Evaluation of organic oils for the management of root-knot nematode, Meloidogyne incognita and fungus infesting cucumber under polyhouse conditions

Root-knot nematode, Meloidogyne incognita and Fusarium oxysporum f. sp. cucumerinum disease complex is one of the major challenges that cucumber cultivators face in protected cultivation. A polyhouse study was conducted to determine the comparative efficacy of organic oils of neem, mustard and jatropha @ 10 and 20% v/w, as seed treatment against root-knot nematode, Meloidogyne incognita and F. oxysporum f. sp. cucumerinum disease complex on cucumber. Chemical checks with carbosulfan, 25 EC @ 3% a.i v/w, as well as untreated checks were also maintained. Three main treatments, viz., nematode alone, fungus alone and nematode and fungus inoculated simultaneously, were taken. The data showed that shoot length in all the treatments was significantly better over untreated inoculated checks viz., nematode alone (80.3 cm), fungus alone (85.1 cm) and nematode + fungus simultaneously (85.0 cm). Among the various treatments, maximum shoot length was observed in seed treatment with neem oil @ 20% v/w (144.3 cm), followed by mustard oil @ 20% v/w (141.4 cm), irrespective of whether the nematode or fungus was inoculated individually or concomitantly. In case of plants inoculated with nematode alone, number of galls per plant was minimum in case of neem oil (177), followed by mustard oil (186), as compared to untreated inoculated check (324). In plants inoculated with nematode and fungus concomitantly, number of galls per plant was the least in case of neem oil (167), followed by mustard oil (175), as compared to untreated inoculated check (319).