International Journal of Nematology and Entomology ISSN 2756-3839 Vol. 7 (4), pp. 001-005, April, 2020. © International Scholars Journals
Full Length Research Paper
Pathogenicity of the entomopathogenic fungus Metarhizium anisopliae to the red-legged tick, Rhipicephalus evertsi evertsi
Marius Hedimbi1*, Godwin P. Kaaya, G.P2, Michael Samish, M3, Galina Gindin3 and Itamar Glazer3
1Department of Biological Sciences, University of Namibia, Private Bag 13301, Windhoek, Namibia.
2Department of Animal Science, University of Namibia, Private Bag 13301, Windhoek, Namibia.
3ARO, The Volcani Centre, P. O. Box 6, Bet Dagan 50250, Israel.
Accepted 18 March, 2020
Rhipicephalus evertsi evertsi is an economically-important tick of livestock in Africa mainly due to its ability to transmit Babesia equi to horses, Anaplasma marginale to cattle and to cause paralysis in lambs, adult sheep and calves. This study investigated the pathogenicity and hence the bio-control potential of Metarhizium anisopliae to eggs and all other off-host stages of R. e. evertsi. The eggs and larvae were infected by placing them on filter paper wetted with conidial suspension. Tick instars were infected by dipping in M. anisopliae suspenssion (1×10 3–10 8 conidia/ml) and incubated together with the eggs at 25°C and 100% relative humidity (RH). The m ortality of eggs and all tick stages tested increased with increasing conidial concentration and were higher (P>0.05) in conidia formulated in oil than in those formulated in water. For instance, the LC50 in unfed larvae was 1×10 4 conidia /ml in oil formulation and 1×10 5 conidia /ml in water formulation. No difference was observed in mortality between fed and unfed tick stages.
Key words: Rhipicephalus evertsi evertsi, Metarhizium anisopliae, formulation, mortality, biological control.