Pyrethroid and organophosphate resistance in the tobacco whitefly Bemisia tabaci (Homoptera: Aleyrodidae)

Abstract

Eleven strains of Bemisia tabaci (Gennadius), including a laboratory susceptible strain, were bioassayed as adults with three organophosphorus (OP) insecticides, three pyrethroids and one OP/pyrethroid combination. The contemporary strains were from diverse geographical areas and hosts and included examples of the A-, B-, and non-B-biotypes. All recent collections were multi-resistant to these insecticides which have been used extensively for their control. The patterns of cross-resistance for the OPs were clear but less so for the pyrethroids. All populations that resisted profenofos and cypermethrin also resisted the combination of profenofos and cypermethrin. Although the importance of selection pressure on levels of resistance was not easily quantifiable the highly selected populations exhibited the highest levels of resistance. The significant within, as well as between, biotype variation in resistance factors clearly indicated that insecticide resistance and biotype were not directly related. The roles of acetylcholinesterase sensitivity and general esterase activity in resistance to OPs and pyrethroids are discussed.

Bio-rational management of whitefly (Bemisia tabaci) for suppressing tomato yellow leaf curl virus

“…The results are in agreement with the findings of Savary (2000) and Ahmed et al (2001). Imidacloprid (a systemic chloronicotinyl insecticide, Admire) gained major importance for controlling Bemisia tabaci in both field and protected crops, in view of extensive resistance to Organophosphorous, Pyrethroid and Cyclodiene insecticides (Cahil et al, 1995). Admire is currently recommended for the control of whitefly in many countries including the USA.…”

Challenges with managing insecticide resistance in agricultural pests, exemplisfied by the whitefly Bemisia tabaci

“…In many parts of the world, the above factors combined with often intensive insecticide use have led to strong resistance encompassing the great majority of chemical classes (Dittrich et al 1990;Byrne et al 1992;Cahill et al 1995Cahill et al , 1996cDenholm et al 1996;. Resistance in B. tabaci is known to be multi-factorial, Managing resistance in Bemisia tabaci I. Denholm and others 1759 based on both enhanced detoxi¢cation of insecticides and modi¢cations to three of their major target proteins: acteylcholinesterase (AChE), targeted by organophosphates (OPs) and carbamates (Byrne & Devonshire 1993;Anthony et al 1998), the GABA-gated chloride-ion channel, targeted by cyclodienes (Anthony et al 1995), and the voltage-sensitive sodium channel involved in knockdown resistance (kdr) to pyrethroids (M. S.Williamson, personal communication).…”

Control failure of Sri Lankan whitefly (Bemisia tabaci Genn.) is due to high resistance development against recommended insecticides

“…However, the Bandarawela B. tabaci population, which was collected from bean cultivations where etofenprox is not routinely applied, has also shown a high resistance level against etofenprox. Therefore, it is important to further examine the mechanism of cross resistance development to etofenprox in future reported from other countries (Cahill et al, 1995). Both carbosulfan and profenofos are recommended for the and the farmers tend to apply these on other crops also due to the broad spectrum pest control ability of the insecticides.…”