Laboratory trials of fatty acids as repellents or antifeedants against houseflies, horn flies and stable flies (Diptera: Muscidae).
BACKGROUND
Straight-chain, saturated fatty acids (particularly C8, C9 and C10) have some known behavioral effects on insects such as mosquitoes, and were tested in combination for potential repellency/antifeedant activity in bioassays against three significant muscoid flies of medical/veterinary importance: houseflies, horn flies and stable flies.


RESULTS
Mixtures of C8, C9 and C10 (1:1:1; 15% total actives in formulation) were highly repellent to houseflies and horn flies at or below 1 mg formulation cm(-2). Repellency time varied from < 1 day for houseflies to usually at least 3 days for horn flies. Individual longer-chain-length fatty acids were tested, and C11 repelled houseflies for up to 5-8 days, while C12 lasted 2 days. Minimum statistically significant repellency levels of the C8, C9 and C10 mixture (3 h after application) against horn flies were 0.06-0.12 mg cm(-2). A liquid formulation of the 15% C8, C9 and C10 mixture in a silicone oil carrier (at 2.8 mg AI cm(-2)) was highly repellent against hungry stable flies in a blood-feeding membrane bioassay for at least 8 h.


CONCLUSIONS
The low toxicity and reasonable activity and persistence of these carboxylic acids make them good candidates for development as protective materials against pest flies in livestock settings.
Mullens
Bradley A
BA
Department of Entomology, University of California, Riverside, CA 92521, USA. mullens@mail.ucr.edu
Reifenrath
William G
WG
Butler
Sarah M
SM
D000818:Animals; D005227:Fatty Acids / Q000737:chemistry / Q000494:pharmacology*; D005247:Feeding Behavior / Q000187:drug effects; D007300:Insect Control; D007302:Insect Repellents / Q000494:pharmacology*; D009117:Muscidae / Q000187:drug effects* / Q000502:physiology*
D005227:Fatty Acids; D007302:Insect Repellents