Advances in managing whiteflies, from synthetic to biological controls

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) remains a pest of crop production worldwide. This whitefly is adaptable and has displayed many cases of insecticide resistance to many commonly used chemistries in multiple IRAC classes. Many control methods have been employed, from insecticide treatments to biological control agents to protect high-value crops. Therefore, shifting towards alternative approaches such as host plant manipulation or other biologicals and microbials would complement established conventional methods. This study aimed to characterize insecticide resistance in B. tabaci to cyantraniliprole (IRAC group 28) and imidacloprid (IRAC group 4a). The species was surveyed from 2020-2023 in Georgia farmscapes to provide toxicological statuses of the current field populations. Due to the unknown benefit of polyphagia for B. tabaci, several host plants were also investigated for their impact on insecticide response. Evaluations were focused on the adult life stage using a rapid systemic bioassay method. Results were based on the effectiveness of each insecticide on B. tabaci, with dose-response trends identified. Due to the potential benefit of control using hostplants, other control methods are also being pursued—mainly using entomopathogenic fungi and nematodes. Many biologicals, entomopathogenic fungi, and nematodes are naturally established organisms in whitefly-infested systems in Georgia. We aim to develop a management plan to improve their efficacy in field applications. Overall, these studies highlight the need to incorporate a multilayer approach to managing B. tabaci with the additional benefit of improved insecticide resistance management.