Effect of Entomopathogenic Fungi, (Cordycipitaceae), on the Bark Beetle, (L.), under Field Conditions.

The spruce bark beetle, (L.), attack progression (adult and larval galleries) and parental and offspring mortality rate were assessed in managed forests of the Poiana Ruscă and Bihor Mountains, along with Western Romanian Carpathians using fungal () treatments. The results show that the effect of on adult (maternal) gallery length was similar to the untreated variant and was less effective than the synthetic insecticide lambda-cyhalothrin applied at a dose of 50 g/L. Additionally, its effect on the mean larval gallery number per maternal gallery was low. did not have a significant influence on the attack progression. Significant correlations between log diameter and attack progression were detected; such differences were higher than the effect of any treatment. Altogether, abiotic (low humidity, high temperature) and biotic factors (log diameter) influenced the bark beetles' attack progression and reduced the entomopathogenic fungal effects. Considering the efficacy of the treatment on logs infested with , the results showed that parents and offspring were infected, but even if the fungal treatment was applied in high concentrations, the mortality rate remained relatively low. Further research is necessary to test if different strains and their commercially recommended concentrations might be more effective under dry and warm climate conditions, respectively.