Oil cakes soil amendment effects on Meloidogyne incognita, root-knot nematode infecting tomato

In a pot experiment, oil cakes of cotton, flax, olive, sesame and soybean were mixed with soil at the rate of 5, 10, 15, 20 or 50 g/kg soil. We compared their nematicidal potential with carbofuran as a standard against the root-knot nematode, Meloidogyne incognita infecting tomato. Their effects on the growth parameters of tomato plants were also investigated. The results showed that M. incognita populations in the soil and root galling were significantly suppressed when the tested cakes, at all rates, were allowed to decompose in the soil. All oil cakes exhibited varying degrees of reduction compared to the control. The highest reduction in galls was noted in plants treated with sesame cake, whereas the lowest reduction was observed in plants treated with olive cake. On the other hand, the highest reduction in J2 was noticeable in the plants grown in olive-cake-amended soil followed by sesame, soybean, cotton and flax cake. In addition, employing a high rate of the tested cakes gave higher activity in suppressing the nematode both in the soil and in tomato roots than using low rate. The data also indicated that all cakes, at low rates, significantly increased growth indices of tomato over control treatment, except cotton cake which decreased it, particularly in the root system. Phytotoxicity was associated with the higher rates of oil cakes tested except sesame cake. These oil cake soil amendments could prove to be one component in integrated root-knot nematode management for tomato in conventional and organic production systems. © 2009 Taylor & Francis.