Tag Archives: weed

xxx F.C. Garcia, A.J.P. Albrecht, L.P. Albrecht, J.R. Barbosa, A.F.M. Silva, W.F. Larini, G. Moreno and A.A.M. Barroso
Efficacy of pre-emergence herbicides in controlling Sumatran fleabane (Conyza sumatrensis) in the off-season
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Efficacy of pre-emergence herbicides in controlling Sumatran fleabane (Conyza sumatrensis) in the off-season

F.C. Garcia¹, A.J.P. Albrecht², L.P. Albrecht², J.R. Barbosa¹, A.F.M. Silva³*, W.F. Larini⁴, G. Moreno² and A.A.M. Barroso⁴

¹State University of Maringá (UEM), Department of Agronomic Sciences,
Estrada da Paca, BR87502-970 Umuarama, PR, Brazil
²Federal University of Paraná (UFPR), Department of Agronomic Sciences, R. Pioneiro 2153, BR85950-000 Palotina, PR, Brazil
³Crop Pesquisa, Linha Bem-ti-vi, BR85955-000 Maripá, PR, Brazil
⁴UFPR, Department of Crop Science and Plant Health, R. dos Funcionários 1540, Curitiba, PR, Brazil
*Correspondence: afmoreirasilva@alumni.usp.br

Abstract:

Pre-emergence herbicides can be effective in controlling Sumatran fleabane
(Conyza sumatrensis [Retz.] E.Walker) at soybean and other crops. The goal was to evaluate the effectiveness of sulfentrazone/diuron, imazethapyr/flumioxazin, flumioxazin, diclosulam, s-metolachlor, imazethapyr, clomazone and imazapic/imazapyr in controlling Sumatran fleabane for application in the off-season before soybean planting. Three experiments were conducted in the off season, with 9 treatments. The control of Sumatran fleabane was evaluated at 28, 42 and 49 days after application (DAA), at 49 DAA was performed counting of plants per m². In experiment 1, the worst performance was found for s-metolachlor (58.3% final control), in a situation of lower emergence flow of Sumatran fleabane, with equivalence for the other herbicides. In experiments 2 and 3, with greater emergence flow of Sumatran fleabane, clomazone efficacy stood out (≥ 86.3% final control). A micro-encapsulated formulation of clomazone was used, which causes greater intoxication to this weed due to its slow release into the soil, and presents less loss to the environment. In conditions of lower emergence of Sumatran fleabane, sulfentrazone/diuron, imazethapyr/flumioxazin, flumioxazin, diclosulam, imazethapyr, clomazone and imazapic/imazapyr were effective in controlling it. Even in this condition, s-metolachlor was not effective in controlling Sumatran fleabane. The application of clomazone was effective in controlling Sumatran fleabane in the three experiments. Clomazone is characterized as an important herbicide for use in the off season in the management of this weed before soybean sowing.

Key words:

clomazone, early management, Erigeron sumatrensis, weed, weed emergence

592-597 L. Talgre, V. Eremeev, E. Mäeorg and A. Luik
Diversified cropping systems for promoting the beneficial insects – ground beetles (Coleoptera: Carabidae)
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Diversified cropping systems for promoting the beneficial insects – ground beetles (Coleoptera: Carabidae)

L. Talgre*, V. Eremeev, E. Mäeorg and A. Luik

Estonian University of Life Sciences, Institute of Institute of Agricultural and Environmental Sciences, Kreutzwaldi 5, EE51006 Tartu, Estonia
*Correspondence: liina.talgre@emu.ee

Abstract:

In agro-ecosystems ground beetles – carabids (Coleoptera: Carabidae) are important as generalist predators of invertebrate pests and weed seeds and as prey for larger animals. This way they contribute to biodiversity and influence the most important ecological processes. Impacts of crop management practices on the carabids are not well described. Carabids were studied in winter wheat which is one crop in the rotation experiment (barley undersown with clover-clover-winter wheat-pea-potato). Carabids were collected with pitfall trap during one week at the end of June 2022. In laboratory, their species was identified. Trapping of carabids during the spiking phase of winter wheat has shown significant differences in carabids activity-density and diversity depending on five different cropping systems. In two conventional systems where pesticides were used the number of carabids was two times smaller in comparison with three organic systems. Activity-density and diversity of carabids was significantly higher in all organic systems and especially in Org II system where winter cover crops and composted manure where used for rotation diversification. The Shannon–Wiener index values, which takes into account the number of species and their relative abundance were 1.24–1.53 in conventional systems, but higher in diversified organic systems (1.60–1.78). Only in organic systems Org I and Org II there were very rare species present, like Acupalpus meridianus (Linnaeus) and Microlestes minutulus (Goeze). In diversified organic systems the higher activity-density and abundance of carabids could be explained by the diverse plant community as possible source for better food and microclimatic conditions.

Key words:

conventional cropping, organic cropping, pesticides, weed, winter cover crops

1380–1387 V. Osadčuks, A. Kostromins, A. Pecka, V. Koteļeņecs and J. Jaško
Experimental efficiency evaluation of 445 nm semiconductor laser for robotized weed control applications
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Experimental efficiency evaluation of 445 nm semiconductor laser for robotized weed control applications

V. Osadčuks¹*, A. Kostromins², A. Pecka², V. Koteļeņecs³ and J. Jaško³

¹Latvia University of Life Sciences and Technologies, Faculty of Engineering, Čakstes blvd. 5, LV-3001 Jelgava, Latvia
²Latvia University of Life Sciences and Technologies, Faculty of Information Technologies, Liela street 2, LV-3001, Jelgava, Latvia
³Latvia University of Life Sciences and Technologies, Institute for Plant Protection Research “Agrihorts”, Paula Lejina iela 2, LV-3004 Jelgava, Latvia
*Correspondence: vtl@tvnet.lv

Abstract:

Robotized weed control is one of perspective approaches for decreasing ecological impact of farming. Although current level of technology development allows robotized weed control to be economically reasonable only in specific applications, it is only a matter of time to introduce them in full-scale industrial farming. In general terms weed control using agricultural robots consist of two parts: recognition and spatial localization of weeds (distinguishing them from crops) and precision application of some kind of growth limiting activity. Recognition and localization is usually carried out using computer vision solutions (image filtering and transformations, artificial neural networks etc.). Growth limiting in its turn is performed by mechanical, precise chemical, thermal, cryogenic or other means. This article covers application of laser radiation for thermal destruction of unwanted plant canopies. In most cases CO₂ type lasers with 10.6 μm wavelength is used as they are affordable and they are applicable to use with plant biomass due to their spectral characteristics. Drawbacks of CO₂ lasers are low efficiency, size, weight and complex maintenance. In recent years relatively powerful short-wavelength semiconductor lasers have became broadly available on market. Light absorption of healthy green leaves is much better in blue-UV spectrum than in green, far infrared and near infrared, which is almost completely reflected by leaves. Thus an experimental study of using 12 W output 445 nm blue semiconductor laser for weed canopy cutting was carried out. The experiments were performed with direct laser radiation, the laser module was positioned using robotic manipulator with different speeds and cutting patterns.

Key words:

efficiency, laser, robot, weed

317-322 D. Kavaliauskaitė, J. Jankauskienė, E. Survilienė, O. Bundinienė,R. Starkutė, V. Zalatorius and R. Karklelienė
Competitive interaction between red beet and weeds, as affected by different weeding time
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Competitive interaction between red beet and weeds, as affected by different weeding time

D. Kavaliauskaitė, J. Jankauskienė, E. Survilienė, O. Bundinienė,R. Starkutė, V. Zalatorius and R. Karklelienė

Lithuanian Institute of Horticulture, Kauno str. 30, LT-543333, Babtai, Kaunas distr., Lithuania,telephone: +370-37-555-226, fax: +370-37-555-176, e-mail: d.kavaliauskaite@lsdi.lt

Abstract:

The competitive interactions between two red beet cultivars (‘Pablo F ’, prostrate,1and ‘Kamuoliai’, ect.) and weeds, affected at different weeding times, were studied for three years at the Lithuanian Institute of Horticulture. In all years, a long period of weeding gave lower crop biomass reduction of both cultivars. When weeding was delayed from 2 to 12 weeks after red beet germination the crop biomass of both cultivars was reduced by much more than half. From weed density studies, crop competition during long period of weeding reduced the number of germinating weed species and lowered seed germination of Chenopodium album L., Galinsoga parviflora Cav., Cappsella bursa-pastoris (L.) Medik., Stellaria media (L.) Vill. The two cultivars of red beet showed the same response to competition.

Key words:

competitive interaction, red beet, weed

465-470 L. Sarunaite, I. Deveikyte, R. Semaskiene and Z. Kadziuliene
The influence of grain legumes on spring wheat yield formation and phytosanitary state
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The influence of grain legumes on spring wheat yield formation and phytosanitary state

L. Sarunaite, I. Deveikyte, R. Semaskiene and Z. Kadziuliene

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

Abstract:

The aim of the present study was to determine the influence of grain legumes on spring wheat yield, its quality and phytosanitary state in an organic farming system. The experiment was carried out in 2007 and 2008 at the Lithuanian Institute of Agriculture in Dotnuva on a loamy Endocalcari-Ephypogleyic Cambisol. Grain legumes – pea, lupine, bean, vetch and wheat were sown as intercrops and sole crops, and were grown organically for grain. The productivity and phytosanitary state of spring wheat sole crops or intercrops depended on the species of grain legume, however, the results varied over the experimental years. In 2007, the vetch and wheat intercrop produced a significantly higher grain yield than wheat in sole crop or in other intercrops. In 2008, no advantages of legume and wheat intercrops were revealed. The nitrogen content was higher in wheat when it was grown with legumes.

Key words:

intercrops, leaf diseases, nitrogen content, weed

542-547 A. Velykis, S. Maiksteniene, A. Arlauskiene, I. Kristaponyte and A. Satkus
Mechanical weed control in organically grown spring oat and field pea crops
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Mechanical weed control in organically grown spring oat and field pea crops

A. Velykis, S. Maiksteniene, A. Arlauskiene, I. Kristaponyte and A. Satkus

Lithuanian Institute of Agriculture, Joniskelis Research Station,Joniskelis, LT–39301 Pasvalys District, Lithuania; e–mail: velykisalex@gmail.com

Abstract:

Experiments to study the effects of weed harrowing in an organic farming system were carried out during 2005–2007 at the Joniskelis Experimental Station of the Lithuanian Institute of Agriculture on a clay loam Gleyic Cambisol. Spring oat (Avena sativa L.) and field pea (Pisum sativum L.) crops were harrowed once and twice with a Regent spring-tine harrow at pre-emergence, early post-emergence and late post-emergence stages. This study indicates that at early growth stages of crops the uprooting effect of harrowing could be more important for weed control than at late stages. Early post-emergence harrowing (at 2–3 leaf stage) was the most effective for spring oat. Twice (pre-emergence and early post-emergence) harrowing of oat was not more effective than early post-emergence harrowing once, since early harrowing stimulates new sprouting of weeds. Pea crop damage by harrowing was less when the crop was harrowed at late post-emergence (beginning of stem elongation) stage. No difference of crop yield was determined among the treatments.

Key words:

clay loam, crop yield, field pea, harrowing, organic farming, spring oat, weed

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

Key words:

competition, critical period, red beet, weed, yield

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

Key words:

biodiversity, change of crops, weed