Selection responses and quantitative-genetic analysis of preadult performance on two host plants in the bean weevil, Acanthoscelides obtectus

The infectivity and biocontrol potential of entomopathogenic nematodes against two common urban tree leaf beetles (Altica quercetorum and Agelastica alni) pupating in the soil were examined under laboratory and semi‐field conditions. In the laboratory experiments, pre‐pupae and pupae of both insect species were shown to be highly susceptible to nematode infection when challenged in soil pre‐treated with the parasites’ infective juveniles. In general, Heterorhabditis megidis was more effective than Steinernema feltiae. However, significant differences were observed between individual isolates within the latter species. Nematodes developed and reproduced in cadavers of both insect species. A semi‐field experiment studying the biocontrol potential of selected nematode strains, conducted under the canopy of urban trees, confirmed the preliminary laboratory findings and revealed that H. megidis could eliminate most of the insects pupating in the soil, when applied at a relatively low dose of 10⁵ IJs m^?2. The potential of entomopathogenic nematodes as environmentally safe, effective, and economically viable agents for the biological control of tree leaf beetles in urban green areas is discussed.