Insecticide resistance in Bemisia tabaci from Cyprus

Abstract

A comprehensive study on the Bemisia tabaci (biotype B) resistance to neon- icotinoid insecticides imidacloprid, acetamiprid and thiamethoxam, and pyrethroid bifen- thrin was conducted in Cyprus. The resistance level to eight field-collected B. tabaci populations was investigated. The activities of enzymes involved in metabolic detoxifica- tionandthefrequenciesofpyrethroidandorganophosphatestargetsiteresistancemutations were determined. Moderate to high levels of resistance were detected for imidacloprid (re- sistance factor (RF) 77-392) and thiamethoxam (RF 50-164) while low resistance levels were observed for acetamiprid (RF 7-12). Uniform responses by the Cypriot whiteflies could be observed against all neonicotinoid insecticides. No cross-resistance between the neonicotinoids was detected as well as no association with the activity of the P450 mi- crosomal oxidases. Only imidacloprid resistance correlated with carboxylesterase activity. Low to extremely high resistance was observed for insecticide bifenthrin (RF 49-1243) which was associated with the frequency of the resistant allele in the sodium channel gene but not with the activity of the detoxification enzymes. Finally, the F331W mutation in the acetylcholinesterase enzyme ace1 gene was fixed in allB. tabacipopulations from Cyprus.