Abstract

Two types of vascular lesion are described from the base of raspberry canes infested by larvae of Resseliella theobaldi (Barnes) in Scottish plantations; these were called patches, which were brown lobate lesions confined to midge feeding areas, and stripes, which were brown lesions spreading proximally and distally from the point of infection. Either or both types of lesion could be present in individual canes. Isolations from patches produced principally Fusarium avenaceum, those from tissues where patches and stripes were contiguous gave Leptosphaeria coniothyrium and F. avenaceum, and those from stripes arising from old cane stub wounds in the absence of the midge gave L. coniothyrium. The important secondary role of fungi in the midge blight complex is confirmed, but the involvement of L. coniothyrium in the complex is unclear because it also infects stub wounds on midge-infested canes.