Haematobia Irritans - Management

Management

Due to the level of damage an infestation can result in, much has been done over the years in the effort to manage, reduce, and eliminate the horn fly. Traditional methods were through the use of pour-ons, backrubbers and face powder bags, with products such as Co-Ral which is available as dust for face/horn flies. Self-applicator methods such as dust bags and backrubbers are used mainly for range or pasture herds, and are placed so that the animal cannot avoid coming into contact with it, such as at a gate through which animals pass. More recently, control of the horn fly by using ear tags on cattle has been extremely successful. The ear tags are made of a PVC matrix impregnated with pyrethroid, and can be effective for between 16 to 24 weeks. Originally, the ear tags were developed and used against such pests as ticks and by 1983 50% of cattle had ear tags. Long periods of such dosing resulted in the elimination of 95-99% of susceptible flies, but this strong selection pressure ended up resulting in the development of resistant strains of the flies. To combat this, the use of organophosphates and piperonyl butoxide as a synergist are now recommended to be alternated with pyrethroid to help slow resistance. In addition, methoprene in the form of sustained release bolus (a rounded mass of food or pharmaceutical preparation ready to swallow) inhibits the emergence of an adult insect from a pupal case or an insect larvaa from an egg for up to 7 months. New research (2011) has shown essential oil vapors from 16 species of Eucalyptus to have toxicity against Haematobia irritans.