COMPUTER-SIMULATION OF INSECTICIDE RESISTANCE MANAGEMENT STRATEGIES FOR CONTROL OF COLORADO POTATO BEETLE (COLEOPTERA, CHRYSOMELIDAE)

Genetic, ecological, an economic parameters of the Colorado potato bee tle, Leptinotarsa decemlineata (Say) in the northeastern United states were used to construct a computer simulation model of the development of resistance using various insecticide application strategies. There was little or no advantage gained by using either mixture or rotation strategies at the 90% level of control in this simulation. The mixtur e strategy, however, was more effective at reducing resistance develop ment at 97% level of control, particularly if coupled with immigration of susceptible beetles into treated areas or if relative fitness disa dvantage associated with the resistance alleles was increased. Sex-lin kage of the permethrin resistance allele negated the recessiveness of this allele, thus reducing the time for resistance to develop in a pop ulation compared to resistant autosomal alleles. This rare genetic asp ect in the resistance mechanism of Colorado potato beetle to permethri n may be one of the reasons for the rapid loss of control by pyrethroi d insecticides noted throughout many of the potato growing regions of the United States. These findings further support the need to integrat e cultural practices and biological control with insecticides to contr ol Colorado potato beetle and at the same time prevent insecticide res istance development.