Currently, helicopters are used to spray a biological material into the riffle areas of streams and rivers to suppress larval populations before they emerge into adults. DEP targets only a few species of black flies in its suppression efforts. Gnat nuisance problems commonly observed in the spring are not targeted for suppression because their life cycle is short-lived. DEP targets black fly species that produce multiple generations which occur when recreational activities are at their peak. The goal of the Black Fly Suppression Program is to reduce the adult populations to tolerable pest levels during the summer recreational season.
Funding comes from a combination of state legislature appropriations and participating counties.
In 1997, it is anticipated that 42 streams and rivers in 28 counties will be enrolled in the program. DEP monitors selected stream areas for the presence of black fly populations. Stream flow conditions, water temperatures and larval counts determine when and where spraying occurs. The purpose of spraying is to kill larvae of the black flies before they emerge into adults. Monitoring also occurs after spraying to determine the effectiveness of the treatment.