Entomopathogenic fungi with biological control potential against poultry red mite (Dermanyssus gallinae, Arachnida:...

The poultry red mite, Dermanyssus gallinae (Arachnida: Dermanyssidae) is a pest that causes significant economic loss in laying hens for which control methods are limited. In this study, the effects of 20 indigenous fungal strains on poultry red mites in chicken farms were investigated. All experiments were conducted under laboratory condition at 28 ± 1 °C and 80 ± 5% humidity. A screening test showed that Metharizium flavoviride strain As-2 and Beauveria bassiana strain Pa4 had the greatest measured effect on D. gallinae at 1 × 10⁷ conidia/ml 7 days after application. In a subsequent does-response experiment, these strains also caused 92.7% mortality at 1 × 10⁹ conidia/ml within the same period. The LC₅₀ of these strains was 5.5 × 10⁴ (95% CI: 0.8-37.5) conidia/ml for As-2 and 3.2 × 10⁴ (95% CI: 0.4-26.0) conidia/ml for Pa4, and their LT₅₀ were 1.94 and 1.57 days, respectively. The commercial Metarhizium anisopliae bioinsecticide Bio-Storm 1.15% WP, used as a comparator, had LC₅₀ and LT₅₀ 1 × 10⁵ (95% CI: 0.1-7.9) conidia/ml and 3.03 (95% CI: 2.4-3.8) days, respectively. It is suggested that mycoacaricides could be developed using the best two fungal strains found in this study (As-2 and Pa4), providing potential for biological control of poultry red mites.