Longevity of the whitefly parasitoid Eretmocerus eremicus under two different climate scenarios

Whiteflies (Aleyrodidae) cause high economic losses in agricultural systems worldwide. Heavy reliance on insecticide use for whitefly control has led to the resistance development towards nearly all used groups of insecticides. A more sustainable, widely used, and irreplaceable control measure in protected cropping systems is biological control by augmentative release of parasitoids. All commercially available whitefly parasitoids are wasps from the genera Encarsia and Eretmocerus, with one of the most used parasitoid species being Eretmocerus eremicus. Biocontrol by these highly specialized natural enemies is sensitive to changes in environmental conditions. Ongoing anthropogenic climate change could affect multitrophic interactions between organisms, and biocontrol systems are not an exception. At the same time, little is known about the development of E. eremicus under projected future climate conditions. The present study evaluates the longevity of this important biocontrol agent by performing climatic chamber simulation driven by physically consistent, regionally downscaled, multi-model ensemble projections of the future climate for Luxembourg. Results show a reduction of its longevity up to 50% under future climate. The median survival in the projected future climate was found to be 13 days, which is 9 days less than under present climate. Implications on the efficacy of the whitefly biocontrol practices in future climate conditions are discussed.