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Many damaging agricultural pests can, in addition to their direct feeding damage, acquire and transmit plant pathogens. Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is considered a ‘supervector’ of disease-causing plant pathogens and viruses. One of the most damaging of these is Tomato yellow leaf curl virus (TYLCV), a circulatively transmitted begomovirus than can extensively damage field and greenhouse crops. Because sustained feeding periods are necessary to acquire and transmit circulatively transmitted viruses, pesticides that, in addition to their direct lethality, suppress feeding in surviving individuals may be particularly effective in decreasing viral transmission. We assessed the impact of sulfoxaflor, a sulfoximine insecticide, on the settling preference, feeding, and viral transmission of TYLCV-carrying B. tabaci on tomato. We found that viruliferous B. tabaci avoided both settling and feeding on sulfoxaflor-treated plants, and that sulfoxaflor virtually eliminated the transmission of TYLCV by B. tabaci. The antifeedant properties of sulfoxaflor have previously been reported in other pest systems; our results document similar effects on viruliferous B. tabaci and demonstrate that this pesticide can reduce TYLCV transmission by surviving individuals.

Pesticides primarily affect target organisms via direct toxicity, but may also alter the feeding behaviors of surviving individuals in ways that alter their effect on host plants. The latter impact is especially important when pests can transmit plant pathogens. The Mediterranean (MED) population of the sweetpotato whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) transmits Tomato yellow leaf curl virus (TYLCV), a pathogen that can be economically devastating in field and greenhouse cropping systems. We first assessed the impact of sublethal (LC15) and label concentrations of flupyradifurone, a butenolide-derived insecticide, on the feeding behavior of TYLCV-infected MED on tomato. We next measured the effect of flupyradifurone on plant TYLCV load, vector transmission efficiency, and MED survival. Both the LC15 and label flupyradifurone concentrations dramatically altered MED feeding and caused the near cessation of both salivation and phloem ingestion (necessary for viral transmission and acquisition, respectively). Both concentrations also significantly reduced plant TYLCV load, and the label rate of flupyradifurone sharply decreased TYLCV transmission while killing >99% of MED. As the first report of pesticide-induced changes in the feeding behavior of viruliferous Bemisia, our findings highlight the potential importance of chemically driven feeding cessation in the control of TYLCV and other Bemisia-transmitted plant pathogens.

Plant pathogens and insect herbivores often share hosts under natural conditions. Hence, pathogen-induced changes in a host plant can affect the herbivore and vice versa. Even though plant viruses are ubiquitous in the field, little is known about plant-mediated interactions between viruses and nonvector herbivores. Here we tested whether the performance of the sweet potato whitefly, Bemisia tabaci (Gennadius) biotype Q, was altered when raised on pepper infected with Tomato spotted wilt virus (TSWV). TSWV infection reduced B. tabaci fecundity and longevity and increased B. tabaci developmental time but did not affect the insect's survival or female body lengths. Our results demonstrate that TSWV infection can decrease the fitness of B. tabaci biotype Q on pepper plants.

The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), causes severe crop losses to many crops. The worst of these losses are often associated with the invasion and establishment of biotypes B and Q of this pest. Previous research in 2007 showed that biotype Q occurred with other biotypes in most field populations in China. To determine the current status of the biotype composition in the field, an extensive survey covering mainly eastern parts of China was conducted in 2009. Using polymerase chain reaction primers specific for the mitochondrial cytochrome oxidase I of biotypes B and Q and gene sequencing, we determined the biotypes composition in 61 whitefly populations and their distribution across 19 provinces in China. Our research revealed that only biotypes B and Q have been found in the field in 2009 in China. Among them, biotype Q was dominant in 44 locations (100.0%) and biotype B was dominant in 17 locations (100.0%). The current survey indicates that biotype Q has rapidly displaced biotype B in most locations in China.