Tag Archives: weed emergence

1119-1127 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
Abstract |
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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.

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169-174 O. Auškalnienė, A. Kadžys, A. Auškalnis and G. Pšibišauskienė
Weed emergence and survival in spring barley
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Weed emergence and survival in spring barley

O. Auškalnienė, A. Kadžys, A. Auškalnis and G. Pšibišauskienė

Lithuanian Institute of Agriculture
Instituto Alėja 1, LT – 58344, Akademija, Kėdainiai distr.;
e-mail:algis@lzi.lt

Abstract:

Weed emergence and survival in spring barley was investigated in field trials at the Lithuanian Institute of Agriculture in 2003–2005 and 2008.The soil of the experimental site – Endocalcary-Endohypogleyic Cambisol, loam.Conventional soil tillage moldboard ploughing in the autumn and pre-sowing soil tillage in spring – was used. Spring barley var ‘Luokė’ during 2003–2005 and ‘Aura DS’ in 2008 was sown in the second half of April, at a rate of 4.0 million seed ha-1. Weed emergence was observed in nine unsprayed plots of barley, in 4 places per plot (total 36 places), sites of 50 x 50 cm in size were marked, where all weeds present were counted weekly from sowing until the end of heading.There were found 11–20 weed species in the spring barley stands. In an extremely dryspring the weed species number was lowest. 36% of all the weeds that emerged in the spring barley growing period emerged during the first assesment performed at the second decade of May.Weed survival depends on the general weed number in the field and cropdevelopment. When weediness was quite low, later emerged weeds were not able to compete with barley and earlier-emerged weeds.

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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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