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

## TL;DR

Researchers found bacteria in chitin-rich soil that can kill Euschistus heros insects, offering a sustainable alternative to pesticides.

## Contribution

This is the first report of using Bacillus altitudinis to control Euschistus heros.

## Key findings

- Bacillus thuringiensis and Bacillus altitudinis isolates caused up to 79% mortality in E. heros under lab conditions.
- Tarsal contact inoculation was more effective than other methods for delivering the bacteria.
- Priestia megaterium showed the lowest insecticidal activity among the tested isolates.

## Abstract

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.

B. thuringiensis and B. altitudinis, isolated from chitin‐enriched soil, causing mortality in Euchistus heros under laboratory conditions. First report of B. altitudinis in the control of E. heros.