Field-plot tests were carried out in Scotland in 1976-77 on interactions between the time of cane removal of Glen Clova, a highly vigorous cultivar of red raspberry, infestations with the cecidomyiid Resseliella theobaldi (Barnes), and the occurrence of some cane diseases. The first flush of young canes was removed at different dates in spring by applying the contact herbicide dinoseb. Comparison with untreated plots showed that cane removal increased fruit yield, controlled excessive cane vigour and improved the health status of vegetative canes in a plantation infested with the midge. At the end of the growing season, vegetative canes in treated plots were shorter and thinner, and sustained less physical injury than those in untreated plots. Access to the fruit at harvest was also improved. Reduced competition between fruiting and vegetative canes increased yield in the year of treatment by an average of 35%. Yield was not affected by the date of cane removal, but growth of replacement cane was reduced below an optimum level when first flush cane was removed after mid-May.The incidence of pests and diseases became less as the time the canes were removed became later. Cankers and lobate vascular lesions ('patches') resulting from feeding by first- and second-generation larvae (with associated fungi), respectively, affected fewer canes in treated plots than in untreated ones. Significantly fewer live larvae were recovered in the following winter from soil in plots treated on or after 11 May than from that in untreated plots. The main effect of vigour control on R. theobaldi and midge blight was that replacement canes provided fewer egg-laying sites (natural splits) than did the first flush canes in untreated plots. The incidence of spreading vascular lesions ('stripes') attributed to Leptosphaeria coniothyrium infecting either physical wounds (cane blight) or midge feeding wounds (midge blight) was substantially less in treated plots than in untreated ones. Cane botrytis (Botrytis cinerea) and spur blight (Didymella applanata) were also less common in treated plots. Interactions between vigour control and pest and disease incidence are discussed in relation to the efficient management of the cultivar in eastern Scotland.