LC50 responses of Bemisia tabaci (Hemiptera: Aleyrodidae) adult populations to imidacloprid in Georgia, USA

Authors: PERIER, JERMAINE - University Of Georgia; CREMONEZ, PAULO - University Of Georgia; SMITH, HUGH - University Of Florida; Simmons, Alvin; RILEY, DAVID - University Of Florida

Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/14/2023
Publication Date: 3/22/2024
Citation: Perier, J.D., Cremonez, P.S., Smith, H.A., Simmons, A.M., Riley, D.G. 2024. LC50 responses of Bemisia tabaci (Hemiptera: Aleyrodidae) adult populations to imidacloprid in Georgia, USA. Journal of Entomological Science. 59(2):182-192. https://doi.org/10.18474/JES23-41.
DOI: https://doi.org/10.18474/JES23-41

Interpretive Summary: Imidacloprid is an insecticide that is commonly used to manage sucking pests like whiteflies. Because resistance to insecticides can develop when insecticides are used over and over again, a study was conducted to assess the level of resistance to imidacloprid that exists in populations of the sweetpotato whitefly in fields in Georgia. The dose of imidacloprid needed to kill whiteflies was assessed in several counties in southern Georgia where most economic losses occur. The study demonstrated that the resistance of insecticide to imidacloprid varies for whiteflies across different counties in Georgia, but the insects has less resistance than as compared to a reference population of whiteflies in Florida. This baseline information will be useful to the scientific and agricultural communities in the development of insecticide resistance management programs for whiteflies and other insect pests of crops.

Technical Abstract: Imidacloprid has been one of the most widely used insecticides for whitefly, Bemisia tabaci, control in the USA since the EPA first registered it in 1994. This has led to many cases of documented resistance development and major control failures, especially in Georgia, USA, where annual B. tabaci induced economic losses surpassed USD ~160 million in 2017. Vegetable and cotton production in the state are at substantial risk of B. tabaci infestation and are subjected to repetitive insecticide programs to preserve yield. No previous extensive survey for imidacloprid dose response in whitefly exists for the state of Georgia, just a single site documentation of imidacloprid resistance in adults in 2007. Therefore, several counties in southern Georgia where most economic losses occurred were surveyed and subjected to an adult mortality bioassay of a range of imidacloprid concentrations. This included a maximum dose concentration representing the current highest labeled rate. Dose response to the insecticide was not uniform across locations as hypothesized, with several locations surprisingly displaying susceptibility to imidacloprid. LC50s ranging from 0.02 – 196.05 mg a.i. L1 in Georgia whitefly populations was substantially lower than the reference Florida whitefly population. This baseline information for the state is critical to future evaluations of this insecticide in insecticide resistance management programs.