Pesquisa Agropecuária Brasileira (Nov 1999)
CONTROLE DE MELOIDOGYNE JAVANICA COM PASTEURIA PENETRANS CONTROL OF MELOIDOGYNE JAVANICA BY PASTEURIA PENETRANS
Abstract
Objetivou-se, com esse trabalho, avaliar a eficiência de Pasteuria penetrans no controle de Meloidogyne javanica em condições de casa de vegetação. Os tratamentos eram compostos de quatro níveis de inóculo de P. penetrans, 0, 10x10(5), 50x10(5) e 100x10(5) endósporos/kg de solo autoclavado. Imediatamente após a inoculação da bactéria P. penetrans no solo autoclavado, 1.000 juvenis de segundo estádio de M. javanica foram inoculados em cada vaso. Quarenta e oito horas após a inoculação do nematóide, uma plântula de soja cv. FT-Cristalina, com três dias de idade, foi transplantada para cada vaso. O experimento foi avaliado em duas etapas: a primeira, 89 dias após o transplantio da soja, e a segunda, 90 dias após um segundo()plantio de soja, em seqüência a um pousio de 30 dias. Na primeira avaliação, o maior peso da matéria fresca da planta foi obtido no tratamento com 100x10(5) endósporos/kg de solo, o que diferiu significativamente (PIn a greenhouse experiment, the efficiency of Pasteuria penetrans against Meloidogyne javanica was evaluated on soybean cv. FT-Cristalina using four inoculum levels of P. penetrans viz: 0, 10x10(5), 50x10(5) and 100x10(5) endospores/kg of soil. Immediately after inoculating the autoclaved soil with P. penetrans, 1,000 second-stage juveniles were inoculated in each pot. After 48 hours of nematode inoculation, a 3-day old soybean seedling was transplanted in each pot. The experiment was evaluated in two steps of which the first evaluation was made after 89 days of transplanting the seedlings; and the second after 90 days of soybean sowing in sequence with a following period of 30 days. In the first evaluation, the highest fresh plant weight was observed in treatment with 100x10(5) endospores/kg of soil which differed significantly (P<0.05) from other treatments except the untreated control. The maximum increase in fresh pod weight of treatment with 100x10(5) endospores/kg of soil differed significantly (P<0.05) from the other treatments. The final nematode density in soil and roots for treatments 10x10(5), 50x10(5) and 100x10(5) endospores/kg of soil was significantly (P<0.05) lower than the untreated control. The nematode control obtained for treatments with 10x10(5), 50x10(5) and 100x10(5) endospores/kg of soil was 50.9%, 89.1% and 81.8% respectively. In the second evaluation, the control obtained for treatments 10x10(5), 50x10(5) and 100x10(5) endospores/kg of soil was 94.7%, 99.7% and 100%, respectively, in comparison to the untreated control. P. penetrans was highly efficient in the control of M. javanica even at the lowest concentration (10x10(5) endospores/kg of soil).
Keywords
