The chemical and physical nature of the manure and other materials in the breeding areas cause a rapid breakdown of the insecticide. There also is a much greater chance for the development of insecticide resistance when the immature fly population is exposed to these treatments. However, under some conditions, larvicides may be the only workable solution. Fly breeding areas that are too wet for the use of cleaning equipment may have to be treated with sprays to reduce fly populations. The same is true of stored manure that has been penetrated with moisture.
Baits are useful only for house flies or blow flies.
Stable flies feed only on blood and are not attracted to baits. There are commercially available baits in dry or liquid forms. Residual insecticides suitable for use around livestock can be mixed with sugar and used as baits. Baits should be applied only in locations inaccessible to animals or children. Baits and dead flies should be removed at weekly intervals and the bait replaced for best results.