Insecticide resistance monitoring in whitefly (Bemisia tabaci) (Hemiptera: Aleyrodidae) in Oman


Shah, R., Al-Sadi, A.M., Scott, I.M., AlRaeesi, A., AlJahdhami, A.A. (2020). Insecticide resistance monitoring in whitefly (Bemisia tabaci) (Hemiptera: Aleyrodidae) in Oman. Journal of Asia Pacific Entomology, [online] 23(4), 1248-1254.

Plain language summary

A survey was completed on the state of insecticide resistance in sweet potato whitefly populations in Oman. The findings indicate that all whitefly populations studied have low resistance to 3 classes of insecticides. However, 2 populations have become less sensitive to a pyrethroid insecticide and there is a possible risk of cross-resistance with other insecticide products. This information is important to vegetable growers and the agrichemical industry in Oman.


The sweet potato whitefly, Bemisia tabaci Gennadius, is an important insect pest of many crops including vegetables through direct feeding damage and as a vector of several plant viruses. Intensive use of insecticides has led to the development of insecticide resistance in global B. tabaci populations. This study was conducted to establish susceptibility levels to deltamethrin, thiamethoxam and pyriproxyfen in seven geographically different populations of B. tabaci MEAM1 adults in Oman. All B. tabaci populations showed very low to low level of resistance (2.1–12.3 fold) to deltamethrin. All B. tabaci populations showed no resistance to very low level of resistance to thiamethoxam (2.2–6.2 fold) and pyriproxyfen (2.4–3.5 fold). A likelihood analysis showed the possibility for control failure in two populations (Barka and Salalah) to deltamethrin, however, no possible failure was detected in all populations for thiamethoxam and pyriproxyfen. An insecticide resistance dynamics study in one population (SQU-1) showed a loss in susceptibility to deltamethrin with increase in the LC50 value from 25.1 mg L−1 to 84.5 mg L−1 between 2017 and 2019 resulting in 5.3 fold increase in RF. The study results determined that several B. tabaci populations are at the initial stages of resistance development to deltamethrin and cross-resistance with thiamethoxam and pyriproxyfen. Vegetable farmers in Oman, the Barka and Salalah regions in particular, should be cautious in the repeated use of one class of insecticide alone.

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