Ação de produto biológico na eclosão, mortalidade e na reprodução de Meloidogyne incognita no tomateiro

Abstract

Root-knot nematodes are one of the main pathogens that cause diseases in the tomato crop. Biological control with antagonistic agents has been investigated aiming to increase the nematoid control efficiency. Thus, the objective of this study was to evaluate different concentrations of the commercial product Nem-OutTM on hatching, mortality and reproduction of Meloidogyne incognita in tomato, under two forms of application this product. To evaluate the action of the product, dilutions were made in water to obtain the following concentrations: 1.25; 2.5; 5; 10; 20 and 40 g L-1. Eggs of M. incognita were placed in hatch chamber containing solutions of the different concentrations and kept in room at room temperature. The number of juveniles of the second stage (J2) of M. incognita hatched was done 48 hours and the others readings every 24 hours for 14 days. Eggs kept in water were considered as controls. To assess mortality, J2 of M. incognita were exposed at the same concentrations for 24 hours. After this period, the solutions were eliminated and counted the number of J2 mobile and immobile. The J2 that remained immobile after 12 hours in water were considered dead. In the study of the action of the biological product in the population reduction of M. incognita in tomato used the mentioned concentrations and two forms of application (via irrigation and pit). In tomato seedlings were inoculated 3,692 eggs of M. incognita. Infectivity and reproduction evaluations were done thirty days after inoculation. There was a significant reduction in the hatching of J2 of M. incognita at concentrations of 20 and 40 g L-1. Observed a significant reduction in the hatching of J2 of M. inocgnita at the concentrations of 20 and 40 g L-1. From the concentration of 5 g L-1 there was less motility and higher J2 mortality, causing a 92% mortality at this concentration. The infectivity and reproduction of M. incognita were significantly influenced by the effect of the interaction between concentrations and the application of the product. In the surface application, the increase of the concentrations of the Nem-Out™ resulted in linear growth of the FR, whereas in the application through the pit there was a quadratic effect with the increase of the concentrations. Concentrations of 1.25 and 2.5 g L-1 applied via the surface provided lower number of eggs per gram of root. The application of the biological product on the surface provided a larger mass of the root system, regardless of the concentration. The biological product has nematicidal action and the promotion of root system growth.