Effect Of Meloidogyne Javanica And Meloidogyne Incognita On Resistance Of Muskmelon Cultivars To Fusarium Wilt

Ihssan Naji and Walid Abu-Gharbieh
Plant Protection Department, University of Jordan, Amman, Jordan
E-mail: abugharb@ju.edu.jo

Abstract

A growth chamber experiment was conducted to study the interaction between M. javanica and/ orM. incognitaand the Fusarium wilt fungusF. oxysporumf. sp. melonis, using three muskmelon cultivars differing in their resistance to the fungus. Treatments included inoculation with the fungus alone 14 or 28 days after transplanting; root-knot nematodes alone inoculated singly or concomitantly at transplanting or 14 days after transplanting; and combinations comprising the nematodes and the wilt fungus. At termination all muskmelon cultivars with different degrees of resistance to Fusarium wilt, almost completely lost their resistance in presence ofM. javanica, but to a lesser extent by M. incognita. Wilting reached 100% in the resistant and moderately resistant cultivars inoculated with M. javanica 14 days earlier than the fungus alone. Also, M. javanica was more severe on plants than M. incognita. Considering all three cultivars, both root-knot nematode species exhibited early expression of plant wilting. It took 12.1, 14.8 and 12.4 days to show wilting in plants inoculated with M. javanica, M. incognita and both species, respectively, compared to 22.7 days in the Fusarium alone treatments. Furthermore, it took 9.0-13.3 days for expression of wilting when nematode preceded F. oxysporum f. sp. melonis inoculation by two weeks compared to 16.7-19.7 days when both disease causal agents were simultaneously inoculated 14 days after transplanting; indicating plant preconditioning by the nematode