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Submitted to: Medical and Veterinary Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/14/2011 Publication Date: 3/12/2012 Citation: Liu, S.S., Li, A.Y., Lohmeyer, K.H., Perez De Leon, A.A. 2012. Effects of pyriproxyfen and buprofezin on immature development and reproduction in the stable fly. Medical and Veterinary Entomology. 26:379-385. Interpretive Summary: The stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), is a damaging pest affecting livestock in dairies and feedlots. Currently, there is a lack of effective methods for controlling stable flies on pastured cattle. Pyriproxyfen and buprofezin are insect growth regulators (IGRs) that have been used to control many insect pest species. Their utility in stable fly control has not been investigated in the past. A study was conducted at the USDA, ARS, Knipling-Bushland U.S. Livestock Insects Research Laboratory to evaluate the potential of using such IGRs for the control of stable flies and other biting flies affecting cattle. A manure bioassay technique was used to test effects of both pyriproxyfen and buprofezin against the immature stages, and a topical treatment method was used to test the effect of pyriproxyfen on female oviposition and egg hatching. Results indicated that pyriproxyfen was effective against stable fly larvae (LC50 = 0.002 ppm) and a significant reduction in adult emergence (up to 89.81%) can be achieved. Buprofezin was less effective (LC50 = 18.92 ppm). Topical treatment of pyriproxyfen on young female adult flies (1-3 day old) had significant negative effects on both oviposition and egg hatch. Pyriproxifen had little effect on five day old female flies. The results generated from this study suggest pyriproxyfen has the potential to be used as part of an integrated stable fly management program. Technical Abstract: The stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae) is one of the most significant biting flies affecting cattle. Use of traditional insecticides for stable fly control has only limited success due to the insect’s unique feeding behaviors and immature development sites. A laboratory study was conducted to evaluate the effects of two insect growth regulator (IGR), pyriproxyfen and buprofezin, on the development of immature stages of the stable fly and the effects of pyriproxyfen on oviposition and egg-hatch. Both pyriproxyfen and buprofezin had significant inhibitory effects on immature development when larvae were reared on manure treated with different IGR concentrations. The LC50s of pyriproxyfen and buprofezin were 0.002 ppm and 18.92 ppm, respectively. Pyriproxyfen at the concentration of 0.005 ppm caused 89.81% reduction in adult emergence, while buprofezin at 75 ppm achieved 75.4 % reduction in adult emergence. Topical treatment of adult females with different doses of pyriproxyfen had significant effects on both female oviposition and egg hatching when the females were treated at a younger age (1-3 day old), and the effect was dose-dependent. A reduction (up to 74%) in the number of eggs laid per female was achieved at higher doses (2-8 µg/fly). A significant reduction (77%) was observed only at the highest dose (8 µg/fly) when 5 day old females were treated. Pyriproxyfen also significantly reduced egg hatch in a dose dependant manner when females were treated at a younger age (1-3 d). Little effect on egg hatch was observed when 5 day old females were treated. Results from this study indicate pyriproxyfen has the potential to be used as part of an integrated stable fly management program. |
