Lethal effects of commercial Kaolin Dust and Silica Aerogel Dust with and without botanical compounds on Horn Fly eggs, larvae, pupae, and adults in the laboratory

Authors: Showler, Allan; Harlien, Jessica

Submitted to: Journal of Medical Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/22/2021
Publication Date: 8/17/2021
Citation: Showler, A., Harlien, J.L. 2021. Lethal effects of commercial Kaolin Dust and Silica Aerogel Dust with and without botanical compounds on Horn Fly eggs, larvae, pupae, and adults in the laboratory. Journal of Medical Entomology. https://doi.org/10.1093/jme/tjab140.
DOI: https://doi.org/10.1093/jme/tjab140

Interpretive Summary: The horn fly is an important bloodsucking external parasite of cattle throughout much of the world. The fly is mostly controlled using conventional synthetic chemical insecticides but as concerns about resistance increase, alternative tactics are receiving heightened research attention. Desiccant dusts Surround WP, a kaolin clay-based powder; CimeXa, comprised of silica aerogel; and Drione and EcoVia, comprised of silica aerogel + pyrethrins and thyme oil, respectively, were assessed for their lethal effects against horn fly eggs, larvae, pupae, and adults, under laboratory conditions. Although Surround and CimeXa did not prevent egg hatching and (when mixed with manure) pupal development, the two products were associated with moderate reductions of emerged adults, and with complete adult contact mortality by 6 h and 24 h, respectively. Drione and EcoVia eliminated egg hatching, pupal development, and adults within 15 min to 1 h, respectively, whether the flies were exposed to treated filter paper substrate or exposed by immersion in the dusts. Implications for horn fly control and advantages of inert desiccant dust formulations are discussed.

Technical Abstract: The horn fly, Haematobia irritans irritans (L.) (Diptera: Muscidae), is an important bloodsucking ectoparasite of cattle throughout much of the world. The fly is mostly controlled using conventional synthetic insecticides but as concerns about resistance increase, alternative tactics have come under heightened scrutiny. Desiccant dusts Surround WP, a kaolin clay-based wettable powder; CimeXa, comprised of silica aerogel; and Drione and EcoVia, comprised of silica aerogel + pyrethrins and thyme oil, respectively, were assessed for their lethal effects against horn fly eggs, larvae, pupae, and adults, under laboratory conditions. Although Surround and CimeXa did not prevent egg hatching and (when mixed with manure substrate) pupal development, the two products were associated with moderate reductions of emerged adults, and with complete adult contact mortality within 6 h and 24 h, respectively. Drione and EcoVia eliminated egg hatching, pupal development, and adults within 15 min to 1 h, respectively, whether the flies were exposed to treated filter paper substrate or exposed by immersion in the dusts. Implications for horn fly control and advantages of inert desiccant dust formulations are discussed.