Nectria infection of beech bark in relation to infestation by Cryptococcus fagisuga Lindiger

Wound inoculation with an isolate of Nectria coccinea produced cankers in beech bark, the size of which was related to the severity of C. fagisuga infestation. Lesions were absent in most cases following surface inoculation of bark (non wounding) with very localised but heavy infestation. Inhibition of the host's response to fungal invasion is considered to be an important part of the insect's role in producing beech bark disease.