Isolation and selection of active Bacillus strains that have the ability to control black-headed insect (Opisina arenosella Walker) causing damage to coconut trees in Ben Tre province

Abstract

Ben Tre province has the largest coconut growing area in the country, more than 79,000 hectares. However, this tree species is being damaged by the black-headed caterpillar (Opisina arenosella Walker), seriously affecting coconut tree productivity in Ben Tre province. In this study, from 32 soil samples collected in coconut garden areas and perennial uncultivated land in Ben Tre province, 96 Bacillus spp. strains were isolated and 30 biosurfactant strains were screened. Among them, the bacterial strain Bacillus amyloliquefaciens subsp. plantarum B9.10 and Bacillus velezensis D13 are capable of killing black-headed worms with an effectiveness of 100.00% and 86.67%, respectively, after 24 hours of monitoring. Analysis of surfactin content using ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) showed that both strains of Bacillus spp. all have the presence of the active ingredient surfactin, strain Bacillus amyloliquefaciens subsp. plantarum B9.10 reached a surfactin content of 0.60 mg/g and strain Bacillus velezensis D13 reached a surfactin content of 0.42 mg/g.