The distribution and frequency of vascular lesions due to infection by Leptosphaeria coniothyriu m was recorded in primocanes from mechanically harvested plots of four red raspberry cultivars which received fungicide sprays after each of four harvests.
The catching-plates wounded the same number of canes in both stooled and hedgerow plots but more were wounded in the latter, where there were more canes, by the vibrating-fingers. The same percentage of damaged canes became infected in both types of plots. In all cultivars the fingers also wounded a higher percentage of canes than did the plates. Although infection occurred more readily at catching-plate wounds more canes per plot were infected at finger wounds.
Dichlofluanid and thiophanate-methyl substantially reduced the incidence of vascular lesions arising from both types of wounds. The overall control of L. coniothyrium was better in cv. Malling Jewel and cv. Glen Isla than in cv. Malling M and cv. Glen Clova.