Determination of insecticide resistance in Bemisia tabaci (Hemiptera: Aleyrodidae) populations from Punjab, Pakistan.
The whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is one of the most important crop pest among the 100 worst invasive species which threatens agriculture worldwide and poses a serious threat to global food security. The control of B. tabaci depends on the insecticide applications in Pakistan, therefore, monitoring of insecticide resistance is essential for achieving control and for managing resistance. In current study, the field populations of B. tabaci from three crops (cotton, okra and tomato) were collected in five districts (Bahawalpur, Lodhran, Multan, Vehari and Faisalabad) of Punjab, Pakistan in 2017, 2018 and 2019. A leaf- dip bioassay was used to determine the resistance of these populations to five insecticides (Diafenthiuron, spirotetramat, deltamethrin, abamectin and nitenpyram). A very low to low level of resistance to nitenpyram, spirotetramat, and abamectin, whereas moderate to high level of resistance to diafenthiuron and deltamethrin were detected in all populations of B. tabaci compared with the laboratory susceptible strain. The resistance ratios ranged 16.37 to 26.07-fold for diafenthiuron, 52.76 to 73.85-fold for deltamethrin, 3.85 to 7.79-fold for nitenpyram, 3.62 to 13.75-fold for spirotetramat and 5.19 to 9.09-fold for abamectin. The presented results will be helpful to make decision on the proper usage of insecticides against whitefly control and to reduce the development of insecticide resistance.