Potential of bacteria isolated from chitin-enriched soil against Euschistus heros (Hemiptera: Pentatomidae)

Biological control using entomopathogenic microorganisms is a more sustainable alternative to chemical pesticides for managing insect pests in agriculture. The isolation of novel entomopathogenic microorganisms is essential to broaden the genetic base of bioinsecticides, which will enable their effective application under diverse cropping conditions. This study aimed to isolate entomopathogenic bacteria from chitin-enriched soil with potential activity against E. heros.

From soil amended with chitin for 90 days, isolates CC1, CC2, and CC3 were obtained and identified as Bacillus thuringiensis, Bacillus altitudinis, and Priestia megaterium, respectively. Bioassays for control of E. heros indicated that the tarsal contact inoculation method was the most effective compared with dorsal contact and ingestion methods, with the tested isolates. Insect mortality increased with higher concentrations of inoculated bacteria. Isolates CC1 and CC2, using the tarsal inoculation method at the highest cell concentration (2.5 × 10⁹ CFU mL^-1), caused stink bug mortalities of 79% and 61% within 10 days, respectively. Isolate CC3 showed the lowest insecticidal activity.

The bacteria CC1 (B. thuringiensis) and CC2 (B. altitudinis), isolated from chitin-enriched soil, demonstrate promising potential as bioinsecticides against E. heros under laboratory conditions. To our knowledge, these findings represent the first report of the use of B. altitudinis in the control of E. heros. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.