The distribution of Phratora vulgatissima (Coleoptera: Chrysomelidae) on cultivated willows in Britain and Ireland.

Abstract

Insect samples were collected from the canopy of 24 willow short rotation coppice (SRC) sites on farmland in Britain and Ireland in 1995. The blue willow beetle Phratora (=Phyllodecta) vulgatissima (L.) (Coleoptera: Chrysomelidae), previously identified as the main defoliating pest of this crop, was recorded from 13 of these at varying levels of abundance. Data describing aspects of the environment at each site were also collected. These data were used to create potential explanatory variables for a regression analysis of beetle abundance. This analysis indicated that P. vulgatissima were most likely to occur and were more abundant at older willow sites on clay soils and at sites that had certain free-living willow species growing nearby. Within sites, most willow clones sampled contained P. vulgatissima, although two, Salix burjatica 'Germany' (,Aquatica Gigantea') and Salix mollissima 'Q83' (Salix triandra x Salix viminalis), were avoided. Chrysomelid pest avoidance and clonal resistance could form part of an integrated pest management strategy for SRC crops.