The effects of four different proportions of cow manure, 0, 20, 33 and 50% (V:V) and three Meloidogyne spp. inoculum levels (3,000; 6,000 and 9,000 J2 per plant) on the phenol concentration in the tomato roots, in the nematode female development, the giant cells induced by the nematode and on the reproduction of Pasteuria penetrans were investigated. The experiment was carried out in greenhouse, in a completely randomized design with twelve replicates, and evaluated 50 days after inoculation. The size of nematode females was higher when the plants were inoculated with 3,000 J2. Higher proportion of females infected by P. penetrans was observed when the plants were cultivated in the substrate without cow manure or when plants were inoculated with 3,000 J2. Plants inoculated with 9,000 J2 and cultivated on substrate with 20% of cow manure yielded more endospores. The phenolic content in the roots increased as higher proportions of cow manure were used in the substrate or when the plants were inoculated with the highest number of nematodes. The giant cells of plants cultivated on substrate with 33 and 50% of cow manure were less numerous, smaller and had less nuclei number, demonstrating the deleterious effect of organic amendments on the giant cells, on the nematodes and on the P. penetrans reproduction.
Pasteuria penetrans; root-knot nematode; biological control
