When raspberries and thornless blackberries have new growth often the top 2-3cm starts to brown off and die. Sometimes when I have nipped the dying piece off I have found a little caterpillar inside. Can you help?
Burrowing caterpillars in the stems of raspberry and blackberry plants are a frequent problem and unfortunately not the easiest to deal with.
Winter pruning should involve removing all old canes from the bushes - either burn or remove them from your property. Check this season’s canes (next season’s fruiting canes) to ensure there are no burrowing caterpillars.
Symptoms will be dead leaves and you will need to cut the canes and inspect the insides to see if any caterpillar infection is present. They should be easily identifiable. If they are still apparent, we suggest removing the entire plant and starting again with some newly purchased specimens. While it is possible to spray with systemic insecticides; with plants that produce edible fruit or berries, spraying may not be a viable option.