The battle against flies is constant, but there are ways to reduce these costly and irritating pests — without toxic chemicals. There are several types of pest flies, with different habits and behavior, so a combination of tactics is usually most effective when trying to eliminate or reduce flies. House flies and stable flies (the latter are aggressive biters, tormenting horses and cattle) breed in manure and rotting organic matter such as old hay and bedding. Horse flies and deer flies breed in swampy areas and black flies breed in flowing water.

In the Old World two insects, called asparagus beetles, have been known as enemies of the asparagus since early times. In the year 1862 the common asparagus beetle was the occasion of considerable alarm on asparagus farms in Queens County, N.Y., where it threatened to destroy this, one of the most valuable crops grown on Long Island. Subsequent inquiry developed the fact that the species had begun its destructive work at Astoria, near New York City, in 1860, and it is now conceded that it was introduced in this locality about 1856.