Paecilomyces formosus MD12, a Biocontrol Agent to Treat Meloidogyne incognita on Brinjal in Green House

Abstract

The present study was carried out to analyze the potential of fungi isolated from the rhizosphere of soybean, brinjal, tomato, and potato plants. The density of fungi varied in the pot soil and rhizosphere after Paecilomyces formosus MD12 treatment. The P. formosus MD12 population was 6.3 +/- 0.13 x 10(4) CFU g(-1) in the pot planted with brinjal, and the population increased in the rhizosphere (6.72 +/- 0.41 x 10(4) CFU g(-1)). P. formosus MD12 was cultured in the production medium, and the supernatant was used for egg inhibition studies on a root-knot nematode parasite, Meloidogyne incognita. It was revealed that maximum egg inhibition (94.7 +/- 6.2%) was obtained at 100% concentration of extract. The culture supernatant from P. formosus MD12 affected the development of M. incognita juvenile, and the mortality rate was maximum after 96 h (95 +/- 6%). Mortality was reduced when treated with 25%, 50%, and 75% supernatant. At 1 x 10(7) mL(-1) of spore suspension, we found reductions of 71.6 +/- 3.3% nematode populations in the soil, 60.7 +/- 2.2% from the root, and 63.6 +/- 2.4% egg mass compared with the control in the pot experiment. The culture supernatant applied at the 10% level showed a maximum mean reduction of the nematode population in roots (72.4 +/- 2.2%), soil (77.9 +/- 2.5%), and egg masses (73.2 +/- 1.5%), respectively. The presence of P. formosus MD12 in a soil environment could antagonize nematode parasites and improve soil amendment. The P. formosus MD12 strain showed good biocontrol ability against the root-knot nematode, M. incognita, under in vitro and green house experimental condition.