Laboratory selection of greenhouse whitefly for resistance to malathion

Abstract

A strain of the greenhouse whitefly (Trialeurodes vaporariorum Westwood (Homoptera: Aleyrodidae)) with a history of insecticide exposure was selected with malathion sufficient to cause 80-90% mortality. After 13 generations, malathion resistance had increased 55-fold, and a slight (1.7 X) increase in resmethrin resistance was noted. There was no cross-resistance to dichlorvos, methomyl or permethrin.DEF (S,S,S-tributyl phosphorotrithioate) synergized malathion (18.6 ×) and resmethrin (3.4 X). This suggested involvement of esterases in resistance of whiteflies to insecticides.Throughout selection, the resistant strain showed a high proportion of females. Virgin females of both resistant and parent strains produced males only.

Delphastus catalinae and Coleomegilla maculata lengi (Coleoptera: Coccinellidae) as biological control agents of the greenhouse whitefly, Trialeurodes vaporariorum (Homoptera: Aleyrodidae)

“…The greenhouse whitefly, Trialeurodes vaporariorum (Westwood) is one of the main pests of greenhouses around the world 1, 2. The whitefly is resistant to an array of chemical pesticides3, 4 including insect growth regulators 5. In vegetable greenhouses, the parasitoids Encarsia formosa Gahan and Eretmocerus spp6–8 and the mirid bugs Macrolophus caliginosus (Wagner) and Dicyphus hesperus Knight2, 9 are successfully used to control the pest all season long.…”

Comparative Growth and Efficacy of Trinidadian Stra Comparative Growth and Efficacy of Trinidadian Strains Trinidadian Strains of Isaria Fumosorosea Blastospores Blastospores for Controlling for Controlling for Controlling Trialeurodes Vaporariorum Trialeurodes Vaporariorum on Bean Plants Bean Plants

“…The GW is now an emerging threat responsible for transmitting criniviruses to several vegetables and fruits grown in North America (Wintermantel, 2004). Use of chemical insecticides is considered the primary mode of controlling GW; however, there are several reports suggesting genetic resistance has developed in populations of GW with many of the chemicals being used both in the greenhouses and in the fields (Elhag and Horn, 1984;Omer et al, 1992;Sanderson and Rousch, 1992;Gorman et al, 2002;Karatolos et al, 2010Karatolos et al, , 2012. In order to forestall or delay the development of resistance in GW against a specific chemical, it is important to find an alternate approach which is effective and environmentally compatible.…”