High invertebrate biodiversity in willow short rotation coppice can be protected when controlling chrysomelid pests by using a spatially targeted insecticide application.

Abstract

Increasing farmland biodiversity is a major environmental benefit of growing willow short rotation coppice (SRC) on arable land. Biodoversity in SRC is high compared to other row crops primarily because of the abundant and diverse herbivorous, predatory and parasitic invertebrate community that lives in the willow canopy. However, this community usually includes several chrysomelid beetle species, one or more of which can become a pest through excessive defoliation. These beetles colonise the crop canopy from the edge each year and could be reached using an insecticide application applied from the field headland before they move into the whole field. This paper documents the effect of such an application experimentally on the target and non-target invertebrates. The results show that the technique can be effective against this pest and will have a relatively small effect on overall invertebrate populations and hence arguably, an acceptable cost to biodiversity.