Description:
Pine weevils can damage or kill young conifers planted on clearfell sites by feeding on the bark of the main stem. Insecticides are commonly used to minimise damage. The ability of young trees to survive or resist attack can make a significant contribution to the management of this important pest. The degree of resistance depends on the size of resin ducts in the bark and the amount of resin that flows from them when they are damaged by weevil attack. On resistant trees, feeding is largely confined to the outer bark, which contains few resin ducts, so that damage to the cambium and the risk of the stem being girdled is reduced. Pine is generally more resistant than spruce, but in both, recognising the expression of resistance in young trees on restock sites can ensure that post-planting applications of insecticides are only made when and where necessary.