INFLUENCE OF FUSARIUM-OXYSPORUM, A MUTUALISTIC FUNGAL ENDOPHYTE, ON MELOIDOGYNE-INCOGNITA INFECTION OF TOMATO

Tomato plants were inoculated with a non-pathogenic Fusarium oxysporum strain (Sacc.) Snyd. & Hans. and 3 weeks later with Meloidogyne incog nita Kofoid & White second-stage juveniles. M. incognita reproduction in F. oxysporum-colonized tomato plants was reduced 50% over F. oxyspo rum-free plants. Plant growth was not affected except at high nematode densities, where root weight, but not root length, decreased in F. ox ysporum-colonizes plants. Presumably, this was due to increased number s and sizes of nematode-induced galls in F. oxysporum-free roots. The non-pathogenic isolate of F. oxysporum was frequently reisolated from cortical tissue of surface-sterilized tomato roots. Fungal colonizatio n of young root tissue was also confirmed.