Identification of potential entomopathogenic bacteria in the culturable bacterial flora of the Brown Marmorated Stink Bug (Halyomorpha halys, Stål, 1885) (Hemiptera: Pentatomidae)

Abstract

The Brown Marmorated Stink Bug (Halyomorpha halys) has become a major invasive agricultural pest in Türkiye, particularly threatening hazelnut production in the Black Sea Region. This study aimed to isolate and identify culturable bacterial flora from H. halys populations in Türkiye and assess their potential as biological control agents. A total of nine bacterial isolates were obtained from diseased individuals and identified using morphological, biochemical, and 16 S rRNA gene sequencing analyses. A total of nine bacterial isolates were obtained and identified as belonging to six genera: Bacillus, Staphylococcus, Mammaliicoccus, Enterobacter, Acinetobacter, and Lysinibacillus. Insecticidal bioassays revealed that all isolates exhibited varying levels of pathogenicity against H. halys, with Bacillus thuringiensis (Hh18) causing 100% mortality in nymphs and 66% in adults at 1 × 10⁷ CFU/mL after 10 days. Staphylococcus aureus and Acinetobacter sp. caused 86% mortality in nymphs, while Mammaliicoccus sciuri achieved 53% mortality in adults. These quantitative results provide strong evidence for the entomopathogenic potential of native bacterial isolates against H. halys.