Effectiveness of local entomopathogenic fungal isolates against eggs of Capnodis tenebrionis Linnaeus (Coleoptera: Buprestidae)

Abstract Background The peach flat-headed rootborer, Capnodis tenebrionis Linnaeus (Coleoptera: Buprestidae), is an important pest of stone fruit. The adult females lay eggs on the stem near the root collar of the plant or 2 cm deep in the soil. The egg stage lasts approximately 8–12 days. The larvae hatch from the egg, quickly penetrate the plant tissue, and damage the roots. The adults damage the upper parts of the plant. Entomopathogenic fungi (EPF) are among the biological control agents used in pest control methods in recent years. The egg stage of C. tenebrionis is the most exposed stage to local EPF isolates as it occurs mainly in the soil. In this study, the efficacy of eight local EPF isolates, Metarhizium anisopliae (C7, C5, No. 1, and C2), Trichoderma harzianum (C11), Beauveria bassiana (C8), and Clonostachys rosea (C10), was tested against the egg stage of C. tenebrionis . The study was conducted in Malatya (Türkiye) in 2022. Results Metarhizium anisopliae (C7) had the highest efficacy, achieving C. tenebrionis egg mortality rate of 89.5%. Other effective strains included M. anisopliae (C5) (78.95%) and M. anisopliae (No. 1) (73.68%). Lower, yet notable, effects were found in M. anisopliae (C2) and T. harzianum (C11) with mortality rates of 57.89 and 47.37%, respectively. Less effective isolates, such as B. bassiana (C8) and C. rosea (C10), showed minimal mortality rates, indicating a lesser potential for pest control. Conclusions The findings suggest that the isolates of M. anisopliae have ovicidal activity against C. tenebrionis and are promising for the control of the pest. This practice can be integrated into sustainable pest control methods after being supported by field studies.