Biocontrol of pigeon tick Argas reflexus (Acari: Argasidae) by entomopathogenic fungus Metarhizium Anisopliae (Ascomycota: Hypocreales)

Abstract

The pigeon tick Argas reflexus is a pathogen-transmitting soft tick that typically feeds on pigeons, but can also attack humans causing local and systemic reactions. Chemical control is made difficult due to environmental contamination and resistance development. As a result, there is much interest in increasing the role of other strategies like biological control. In this study, the efficacy of three strains (V245, 685 and 715C) of entomopathogenic fungus Metarhizium anisopliae for biological control of three life stages of pigeon tick A. reflexus including eggs, larvae, engorged and unfed adults was investigated under laboratory conditions. Five concentrations of different strains of M. anisopliae ranging from 10 3 to 10 7 conidia/ml were used. All fungal strains significantly decreased hatchability of A. reflexus eggs. Strain V245 was the most effective strain on the mortality of larval stage with nearly 100% mortality at the lowest concentration (10 3 conidia/ml) at 10 days post-inoculation. The mortality rate of both engorged and unfed adult ticks were also increased significantly exposed to different conidial concentrations compared to the control groups (P < 0.05) making this fungus a potential biological control agent of pigeon tick reducing the use of chemical acaricides.

Fungi and Oomycetes–Allies in Eliminating Environmental Pathogens

“…A pronounced acaricidal effect on adult females of Dermanyssus gallinae was noted in B. bassiana CD1123 conidia, applied at a concentration of 10 9 / ml [120]. An ovicidal, larvicidal, and adulticidal effect against Argas reflexus ticks has been reported in V245, 685, and 715C of Metarhizium anisopliae, the first strain being the most pathogenic [121]. High mortality, observed starting one week after application, was also recorded in females of Rhipicephalus annulatus exposed to the action of Metarhizium anisopliae [122].…”