Location: Crop Bioprotection Research
2022 Annual Report
Accomplishments
1. Identified mosquito species that are resistant to insect killing fungi. Not all mosquitoes are equally susceptible to microbial-based biopesticides, and some carry the endosymbiont Wolbachia, a bacterium that can provide the mosquito protection against infection by viruses and bacteria. ARS researchers in Peoria, Illinois, in collaboration with scientists at Illinois State University tested the susceptibility to insect killing fungi of two field mosquitoes, the Asian tiger mosquito (Aedes albopictus) and the house mosquito (Culex pipiens). This study indicated that while Wolbachia does not interfere with the killing activity of insect fungal pathogens, it does impact mosquito overall health, with potential consequences to mosquito reproduction. Furthermore, this study showed that while both mosquito species are killed by insect fungal pathogens, Culex pipiens mosquitoes are highly resistant to the action of one common insect fungal pathogen. This study provides new susceptibility records of two important mosquito vectors in the United States that will guide vector control agencies when selecting the most appropriate biological control agent against these mosquitoes.
2. Determined cedarwood oil is an environmentally friendly biopesticide that kills and repel ticks. Ticks are one of the most important vectors of animal and human pathogens. Their control relies heavily on pesticides but the rapid evolution of pesticide-resistance in ticks underscores the need for new eco-friendly biopesticides. ARS researchers in Peoria, Illinois, tested the toxicity and repellency of cedarwood oil against four different tick species and observed a range of susceptibilities with the most significant toxicity being against the black-legged tick. Exposure to cedarwood oil repelled 80-94% of black-legged ticks, the same rate compared to the traditional DEET-based (N, N-diethyl-meta-toluamide) repellent currently on the market. This study indicates that cedarwood oil is a great candidate for further development of an environmentally friendly acaricide and repellent.
Review Publications
Flor-Weiler, L.B., Behle, R.W., Eller, F.J., Muturi, E.J., Rooney, A.P. 2022. Repellency and toxicity of a CO2-derived cedarwood oil on hard tick species (Ixodidae). Experimental and Applied Acarology. 86:299-312. https://doi.org/10.1007/s10493-022-00692-0.
Ramirez, J.L., Schumacher, M., Ower, G., Palmquist, D.E., Juliano, S.A. 2021. Impacts of fungal entomopathogens on survival and immune responses of Aedes albopictus and Culex pipiens mosquitoes in the context of native Wolbachia infections. PLOS Neglected Tropical Diseases. 15(11). Article e0009984. https://doi.org/10.1371/journal.pntd.0009984.