Erythmelus klopomor : first steps toward classical biological control of the oak lace bug Corythucha arcuata , a potentially significant invader in the European oak forests

The North American Corythucha arcuata (Say, 1832) (Hemiptera: Tingidae), is a potentially significant invasive pest of European oaks (Quercus spp., Fagaceae). First detected in Europe in 2000 it currently occurs in 26 countries in the Palearctic region. Most Eurasian deciduous oaks are suitable host plants; about 30 million hectares of oak dominated forests in Europe can facilitate its spread. It has diverse negative effects on the invaded ecosystems. One main reason for its rapid expansion is the lack of a control agent. The only feasible control option is a classical biological control program. To study its parasitoids, we collected its eggs in six states of the USA in 2023–2024. 23.7% of our samples contained parasitoids, the average parasitism was 14.5%. So far results indicate that Erythmelus klopomor Triapitsyn 2007 (Hymenoptera: Mymaridae) is mainly parasitoid of Corythucha spp., with C. arcuata being its preferred host. Our conclusion is that E. klopomor is a promising and the only candidate for classical biological control, but further research efforts are unavoidable prior to a potential deliberate introduction to Europe.