Determination of fungal pathogens affecting the rearing of Calosoma sycophanta l. (Coleoptera: carabidae)

Calosoma sycophanta L. (Coleoptera, Carabidae) is reared in many laboratories for biological control with Thaumetopoea pityocampa (Den. & Schiff.) known as pest of pine species. However, the production number of C. sycophanta is in a significant decline because of the increasing insect deaths in rearing laboratories. The main factor of the decrease is diseases caused by entomopathogenic organisms. In this study, fungal pathogens in C. sycophanta taken from rearing laboratories were studied between the years 2016-2021. 3 different fungus isolations were detected. The fungi were examined morphologically, and their spores were measured. Sequence analyzes of ITS regions were examined and their similarities with other fungus species were investigated. Thus, it was determined that the fungus species were Beauveria bassiana, Fusarium proliferatum and Metarhizium brunneum. These fungus species were tested to determine the pathogenicity of C. sycophanta on larvae and adults. It was determined that B. bassiana showed the highest mortality rate of 55% in larvae, F. proliferatum showed up to 100% mortality in larvae in the last instar stage, and M. brunneum decreased efficiency of ovulation by 59%. At the same time, it was determined that mortality rate of B. bassiana by direct contact was higher (58%) than by contamination of food (16%). The results of the study show that rearing laboratories are at risk for fungal diseases. In the study, entomopathogenic fungus in C. sycophanta were diagnosed at species level and their pathogenicity was investigated for the first time.