Evaluation of Pochonia chlamydosporia (Goddard) Isolates for Suppression of Meloidogyne incognita, Root-Knot Nematode of Tomato

Abstract

Restricted applications of chemical nematicides has directed to the development of ecofriendly alternatives. Culture filtrates in different concentrations (20, 40, 60, 80 and 100%) of the six isolates of Pochonia chlamydosporia were evaluated for their nematicidal activity. Significant variations were observed in the inhibitory activity of culture filtrates against egg hatching and second stage juveniles of M. incognita at different concentrations. The culture extract of PC-6 showed maximum inhibition of egg hatching followed by PC-1. On the other hand PC1 isolate caused high mortality of second stage juveniles followed by PC-6. Significant variation among the isolates was observed for parasitism of M. incognita juveniles and eggs. Among the tested isolates, PC-1 and PC-6 were selected for the further studies based on in vitro egg inhibition and larval mortality. Both PC1 and PC6 applied at the rate of 6 × 103 chlamydospores per gram of soil per plant reduced the population of nematode and improved the growth and productivity of plant under screen house and field conditions. Different growth parameters like plant height, fresh shoot weight, dry shoot weight, fresh root weight and dry root weight were measured. Efficacy of isolates was different in winter and summer crop. No significant difference among the treatments was observed in summer crop. However in winter crop, considerable effect of both isolates was observed. Fungal application was effective at the rate of 6 × 103 chlamydospores per gram of soil per plant in both winter and summer crops. Root coating with chlamydospores suspension significantly reduced number of galls on roots. Little effect of both isolates was observed with mycelial root coating. No lesions were seen on P. chlamydosporia inoculated roots of tomato plants.