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ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Mosquito and Fly Research » Research » Publications at this Location » Publication #336762

Research Project: Management of Filth Flies

Location: Mosquito and Fly Research

Title: Discovery, development, and evaluation of a horn fly-isolated (Diptera: Muscidae) Beauveria bassiana (Hypocreales: Cordyciptaceae) strain from Florida, U.S.A

item HOLDERMAN, CHRISTOPHER - University Of Florida
item WOOD, LOIS - University Of Florida
item Geden, Christopher - Chris
item KAUFMAN, PHILLIP - University Of Florida

Submitted to: Journal of Insect Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/18/2017
Publication Date: 4/3/2017
Citation: Holderman, C.J., Wood, L.A., Geden, C.J., Kaufman, P.A. 2017. Discovery, development, and evaluation of a horn fly-isolated (Diptera: Muscidae) Beauveria bassiana (Hypocreales: Cordyciptaceae) strain from Florida, U.S.A. Journal of Insect Science. 17(2):51:1-6.

Interpretive Summary: Horn flies are among the most economically injurious pests of the US cattle industry. The flies feed on blood and are often present in high enough numbers to cause reduced weight gain and milk production. High levels of insecticide resistance in the fles has prompted efforts to develop alternative control methods. One of these is the entomopathogenic fungus Beauveria bassiana. In this study, scientists at the Unversity of Florida and USDA-ARS in Gainesville FL discovered and isolated a strain of B. bassiana from horn flies collected from a Florida cattle farm. Initiaal tests with the strain were promising, and an attempt was made to select the B. bassiana in order to shorten the amount of time it takes to kill the flies. Although there was little change in death times after the selection, the selected strain consistently produced large numbers of spores. Further exploration may reveal other strains with good growth properties that will kill flies faster than the current strain.

Technical Abstract: The horn fly is an important cattle pest and traditionally has been managed using insecticides; however, many horn fly populations are insecticide-resistant in the United States. Use of alternative control techniques has been limited because of the challenges of managing a fly pest on pastured cattle. After the discovery of a wild horn fly infected with Beauveria bassiana in Florida, the fungus was cultured and evaluated for efficacy against laboratory-reared horn flies. This fungal strain was selected for increased virulence by passage through laboratory reared horn fly hosts to shorten interval from infection to fly death and subsequent conidia formation, properties important to future use of the fungus as a biological control agent against horn flies. After 7 passages through horn fly hosts, fly mortality was not significantly accelerated as evaluated through LT50 values, but conidia were readily produced from these killed flies. Although further development is needed to improve fungal efficacy, this fungal strain holds promise as a biological control agent for inclusion in horn fly integrated pest management programs.