Occurrence, performance and shoot damage of <i>Tomicus piniperda</i> in pine stands in southern Sweden after storm‐felling

Abstract

Abstract The pine shoot beetle, Tomicus piniperda (L.), is considered one of the most destructive pests of Scots pine, Pinus sylvestris (L.), in Europe. At high population densities, its feeding in the shoots of living pine trees may lead to substantial shoot and subsequent growth losses. After a storm‐felling in southern Sweden in January 2005, there were high amounts of breeding material and a subsequent risk for bark beetle outbreaks. To study the beetle's reproductive success, population levels and risks for growth losses, we analysed bark samples of colonized trees, and counted fallen pine shoots. During the first season after the storm‐felling, the pine shoot beetle population level was low. However, due to high reproductive success beetle numbers markedly increased in the second season, and there were high rates of successful colonization of available host material in following years. Shoot damage levels concomitantly rose in 2005–2006, then declined in 2007 and 2008. However, the accumulated shoot losses do not indicate any subsequent growth losses, as the recorded shoot damage levels were below those earlier seen in connection with growth reductions in damaged pine stands.