Most pesticide treatments on bramble (caneberry) crops can be made on an "as needed" basis (Table 16). However, this approach requires regular inspection trips so that needed applications can be made before serious damage occurs. In addition, a good sanitation program in and around the planting will help alleviate a number of common pest problems.
Cultural Practices for Disease and Insect Control
Always plant in a well-drained location with all-day sun (no shade). Raspberry and blackberry plantings established on wet sites are doomed to failure.
Most fungi that infect raspberry and blackberry canes overwinter on old canes that were infected the previous season. After harvest, cut and remove from the planting canes that have fruited (except for Heritage or other fall fruiting red raspberry cultivars) to reduce the incidence of spur blight, cane blight and anthracnose, as well as populations of cane and crown borer insects. Mow or cut old Heritage canes in the early spring before new shoots begin to develop. Cuts should be made at ground level (no stubs), and all old canes should be removed from the planting.
Good weed control promotes rapid drying conditions within the fruiting canopy and discourages populations of insects and diseases that damage the canes and fruit. In order to promote better penetration of sunlight and faster drying within the canopy of red raspberries, canes should be thinned (removed) to obtain no more than five large canes per linear foot of row, and row width should not exceed two feet.
Each spring when new shoots are about 12 to 14 inches tall, survey black raspberry and blackberry plantings for symptoms of orange rust and viruses. Orange rust, a destructive disease of black raspberry and blackberry, can be controlled only by removing all infected plants (including their roots) when symptoms first appear. Infected shoots are identified by their thin, willowy growth, the absence of thorns (on normally thorny varieties) and the presence of orange spore pustules on the underside of leaves. Failure to remove orange rust-infected plants threatens the survival of healthy plants.
Problems with sap beetles, wasps, fruit flies and fruit rots will be less severe if the berries are harvested regularly throughout the ripening period so that overripe fruits do not accumulate. Fermenting fruit attracts these pests.
Japanese beetles feed on ripe raspberry and blackberry fruit, as well as leaves. Remove beetles by hand as much as possible and destroy them.