Screening for predators of Aphis nerii and Myzus persicae on Mandevilla

Mandevilla (=Dipladenia) plants (Apocynaceae) are increasing in popularity in the greenhouse ornamental plant industry. These plants produce toxic cardenolides that, through the food chain, can affect natural enemies compromising biological control strategies. We conducted experiments to iden�fy promising natural enemies able to suppress popula�ons of two main aphid pests of Mandevilla: Aphis nerii (Boyer de Fonscolombe) and Myzus persicae (Sulzer). We tested four aphid predator species in semi-field condi�ons to evaluate their poten�al to control aphid popula�ons. Micromus variegatus (Fabricius) and Propylea quatordecimpunctata (Linnaeus) reduced both aphid popula�ons compared to the control. Scymnus interruptus (Goeze) showed contradictory results between A. nerii and M. persicae. Aphidoletes aphidimyza (Rondani) didn’t show an effect on pest suppression. In addi�on, a laboratory experiment was carried out to clarify the effects of prey on the brown lacewings Micromus variegatus. On Mandevilla, a lower fecundity of M. variegatus females was observed on A. nerii than on M. persicae. These effects can be related to A. nerii’s ability to sequester toxic cardenolide produced by Mandevilla. Information obtained here will be used for future research on biological control strategies in this ornamental plant.