In vitro effect of Streptomyces purpeofuscus MTCC 6473 cell free filtrate and solvent extract on egg hatch and juvenile activity of Meloidogyne incognita

Streptomyces purpeofuscus MTCC 6473 was grown on five different culture media, namely nutrient broth, starch casein broth, oatmeal broth, Bennett’s broth and growth medium-93 for 4, 6, 8 and 10 days. Out of these, Growth Medium-93 consistently gave significantly higher biomass on all days of incubation, compared to other media. In vitro nematicidal test with CFF using J₂ and egg masses of root-knot nematode, Meloidogyne incognita showed an average immobility of 21.2 and mortality of 16.6 in J₂s with 2 day old culture that increased to 43.0 and 64.0, respectively, for 10 day old culture of S. purpeofuscus. A significant increase in % immobility and mortality was observed in 24 to 96 hrs exposure. All the seven dilutions of CFF inhibited hatching compared to control. The maximum % decrease in egg hatch (41.5), was in 80:1 dilution and least (2.7) in 1:1.25 dilution of CFF. The average % immobility (94.0) and mortality (92.0) in fraction of culture filtrate from the polar solvent (ethyl acetate) was significantly higher than immobility (82.5) and mortality (77.4) in the non-polar solvent (hexane) fraction.