How to Manage Pests
UC Pest Management Guidelines
Pathogen: Eutypa lata
(Reviewed 11/07, updated 2/09)
Eutypa dieback, also known as Cytosporina, gummosis, and limb dieback, causes limbs or twigs to wilt and die suddenly in late spring or summer with the leaves still attached. The bark has a dark discoloration with amber-colored gumming; infected areas in the interior of the wood are discolored brown.
This fungus infects fresh pruning wounds when rainfall occurs 2 to 6 weeks after pruning. While infections can occur at any time of the year during rainy periods, the greatest incidence is in fall and winter.
Remove infected limbs at least 1 foot below any internal symptom of the disease. The preferred control method is to prune during July and August after harvest. There is less regrowth from pruning cuts if pruning is done in August. Ideally, pruning should be completed at least 6 weeks before the first fall rains. Wound treatments with paints or sealants have not been satisfactory because of lack of efficacy or difficulty in treating all of the pruning wounds immediately after being made. If pruning wounds are made outside of the preferred pruning period of July/August, use a fungicide to treat the wounds.
UC IPM Pest Management Guidelines:
J. E. Adaskaveg, Plant Pathology, UC Riverside