Comparison of two release strategies for the American hoverfly, Eupeodes americanus , against the green peach aphid in greenhouses: Banker plant vs. pupal release

Predatory hoverflies can provide dual ecosystem services since adults are pollinators and larvae are aphidophagous biocontrol agents. In the present study, we compare the effects of two release strategies, banker plant and pupal release on the potential of the American hoverfly, Eupeodes americanus to control Myzus persicae and to improve pollination of sweet pepper (Capsicum annuum) in research greenhouses. Results show that E. americanus effectively controls aphids regardless of the release strategy with an infestation reduction ranging from 91 to 99% depending on the year. However, the production of new adult hoverflies over time without needing additional releases is an advantage of the banker plant strategy. Indeed, adults' number were multiplied by 7 throughout the duration of the experiment, i.e., 8 weeks while the pupal release strategy had a constant number of adults with no increase. Finally, the use of E. americanus significantly increased the fruit yield by 88.4% and 97.5% respectively for banker plant and pupae release treatments compared to the control. However, further studies are necessary to confirm its impact on pollination of sweet pepper plant since a greater occurrence of malformation in fruit occurred in both hoverfly treatments. In conclusion, the present study is the first to clearly demonstrate that E. americanus is an efficient predator against M. persicae via banker plant or pupal release. It also reveals its potential as a pollinator, another key ecosystem service in agricultural production.