The biology, damage and control of the poplar and willow borer,Cryptorrhynchus lapathi

Abstract

Cryptorrhynchus lapathi has a two-year life cycle, during which it hibernates once as a first instar larva, and again as an adult. As a rule the adults emerge, feed and lay eggs in the even years, while the larvae have their main feeding period in the odd years. The species is harmful to poplar and willow, not only by its own feeding, but also indirectly by facilitating entrance of other insects and infection by micro-organisms. Control by insecticides should preferably not take place in the adult, but in the larval stage. In both cases very poisonous chemicals are required, but the amounts needed for controlling the larvae are smaller than those needed to control the adults and the techniques for applying them entail less risk of poisoning other organisms.