Resistance and cross-resistance of Bemisia tabaci to three commonly used insecticides in the tomato greenhouses of the Souss Valley of Morocco

In this study, 10 populations of whiteflies B. tabaci were collected from tomato greenhouses in the Souss valley of Morocco and bioassayed for resistance to three commonly used insecticides (Imidacloprid, Thaimethoxam and Methomyl). Using Leaf-Dip bioassay, we concluded that all populations tested were resistant to Imidacloprid and Thiamethoxam. The resistance factors registered were varied between 2 to 39 and 2 to 12, respectively. The levels of resistance to Methomyl were slightly low and showed a moderate variation between 1 and 4. The analyses of correlation showed a very significant cross-resistance of B. tabaci to this two Neonicotinoids. The predominant biotype noted in this study is biotype Q with the presence of some B. tabaci populations expressed a variant of biotype Q.