žižytė, J. Staniulis and I. Zitikaitė
Identification of Beet necrotic yellow vein virus isolate detected in Lithuania
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Identification of Beet necrotic yellow vein virus isolate detected in Lithuania

M. Žižytė, J. Staniulis and I. Zitikaitė

Institute of Botany, Žaliųjų Ežerų 49, LT-08406 Vilnius, Lithuania;e-mail: marija.zizyte@botanika.lt

Abstract:

Sugar beet plants with rhizomania symptoms in their roots were detected in the central region of Lithuania. The study was undertaken to ascertain the possible presence of beet necrotic yellow vein virus (BNYVV) in the rootlets. DAS-ELISA, lateral flow tests, electron microscopy and mechanical transmission to indicator plantsconfirmed the presence of BNYVV. BNYVV was detected in leaf tissue of indicator plants with local lesions, and products of the expected size were amplified by RT-PCR, immunocapture RT-PCR (IC-RT–PCR) and nested PCR (nPCR) (500 bp for RT-PCR and 326 bp for nPCR). This is the second location where the presence of BNYVV quarantine pathogen in Lithuania has been proved.

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