EFFECT OF SPORE ATTACHMENT METHODS AND LEVELS ON INVASION AND PARASITISM OF ROOT-KNOT NEMATODE MELOIDOGYNE JAVANICA

Abstract

Spore attachment is the first stage in the life cycle of Pasteuria penetrans. Therefore, the present studies were planned to find out whether an attachment level which can provide better reduction in root-knot disease. There was a significant difference (P0.01) regarding numbers of eggmasses produced by females of Meloidogyne javanica in the treatments. Higher numbers of eggmasses (237) were recorded in the treatment where unencumbered J2s were inoculated after spinning followed by the treatment where J2s were inoculated without spores (225) but this difference was not significant. Both spore attachment techniques revealed their influence on eggmass production as fewer eggmasses were recorded in the treatment where encumbered J2s were inoculated compared to controls. Significantly lesser numbers of eggmasses (123) were recorded where J2s were encumbered by exposing them to a spore suspension in plastic trays than by the centrifuge treatment (173). Root galling differed significantly (P0.01) among treatments showing higher root galling in control treatment (5.2). Lesser root galling was observed where J2s were encumbered in the normal manner by exposing nematodes to spore suspension (3.6) while greater root galling (4.0) was observed in the treatment where J2s were encumbered after centrifugation. Similarly, there was a significant difference (P0.01) among females parasitized by P. penetrans showing a higher level of infectivity (13.8) in the treatment where J2s were encumbered by the normal attachment method as compared to the centrifugation method (11.6). There was no significant difference (P0.05) in fresh root weight of plants among treatments. There was no significant difference (P0.05) in number of eggs/eggmass produced by females of M. javanica between the treatments.