Pathogenicity of Fusarium oxysporum and Meloidogyne incognita and cumulative effects on Tomato

The pathogenicity of wilt fungus Fusarium oxysporum f. sp. lycopersici and root-knot nematode Meloidogyne incognita was evaluated at different inoculum levels ontomato Solanum lycopersicum. Results showed that with the increase in time interval as well as inoculum level, there was corresponding increase in wilt indices. At the highest inoculum (4 g) mycelial mat! pot after 15 days of inoculation, there was complete wilting of all the lower leaves and terminal portion of stem. In general, lethal effects on tomato plant were observed at 2 g mycelial mat (containing 3 x 10⁶/conidia) pot/500g soil, wherein slight drooping of lower leaves was recorded after 30 days of inoculation. Pathogenicity of M incognita was also tested on tomato. An initial inoculum level of 1,000 J₂/500g soil caused significant reduction in plant growth characters and 2 J₂/g soil was found to be threshold level. Both the pathogens simultaneously or 10 days prior the other one revealed early expression of wilt symptoms in the treatments where fungus and nematode were inoculated simultaneously (N+F) or nematode was inoculated 10 days prior to fungus (N+F₁₀).