A Review of Ecological Factors Associated with Wild Host Plants as Refuges for Suppressing Pesticide Resistance in Agricultural Arthropod Pests

Arthropod pests continue to occur throughout the year by inter-plant movement and dispersal between cultivated host plants that are applied with pesticides and wild host plants that serve as refuges in the area of cultivation. This paper reviews the relationship between the host range and status of pesticide resistance in agricultural arthropod pests in Japan. The decisive factors for determining the development of pesticide resistance were concluded with attention paid to wild host plants as refuges. The arthropod pests that developed pesticide resistance were as follows: (1) monophagous species infesting cultivated crops treated with pesticides, (2) polyphagous species with a host range restricted to cultivated plants lacking wild host plants, and (3) certain populations of polyphagous species develop resistance in habitats such as tea fields and greenhouses with year-round cultivation because they are relatively isolated from the surrounding populations that do not develop resistance due to the abundance of refuges. In all cases, pest populations inhabit environments where they are restricted to mate with the susceptible populations from refuges of wild host plants.