Nematicidal effect of chitosan on Meloidogyne incognita in vitro and on tomato in a pot experiment

The present study investigated to evaluate the potential of liquid chitosan of three concentrations (0.5, 1 and 2%) on Meloidogyne incognita (Kofoid and White, 1919) Chitwood, 1949 in vitro and on tomato under controlled conditions ((24 ± 1 °C, 60 ± 5% humidity). In vitro assay, the effect of the liquid chitosan concentrations on suppressing of hatching from eggs and second juvenile larvae (J2) mortality was determined. The reducing effect of the concentrations on the number of gall and egg mass on tomato roots and the J2 density in the soil was evaluated under controlled conditions. All concentrations suppressed hatch and increased J2 mortality more than control in vitro. The most effective concentration was found at 2% in vitro and its nematicidal effect on egg and J2 was over 70%. The results demonstrated that 0.5, 1 and 2% concentrations were significantly decreased gall/root, egg mass/root and J2 in soil compared to negative control under controlled conditions. No statistically significant difference was found between the nematicidal effects of the concentrations on the gall and egg mass (P≤0.05). It has been determined that 1 and 2% concentrations better suppress the J2 in soil than 0.5%. Although the nematicidal effect of 2% concentration was high in vitro and under controlled conditions, it was determined that it negatively affected plant biomass. Also, only 1% concentration of chitosan application controlled M. incognita on tomato by 58%. The present results show that the use of 1% liquid chitosan concentration against M. incognita will be more effective.