Variation in susceptibility to insecticides in Bemisia tabaci biotype B fed on different hosts

Abstract

Bemisia tabaci (Gennaadius) biotype B is one of themost important pests due to the number of hosts and economic lossesit produces. Its control is based on the application of chemicals,which has led to resistance problems. However, the host may also influencethe induction of resistance to pesticides. Therefore, the presentstudy evaluated the susceptibility of populations of B. tabaci biotypeB developed indifferent hosts to three insecticides belonging todifferent toxicological groups. Bemisia tabaci biotype B populationswere collected and reared in six different hosts (three crops and threeassociated weeds: Solanum lycopersicum, Solanum nigrum, Phaseolusvulgaris, Melampodium divaricatum, Cucurbita spp. and Heliotropiumangiospermun) in the state of Chiapas, Mexico. By using the dippingbioassay method with nymphs five- to eight-days-old, the CL50 wasdetermined. The higher values of bifenthrin were recorded on M.divaricatum and S. nigrum with 278.74 and 177.76 ppm, respectively.For imidacloprid, S. lycopersicum and S. nigrum recorded 179.59 and168.59 ppm, respectively. Finally for endosulfan, M. divaricatum andH. angiospermun registered values of 134.57 and 156.52 ppm, respectively.Therefore, the host affected the tolerance of Bemisia tabaci biotypeB to insecticides, primarily because of the induced resistance ofeach of the plant species that served as hosts, providing the ability todetoxify the various pesticides by using enzymes.