The efficacy of fluazuron in the management of blowfly strike in sheep.

The blowflies Lucilia spp. and Chryomya spp. feature prominently as a leading cause of myiasis and production losses in sheep in South Africa. With chemical means of preventing and treating blowfly strike being a common manner of control, new molecules or formulations effective against blowfly strike are needed as resistance becomes more of a problem. For this study we evaluated the potential of topical application of fluazuron on sheep as an additional means to control blowflies. When pure fluazuron was applied to raw meat at the recommended dose for cattle, significant effects on adult fly development were observed. However when applied topically to post-mortally collected sheep pelts at the same dose rate, no significant effects were observed on larval repellence or larval development with fly development progressing as expected. A subsequent pharmacokinetic study showed virtually no systemic absorption together with significant wool binding. Despite demonstrating that fluazuron was effective against blowfly larvae, wool binding of the molecule preclude its use.