In 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).
Glycine max; soybean; root-knot nematode; population density; soil suppressiveness; biocontrol
