Suppression of Meloidogyne incognita race 2 with some entomopathogenic agents

Root-knot nematode Meloidogyne incognita (Kofoid & White) Chitwood is one of the most important species causing yield and quality reduction in crops worldwide. Because they are of soil origin, the control of this nematode is very difficult and uneconomical. Due to environmental problems caused by intensive pesticides used to control plant diseases and pests, research on alternative control methods has increased. One of the most valuable alternative control methods is biological control. This work was conducted to determine the larvicidal effects of isolates of fungi and bacterial species, whose bio-insecticidal effects are known and widely studied, against second-stage juveniles (J2) of root-knot nematode M. incognita race 2. In the experiments, fungal isolates of Beauveria bassiana (ET 10, ET 101) and Aspergillus flavus (ET 95, ET 102) and bacterial strains of Brevibacillus brevis (FD-1), Bacillus thuringiensis subsp. kenyae (FDP-8, FDP-42), Bacillus atrophaeus (FD-17) and Bacillus cereus (FD-63) species were used. Fungal isolates were applied in stock suspension (1X), diluted with sterile distilled water to 5X and 10X doses, and bacterial strains were applied at 1 × 106, 1 × 107, and 1 × 108 cfu mL–1 concentrations. In vitro experiments were set up with 3 replications, sterile distilled water was used in the negative control and a commercial nematicide (Velum Prime ®️ SC 400, Bayer) was used in the positive control. At the end of the 1st, 3rd, and 7th days, the results of the applications were counted and evaluated according to the percent mortality rates. When the percent mortality rates obtained at the end of the 7th day were compared with the negative control, the most effective results were obtained from the 5X dose of ET 102 in fungal isolates (39.88%) and the 1 × 108 cfu mL–1 concentration of FD-63 in bacterial strains (65.07%). It is thought that the ET 102 fungal isolate and FD-63 bacterial strain used in this study have the potential to be biological control agents against M. incognita race 2 juvenile. It was concluded that these isolates can be included in integrated pest management strategies against root-knot nematodes by making field trials.