Predation on the horn fly by Hister bruchi

Hister bruchi Lewis, a histerid species from Argentina, was evaluated in the laboratory to determine its potential as a biological control agent for immature stages of the horn fly, Haematobia irritans (L.). When immature stages of the horn fly were exposed to varying numbers (one - five) of adult beetles, horn fly population reductions were significantly greater at all levels compared with controls. However, increasing the predator-prey ratio greater than 1:50 had no significant effect on numbers of prey consumed by the beetles. This South American predator was more effective on the larval-pupal stages of the horn fly than on the egg stage.