Infestations of root-knot nematodes, M eloidogyne species, associated with selected vegetable crops in Matara District in Sri Lanka.

Abstract

A survey on infestations o f root-knot nematodes, Meloidogyne spp. was conducted on seven vegetable crops, i.e., bitter-gourd, bottle-gourd, egg-plant, chili, okra, pumpkin and snake-gourd, at 13 localities representing vegetable growing regions in Matara District in Sri Lanka. At least 10 individual root systems o f each vegetable crop per locality were assessed at the mature stage for the percentage o f root system galled and a root-gall severity was determined. Meloidogyne species were identified based on the morphology o f perennial pattern o f mature females. Meloidogyne infestations were detected only on bitter-gourd, egg-plant, chili and okra. Three Meloidogyne species namely M. incognita, M. javanica and M. arenaria, were identified. However, species composition differed with respect to vegetable crops and locality. All the three Meloidogyne species were detected on okra at Denipitiya and Malimbada, and on bitter-gourd at Welipitiya as mixed populations. The frequency o f occurrence o f Meloidogyne species also varied among the vegetable crops tested. Overall, M. incognita was found to be the most prevalent species detected on all infested vegetable crops. The highest root gall severity was recorded on okra and egg-plant.