SUSCETIBILIDADE DE MILHO, SOJA E CAPIM AMARGOSO AO NEMATOIDE DAS LESÕES RADICULARES

RESUMO - Plantas daninhas sao fatores limitantes a produtividade de soja e milho pela matointerferencia, principalmente o capim amargoso ( Digitaria insularis ), cuja ocorrencia aumenta anualmente devido a resistencia ao herbicida glyphosate. Alem da competicao direta com a planta cultivada, a planta daninha pode atuar como hospedeiro alternativo de nematoides. Assim, foi avaliada a suscetibilidade do capim amargoso ao nematoide Pratylenchus brachyurus em relacao a plantas de milho e soja. O experimento foi conduzido em casa de vegetacao, comparando a reproducao do nematoide no capim amargoso, quatro genotipos de milho (DKB 285 VT PRO 2, AS 1555 PRO 2, P 30F53 YHR e DKB 330 VT PRO 2) e uma cultivar de soja (NA 5909 RR). Observou-se que a reproducao de P. brachyurus no capim amargoso foi tao eficiente quanto aquela observada nos genotipos de milho e soja. Alem disto, o capim amargoso pode ser considerado uma planta suscetivel ao nematoide por apresentar fator de reproducao igual a 4,2 e nao diferir das demais especies estudadas. Palavras chave: Pratylenchus brachyurus , Digitaria insularis , Zea mays , Glycine max , hospedeiro. SUSCEPTIBILITY OF MAIZE, SOYBEAN AND SOURGRASS TO ROOT LESION NEMATODE ABSTRACT - Weeds are limiting factors to productivity of soybean and maize, due to weeds interference especially by sourgrass ( Digitaria insularis ), whose occurrence has increased annually due to the resistance to glyphosate herbicide. Besides the direct competition with the crop, weed can also act as an alternative nematode host. This study aimed to evaluate the susceptibility of sourgrass to the Pratylenchus brachyurus in relation to maize and soybean plants. The experiment was conducted in a greenhouse, comparing the nematode reproduction in the sourgrass and four maize genotypes DKB 285 VT PRO 2, AS 1555 PRO 2, P 30F53 YHR and DKB 330 VT PRO 2) and one of soybean (NA 5909 RR). The reproduction of P. brachyurus was as efficient in the sourgrass as in maize and soybean. In addition, sourgrass can be considered susceptible to the nematode since the reproductive factor was 4.2, similarly to the other species studied. Keywords: Pratylenchus brachyurus, Digitaria insularis , Zea mays , Glycine max , host.