The brown lacewing Micromus angulatus as a biological control agent of the rhododendron aphid Illinoia lambersi

Abstract: Lacewings play a significant role as natural enemies of soft-bodied pests such as
aphids. Micromus angulatus, a brown lacewing, possesses some advantages over other
lacewing species due to its ability to prey on aphids throughout both its adult and larval stages and sustained voracity at lower temperatures. This adaptability makes M. angulatus especially well-suited for application in open-field production, including rhododendron culture, where the rhododendron aphid, Illinoia lambersi, poses a major threat. However, there is limited information regarding the predatory efficacy of M. angulatus, as well as the knowledge of biological control methods targeting I. lambersi. We conducted laboratory experiments at three constant temperatures (15 °C, 20 °C and 25 °C), to evaluate the effect of temperature on the predatory efficacy of larvae and adults of M. angulatus on I. lambersi. For both larvae and female adults we observed no difference in predation efficacy between 15 °C and 20 °C. However, predation efficacy was higher for larvae at 25 °C compared to 15 °C and 20 °C, while female adults only performed better at 25 °C compared to 15 °C. At 25 °C female adults had a higher predation efficacy than male adults. Our laboratory findings show that both adult and larval stages of M. angulatus effectively prey on I. lambersi at lower temperatures, like 15 ℃, and thus may contribute to the development of sustainable pest management strategies in open-field horticulture.