The Lacewings Micromus angulatus and Chrysoperla carnea as Predators of the Rhododendron Aphid, Illinoia lambersi, Under Different Temperature Regimes

Illinoia lambersi is a key aphid pest in Rhododendron cultivation in northwestern Europe, where control measures still heavily rely on chemical insecticides. The present laboratory study assessed the predatory potential of the brown lacewing Micromus angulatus on a mix of late instars and adults of I. lambersi across three temperatures (15, 20, and 25 °C) and compared its performance with that of the commonly used green lacewing Chrysoperla carnea sensu lato. Predation rates were measured for third-instar larvae and adults of M. angulatus and for second- and third-instar larvae of C. carnea. Third instars of M. angulatus were highly effective, killing 30–52 aphids per day, with predation significantly increasing at 25 °C. At 15 °C, M. angulatus third instars performed similarly to C. carnea third instars; at 20 °C, C. carnea exhibited higher predation. In all cases, M. angulatus third instars outperformed C. carnea second instars. Female M. angulatus adults maintained steady predation rates (≈30–40 aphids per day) across temperatures, whereas males were less voracious. These findings highlight the potential of M. angulatus as a predator in both its larval and adult stages for integration into IPM programs targeting in particular early-season I. lambersi outbreaks under cool spring conditions. Further field studies are needed to validate laboratory findings and assess the performance of the predator across different Rhododendron cultivars.