Resistance of Colorado potato beetle (Leptinotarsa decemlineata Say) to commonly used insecticides in Iran

Abstract

The Colorado potato beetle (CPB, Leptinotarsa decemlineata Say), is a major pest of potatoes in Iran and many other parts of the world. Injury is caused when adults and larvae feed on the foliage and stems of potato plants, resulting in poor yields and/or plant death. Adult beetles can also vector plant diseases. Historically, the CPB been controlled using different insecticides, but it is currently resistant to nearly all classes of insecticides and remains a serious pest in many parts of the world. All of the resistance mechanisms reported in insects have been demonstrated in CPB. L. decemlineata invaded Iran in the early 1980s, probably through the importation of infested potatoes. It has caused significant damage to potato crops in affected areas, and it accordingly remains a major threat to Iranian potato production. Regrettably, no IPM programs have been developed for managing CPB infestations in Iran. Furthermore, there are no organized CPB resistance monitoring programs in Iran, and the recommended insecticides for CPB control, endosulfan and phosalon, have not changed in over 22years. Anecdotal evidence from local farmers suggests a reduction in the efficacy of control of CPB by commonly used insecticides, probably due to the reduced susceptibility to these insecticides. Given the economic significance of L. decemlineata infestations, the increasing prevalence of resistance in this species, the rate of spread of infestations, and the extent of the area infested, there is an urgent need to develop effective and sustainable integrated pest management programs for CPB in Iran.