|I planted red raspberry bushes last year. This spring they appeared healthy, now the tips of the leaves on some of the canes turn brown, then the leaf edges do likewise and finally the whole leaf browns and curls up and eventually the cane dies. I do not see any bugs on them, Our extension agent suspected cane borer and suggested we spray. I don't see any improvememt. Also I do not note any swelling of the cane as you suggested would be seen in a response to someone else's question. Ideas??|
|Have the plants been receiving adequate water? If you have had a very dry spring and early summer, as we have had up in the north, then your plants could simply be suffering from drought, especially since they are quite young. On the other hand, if they are sitting in saturated soil, that could cause similar symptoms.
If you are sure water isn't a problem, then I would examine the leaves carefully. Look for spots, powdery patches, bright orange dots, or fine webbing. These signs would help us identify the culprit. Also look for small holes near the base of the cane--evidence of a borer infestation. Keep the plants pruned so they get good air circulation; this can help reduce disease problems.
If only some of the canes are affected, I would prune these back right to the ground and destroy them. That way, whether it is a borer or a disease, you'll be removing at least some of the culprits.
I hope this helps.