Planta Daninha (Jan 2010)
Eficácia de herbicidas inibidores da ACCase no controle de gramíneas em lavouras de soja Efficacy of ACCase-inhibiting herbicides in controlling grass weeds in soybean crops
Abstract
Objetivou-se com este trabalho avaliar a eficácia de herbicidas inibidores da ACCase, aplicados isoladamente ou em associações, no controle das espécies de plantas daninhas pertencentes à família das gramíneas Brachiaria decumbens, Digitaria ciliaris, Eleusine indica, Brachiaria plantaginea e Cenchrus echinatus, na cultura da soja. O experimento foi conduzido em campo, em delineamento de blocos ao acaso com quatro repetições. Os tratamentos avaliados foram: clethodim (84 g ha-1), clethodim + quizalofop-p-ethyl (48 + 40 g ha-1), [clethodim + fenoxaprop-p-ethyl] (50 + 50 g ha-1), sethoxydim (230 g ha-1), tepraloxydim (100 g ha-1), fluazifop-p-butyl (125 g ha-1), haloxyfop-methyl (60 g ha-1) e testemunha sem herbicida. A convivência das plantas de soja com as gramíneas infestantes resultou em perda significativa na produtividade de grãos. Os melhores níveis de controle de B. decumbens foram verificados com a utilização de haloxyfop-methyl. Tepraloxydim pode ser considerado seletivo a B. decumbens. Nenhum tratamento proporcionou controle final de D. ciliaris superior a 90%, porém menor eficiência foi verificada quando se aplicaram sethoxydim e fluazifop-p-butyl. Apenas os tratamentos sethoxydim e [clethodim + fenoxaprop-p-ethyl] não mostraram controle satisfatório de E. indica. B. plantaginea foi a espécie mais facilmente controlada pelos herbicidas avaliados; no entanto, haloxyfop-methyl, tepraloxydim, clethodim e [clethodim + fenoxaprop-p-ethyl] se destacaram no controle dessa invasora. A adição de quizalofop-p-ethyl ao clethodim proporcionou incremento significativo no controle de C. echinatus. Também os herbicidas haloxyfop-methyl e tepraloxydim apresentaram controle satisfatório dessa espécie daninha.The objective of this work was to evaluate the efficacy of ACCase-inhibitors (ariloxyfenoxypropionates and cyclohexanodiones), applied alone or in combination, in controlling the grass weed species Brachiaria decumbens, Digitaria ciliaris, Eleusine indica, Brachiaria plantaginea and Cenchrus echinatus in soybean crop. The study was carried out in the field in a randomized block design with four replicates. The following treatments were evaluated: clethodim (84 g ha-1 ), clethodim + quizalofop-p-ethyl (48 + 40 g ha-1), [clethodim + fenoxaprop-p-ethyl] (50 + 50 g ha-1), sethoxydim (230 g ha-1 ), tepraloxydim (100 g ha-1 ), fluazifop-p-butyl (125 g ha-1 ), haloxyfop-methyl (60 g ha-1 ) and control (no herbicide). In the presence of the infesting weeds, soybean grain yield was significantly reduced. The highest efficiency of B. decumbens control was observed with the application of haloxyfop-methyl. Tepraloxydim was quite selective to B. decumbens. No treatment promoted a final control of D. ciliaris higher than 90%; nevertheless, the lowest efficiencies were verified with the application of sethoxydim and fluazifop-p-butyl. The only treatments that did not present a satisfactory control of E. indica were sethoxydim and [clethodim + fenoxaprop-p-ethyl]. The species most easily controlled by the herbicides evaluated was B. plantaginea. However, haloxyfop-methyl, tepraloxydim, clethodim and [clethodim + fenoxaprop-p-ethyl] presented the highest efficiency rates for controlling this weed. The addition of quizalofop-p-ethyl to clethodim significantly increased C. echinatus control The herbicides haloxyfop-methyl and tepraloxydim also presented a satisfactory control of this grass weed.
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