New model confirms refuge values
Researchers from the US University of Arizona (Tucson) and others have developed a new method to assess the effectiveness of refuge strategies in delaying the emergence of pests resistant to insecticides. The method is based on results of an eight-year, large-scale study involving 84 cotton fields in central Arizona and takes into account variations in surrounding crop types and distances between treated fields and refuge areas. The study looked at the effects of the insecticide, pyriproxyfen, on whiteflies ( Bemisia tabaci). Data from the first four years of the study were used to develop spatially explicit statistical models that identified the crops affecting local variations in pest resistance and the maximum range of any effects.