Enhancing the efficacy of entomopathogenic nematodes for improved biological control

The biological control of plant pests is a natural occurrence that can be adapted and enhanced to mitigate damage to cultivated crops. The use of entomopathogenic nematodes (EPNs) in this manner is common in many integrated pest management (IPM) programs that target insect pests with a soil-dwelling life stage. EPNs are virulent against a large host range, which increases their chances of being used as an IPM tool, even in areas outside their natural biomes. To ensure consistent efficacy once applied, EPNs can be paired with efficacy boosters that enhance their ecological roles as microbial biological control agents. The objectives of these studies were to evaluate the impact of ascarosides (EPN-relevant biological products) on the efficacy of EPNs applied for pest management. EPNs exposed to ascaroside extracts had enhanced efficacy against two economically important pests in two different systems, the pecan weevil Curculio caryae (soil application) and the whitefly Bemisia tabaci (foliar application). Soil application of pheromone exposed EPNs resulted in an additional 25% decrease in C. caryae compared to non-treated EPNs. Foliar application of pheromone-exposed EPNs resulted in B. tabaci adult mortality up to 80% and reduced nymph survival down to 6% with the addition of a gel adjuvant. These studies are the first to highlight the impact of EPN-pheromone combinations in the field (C. caryae) and foliar applications (B. tabaci). With increased efficacy, the use of EPNs reduces reliance on synthetic management methods and highlights a potential new avenue for EPN use in IPM programs.