Efficacy of Bacillus thuringiensis integrated with other non-chemical materials to control Meloidogyne incognita in tomato

Abstract

The effects of Bacillus thuringiensis (Bt, Dipel 2X, at 12 mg/kg soil), grape marc (GM), chicken litter (CL), both at 10 g/kg soil, and the neem-based product Achook® (AC), at 500 mg/kg soil, alone or as combinations of Bt with each of the other three products, on Meloidogyne incognita infecting tomato were assessed in a glass-house pot experiment. Controls consisted of non-inoculated pots, untreated pots inoculated with M. incognita, and pots treated with oxamyl at 10 mg a.i./kg soil. All treatments significantly improved plant growth and suppressed the nematode compared to untreated inoculated plants. Among the organic materials, CL and GM were the most effective with root gall reductions of 75.5% and 72.2%, respectively, similar to oxamyl (79.0%). The efficacy of B. thuringiensis against M. incognita was significantly increased by addition of the organic amendments to the soil. The best combination with which to reduce root galling (by 86.2%) and second-stage juveniles in the soil (by 80.5%) was Dipel 2X + CL, followed by Dipel 2X + GM and Dipel 2X + AC. These combined treatments also improved plant growth parameters. Therefore, B. thuringiensis (Dipel 2X) applied to soils in combination with organic amendment materials may be considered as a promising alternative to chemicals for controlling M. incognita.