(2nd Place) Utilizing sweet alyssum flowers (Lobularia maritima) to enhance the biological control of the diamondback moth (Plutella xylostella) for sustainable Brassica production in the southeastern United States

Diamondback moth (DBM), Plutella xylostella, is a ubiquitous pest of Brassicaceae crops, leading to a global economic burden of $ 4-5 billion annually (yield losses + control costs). Over the past few decades, it has become a key pest of brassica crops due to resistance development against over 98 active insecticide ingredients, including novel diamide insecticides. Several natural enemies of DBM attack its larval and pupal stages and alone can suppress DBM populations through high parasitism rates ( >80%). However, grower reliance on insecticides eliminates beneficial natural enemies and drives the development of insecticide resistance. Sustainable biocontrol tactics, such as enhancing conservation biological control, could bring promising results if strategically introduced. We aim to investigate the potential of sweet alyssum flowers in suppressing DBM populations in small brassica fields with four treatment groups having four replicates arranged in a randomized complete block design (RCBD): 1) collards with interspersed alyssum, 2) collards with interspersed alyssum and foliar sprays of Bacillus thuringiensis (Bt), 3) collards treated with broad-spectrum pyrethroid sprays, and 4) untreated control group. A weekly sampling of DBM larvae, DBM pupae, and parasitoid pupae will be carried out to evaluate the DBM parasitism and predation rate. Three harvests will be conducted to evaluate which treatment provides the maximum marketable yield. Strategically incorporating sweet alyssum flowers in the brassica fields could formulate an efficient, economical biocontrol program to reduce DBM pest problems, consequently decreasing the reliance on broad-spectrum pesticides and increasing farmers’ profitability in the southeastern United States.