ABSTRACT
Similarly, other bark beetles and wood wasps are vectors of other fungal pathogens of trees. Redfern (1989) discussed the role of the bark beetle Ips cembrae in transmitting the fungal disease Ceratocystis lariciola and the wasp Urocerus gigas in transmitting Amylostereum chailletii, both of which cause dieback and death of larches. The degree of damage to the tree by fungal pathogens introduced by both the bark beetle and the wood wasp appears to be density-dependent. Where the population of the insects is high and causes severe attack of the tree, tree death is a likely outcome. Where insect density is low, the effect of the fungus is relatively minor (Fig. 4.12).
