Whiteflies at the Intersection of Polyphagy and Insecticide Resistance

Abstract

Abstract The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most damaging, polyphagous insect pests of agricultural cropping systems around the world. Insecticide control is one of the main tactics used to mitigate damage and crop injury caused by the species. Similarly, plant chemical defenses are primary natural mechanisms that reduce attacks from whiteflies. Like all Sternorrhyncha insects, whiteflies have piercing/sucking mouthparts and feed on phloem sap from vascular plants through a stylet. Therefore, if this insect can overcome the physical barriers of the plant and pierce the vascular bundle, the main remaining barriers to nutrition uptake and utilization are phytochemicals that might exhibit some degree of toxicity toward the insect. Bemisia tabaci has been reported to feed on over 1,000 plant species representing an enormous range of phytochemicals to which whiteflies are potentially exposed. Recently, whiteflies were shown to have acquired a gene from plants to detoxify the plant’s phenolic glycosides that are usually toxic. Additionally, host plants have been shown to alter the response of a single whitefly population to insecticides. Herein, we review possible interactions between the highly polyphagous B. tabaci, the potential phytochemicals associated with its extensive plant host range, and the main chemical insecticides used to control this pest. This review aims to provide a conceptual framework for studying possible biological interactions between the insect, host plant, and insecticidal toxins used to control this pest at the mechanistic and population selection levels.