The efficacy of some entomopathogenic fungi against the poultry red mite, Dermanyssus gallinae

The poultry red mite, Dermanyssus gallinae, is a widespread, ectoparasitic pest of poultry, including vectoring diseases. Its control is reliant on synthetic acaricides but they cause substantial harm to humans and ecosystems. Alternative control methods, especially the use of entomopathogenic fungi, are currently a special focus. In this laboratory study, the efficacy of three Beauveria bassiana isolates and one Isaria fumosorosea isolate, obtained from soil in Tbilisi, Georgia, was investigated. The experiment was conducted in a completely randomized design with five replicates and five mites per replicate. The fungal isolates were applied as suspension sprays at 1x108 spores/mL to adult mites in Petri dishes. Counts of dead mites were conducted daily from days 3 to 10 post-treatment. The Abbott’s formula was used to calculate the efficacies of the isolates, and one-way ANOVA, followed by the Tukey’s test, were used for the statistical analyses. There were significant differences between the fungal isolates and the controls for the mortality of D. gallinae. Beauveria bassiana 1/1-6 was most effective (71.42% mortality), followed by B. bassiana 3/1-2 (66.66% mortality). These two B. bassiana isolates represent potential biological control agents of the poultry red mite, D. gallinae.