Effect of Bacillus subtilis and chitosan in Biological Control of Root-knot Nematode, Meloidogyne incognita on Tomato

The root–knot nematode (Meloidogyne incognita) on tomato (Solanum lycopersicum Linn.) is one of the most important plant pathogens, causing economic damage worldwide and in Iran. In order to biologically control this nematode, after nematode multiplication on the susceptible tomato variety (Early Orbana Y) and obtaining a pure and abundant nematode population, the plants were irrigated with a solution of 3 per thousand Probi 96 (containing Bacillus subtilis) and Chitoplus (containing chitosan). After 45 days of applying the treatments, the seedlings were transferred from the greenhouse to the laboratory, and growth indices such as fresh and dry shoot weight, shoot length, fresh and dry root weight, root length. Also, disease indices such as the average number of galls, the number of nematode egg masses in the root, the number of nematode eggs in the root, the number of second–stage juveniles in the soil, and the gall index were measured. The results showed that the use of B. subtilis and chitosan, either alone or in combination, led to an increase in plant growth indices and a reduction in nematode pathogenicity indices. Therefore, based on the results obtained in this study, it can be concluded that the use of these compounds is suggested as one of the effective strategies in an integrated management program for root–knot nematodes in tomatoes.