Arthropod vectors are responsible for a multitude of human and animal diseases affecting poor communities in sub-Saharan Africa. Their control still relies on chemical agents, despite growing evidence of insecticide resistance and environmental health concerns. Biorational agents, such as the entomopathogenic fungus
Metarhizium anisopliae, might be an alternative for vector control. Recently, the
M. anisopliae isolate ICIPE 7 has been developed into a commercial product in Kenya for control of ticks on cattle. We were interested in assessing the potential of controlling not only ticks but also disease-transmitting mosquitoes and tsetse flies using cattle as blood hosts, with the aim of developing a product for integrated vector management. Laboratory bioassays were carried out with
M. anisopliae, isolate ICIPE 7 and isolate ICIPE 30, to compare efficacy against laboratory-reared
Anopheles arabiensis. ICIPE 7 was further tested against wild
Glossina fuscipes and
Rhipicephalus spp. Dose–response tests were implemented, period of mosquito exposure was evaluated for effects on time to death, and the number of spores attached to exposed vectors was assessed. Exposure to 10
9 spores/mL of ICIPE 7 for 10 min resulted in a similar mortality of
An. arabiensis as exposure to ICIPE 30, albeit at a slower rate (12 vs. 8 days). The same ICIPE 7 concentration also resulted in mortalities of tsetse flies (LT
50: 16 days), tick nymphs (LT
50: 11 days), and adult ticks (LT
50: 20 days). Mosquito mortality was dose-dependent, with decreasing LT
50 of 8 days at a concentration of 10
6 spores/mL to 6 days at 10
10 spores/mL. Exposure period did not modulate the outcome, 1 min of exposure still resulted in mortality, and spore attachment to vectors was dose-dependent. The laboratory bioassays confirmed that ICIPE 7 has the potential to infect and cause mortality to the three exposed arthropods, though at slower rate, thus requiring further validation under field conditions.
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