EVALUATION OF EFFICACY OF PASTEURIA PENETRANS ALONE AND IN COMBINATION WITH VERTICILLIUM CHLAMYDOSPORIUM AGAINST MELOIDOGYNE JAVANICA

Abstract

The potential control of Meloidogyne javanica using Pasteuria penetrans (Pp) alone and in combination with Verticillium chlamydosporium (Vc) was tested in earthen pots following a cropping sequence "tomato-tomato-tomato” over three crop cycles. After the final harvesting, analysis of variance showed significant effect of treatments (P<0.01) regarding number of eggmasses, galls and nematode female populations. Similarly, significant effect of treatments (P<0.01) was also recorded in case of infected nematode females with Pasteuria and number of eggs/eggmass while no significant effect (P >0.0 5) was observed in case of endospore production. Higher numbers of eggmasses (360) and root galling (6.2) was observed where biocontrol agents were absent (control). The treatments showed 46.58, 58.85 and 33.13 percent reduction in number of galls, eggmasses and nematodes in Pp alone and 43.34, 55.21 and 30.09 percent reductions in Vc+Pp treatments respectively. Numbers of females infected with the endospores of P. penetrans were recorded higher in Pp-3 alone treatment (13.2) followed by Vc+Pp combined treatment (13.0) and maize rotated treatment (10.4) respectively. Significantly lesser number of eggmasses, galls and nematodes were recorded in pots where tomato was rotated with maize (treatment 3) compared with control. Thus rotation prevented the buildup of nematode population and resulted in a 72% decrease in numbers of eggmasses, 38% in root galling and 46% regarding female populations over the control after the final harvest. Maximum colony forming units of V. chlamydosporium per gram of soil were recorded after its addition to the soil. The fungus established in the soil during the first crop and soil colonization of the fungus was also observed after final crop.