Prune out Raspberry Pest Problems
Put away the chemicals and break out the pruners to control pest problems on raspberries.
Dry crumbly fruit, spotted and discolored stems, as well as spotted, brown and yellow leaves are symptoms of anthracnose and spur blight diseases.
Proper placement, spacing and care are usually enough to keep the plants healthy and minimize the risk of these diseases.
Grow plants at the proper spacing in full sun for the best productivity and fewer disease problems. Prune consistently to increase airflow and light penetration to further reduce the risk of these and other diseases.
Remove and destroy diseased canes as soon as they are found. Prune out the canes that bore fruit in summer. Removing these to ground level soon after harvest further reduces the risk of disease.
Thin the remaining canes to 4 to 5 canes per foot in late winter or early spring.
A bit more information: The fall crop on fall or everbearing raspberries forms on new stems that sprouted in the spring. You can prune all the canes to the ground when the plants are dormant. This eliminates the summer crop, but will give you a larger and earlier fall harvest. If you want both a summer and fall harvest then follow pruning guidelines for the summer-bearing raspberries.