Virulence and transmission potential of indigenous entomopathogenic fungi against Halyomorpha halys (Stål) (Hemiptera: Pentatomidae)

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Bayramoğlu Z., Doğancı M. A., Öktem B., Çolak H., Eski A., Biryol S., ...Daha Fazla

BIOCONTROL JOURNAL OF THE INTERNATIONAL ORGANISATION FOR BIOLOGICAL CONTROL, cilt.71, sa.4, ss.1-14, 2026 (SCI-Expanded, Scopus)

Özet

The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a highly invasive pest causing severe economic losses in Türkiye, especially in hazelnut-producing regions. This study presents laboratory evaluations of indigenous entomopathogenic fungi against H. halys, emphasizing mortality patterns, indirect infection, and horizontal transmission. All selected isolates caused concentration-dependent reductions in survival and increases in mortality. Of 20 local fungal isolates tested, four—Beauveria bassiana KTU-24 and Pa4, Metarhizium brunneum Gg-12, and Metarhizium flavoviride As-18—consistently showed the highest virulence against both nymphs and adults. B. bassiana KTU-24 was the most effective, exhibiting the lowest median lethal concentration (LC50) for both nymphal and adult stages. Contact with fungus-contaminated surfaces and food resulted in high infection levels, reaching over 90% mortality in adults and up to 80% in nymphs, demonstrating that conidia remained infective in the environment without direct application. Horizontal transmission assays further showed that fungal infections spread efficiently from treated to untreated individuals. This horizontal transmission was more pronounced in adults and was strongest for the KTU-24 isolate. Overall, the findings show that indigenous entomopathogenic fungi, particularly B. bassiana KTU-24 and M. flavoviride As-18, exhibited high virulence with effective indirect infection and significant horizontal transmission capacity. These characteristics indicate substantial potential for initiating epizootics in aggregated H. halys populations and support further development of locally adapted fungal isolates as sustainable microbial control agents within integrated pest management programs.