Selection of Bacillus thuringiensis against Pathogenic Nematodes Attacking Pepper Tree

Abstract

Nine strains belonging to the Bacillus genus have been isolated from soil samples in Tien Phuoc district, Quang Nam province. They were capable of surviving at 42°C, and the Bl, B4, B7 and B9 strains could produce toxic crystals at this temperature. B7 had the most promising characteristics in terms of spore-forming ability. The result of the 16S rRNA gene sequencing showed that B7 belongs to the Bacillus thuringiensis species, which is known to effectively control root-knot Meloidogyne sp. nematodes attacking pepper tree. This study was aimed at evaluating the inhibitory effect of the bacterial isolate under study on root-knot eggs and juveniles. It was shown that the highest inhibitory activity of the cultures of the bacterial strains under study was observed at their concentration of 109cells/mL; in this case, up to 89.67% of nematode eggs and 100% of juveniles J2 were killed after 10 h of treatment. Bacillus thuringiensis, Meloidogyne sp., pepper tree, root-knot, nematodes We are grateful to the Danang University of Science and Education and Duy Tan University for supporting this study.