D3113: Integrated pest management of chilli thrips in Alabama nurseries

Chilli thrips (Scirtothrips dorsalis Hood) are economically important pests of ornamental, fruit, and vegetable production. In ornamental crop systems, this species causes significant damage resulting in drastic reduction in plant marketability. While chilli thrips are found worldwide, their establishment in Florida (1991) and Alabama (2017) have only recently been documented. Furthermore, resistance to insecticides have been observed within their native range and the Southeastern United States. Due to this rapid range expansion and documented resistance, exploring population dynamics and alternative management strategies have become a necessity. This study aims to investigate biological control strategies, potential volatile attractants, insecticide resistance, and seasonal flight patterns/abundance of chilli thrips within Alabama. In a two-year study conducted in Mobile, Alabama, sticky cards were collected from plant nurseries to determine abundance and seasonal distribution. Populations of chilli thrips were most abundant in 3-month periods during the spring and fall of each year, with peak populations being observed in April and October. A biocontrol assay is currently underway to determine the efficacy of two predatory species (minute pirate bugs and Amblyseius swirskii mites) in controlling chilli thrips populations. This assay will include host plants of distylium, cleyera, rose, and azalea with heavy chilli thrips populations and damage in Auburn and Mobile. These results may indicate that shifting away from frequent chemical control applications could mitigate further development of insecticide resistance in these areas. Future studies regarding chilli thrips attractants via pruning induced plant volatiles and an insecticide resistance determining bioassay will also be discussed.