Spotlight on Eupeodes americanus: Oviposition and fertility under HPS- and full spectrum LED-extended photoperiod in northern greenhouses

Abstract

In northern temperate regions, high-pressure sodium vapor (HPS) or light-emitting diode (LED) lights for supplemental lighting in winter greenhouses are used to extend the photoperiod and increase plant production. These different greenhouse light treatments influence crop pests and their natural enemies. In this study, different greenhouse light treatments were evaluated for their effect on the green peach aphid, Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae) and its predator the American hoverfly, Eupeodes americanus (Wiedemann, 1830) (Diptera: Syrphidae). In particular, the development of M. persicae and the oviposition and egg hatchability of E. americanus were studied under three light treatments in winter greenhouse: 1) short photoperiod of natural sunlight, and extended photoperiod using either 2) full spectrum LED or 3) HPS lights. The results showed that both extended photoperiod treatments significantly increased M. persicae population growth by 103–130 %, after 12 days compared to short photoperiod of sunlight. Compared to the winter short photoperiod of sunlight, extending the photoperiod did not affect the oviposition of female hoverflies in terms of fecundity, fertility, and niche use (i.e., position of eggs on the plant). Nevertheless, extended photoperiod significantly increased the egg hatchability of E. americanus by 9 % (HPS) and 16 % (LED) compared to short photoperiod of sunlight. This treatment had the highest proportion of unhatched eggs (13 %). Finally, LED lights decreased the proportion of unhatched eggs by 71 % compared to HPS lights. This study, therefore, confirms the potential of the American hoverfly as a biological control agent in winter greenhouses, both with or without artificial light.