Insecticide resistance in Bemisia tabaci biotype Q (Hemiptera: Aleyrodidae) from China

Dispersion of invasive biotypes of the tobacco whitefly, Bemisia tabaci, has led to protracted crop protection constraints in numerous countries over recent decades. These polyphagous, highly efficient vectors of plant viruses present an intractable problem as they frequently carry a diverse suite of insecticide resistance mechanisms. In many areas of China, native biotypes have been supplanted by the invasive and globally widespread biotype B since the 1990s. More recently, biotype Q has established, posing a new and more potent threat to agricultural production systems throughout the country. Insecticide resistance profiles for a range of Chinese B. tabaci strains covering biotypes B and Q were examined, to establish the potential for insecticides to play a pivotal role in biotype competition and ultimate displacement. Commonly used compounds including pyrethroids, neonicotinoids, abamectin and pyriproxyfen were targeted as widespread use is pre-requisite to drivers of population dynamics on a national scale.It was found that across several strains, both biotypes responded similarly against pyrethroids, abamectin and pyriproxyfen. However, their responses to three commercially available neonicotinoids were consistently contrasting. Biotype B strains remained largely susceptible to acetamiprid, imidacloprid, and thiamethoxam, whereas biotype Q strains expressed 20–170 fold resistance to these insecticides. It appears that in China the use of neonicotinoid insecticides has the potential to select for biotype Q within mixed biotype areas, contributing to the establishment and prevalence of this relatively recent introduction.