Abstract: To detect the efficacy of Bacillus thuringiensis NBIN863 against crop root-knot nematode disease in the field, the muskmelon plants with severe root-knot nematode disease in the greenhouse were irrigated, and the efficacy of NBIN863 against the nematode disease was investigated. The results showed that when the muskmelon was harvested 30 days later, in the group treated with NBIN863 agent, the proportion of dead plants was 40.00%, the average weight of obtained muskmelon was 2.41 kg, and the number of nematodes in muskmelon rhizosphere soil was about 22 heads per gram of rhizosphere soil. Compared with the control group treated with avermectin and water, the NBIN863 agent significantly reduced the root-knot nematode disease, improved the plant survival rate, and increased the muskmelon yield.

Key words: Bacillus thuringiensis, root-knot nematode disease, field efficacy, muskmelon