Black spots on leaves - Knowledgebase Question

Greensboro, No
Question by leighanntedr
May 9, 2010
I have black spots on my bartlett pear tree. Also, the trunk is damaged. I believe a deer is running it's antlers up and down the trunk, although I cannot seem to catch him. Please help.

Answer from NGA
May 9, 2010


Fabraea leaf spot, also known as leaf blight and black spot, is caused by the fungus Fabraea maculata. This disease usually appears late in the growing season but can occasionally develop in late May and early June. Fabraea leaf spot attacks leaves, fruit, and twigs of pear. Symptoms first appear as brown to black spots on the leaves. Heavily infected leaves often yellow and drop prematurely. Severe defoliation can substantially reduce tree vigor and yield, especially if trees are defoliated several years in a row. Lesions on fruit appear similar to those on leaves but become slightly sunken as fruit expand. Severely infected fruit may also crack. Once established in a tree or planting, this disease is difficult to control since significant amounts of fungal inoculum overwinter on infected leaves. Spores of the fungus are easily spread by splashing rain and wind in the spring.

Effective control includes a good sanitation program. Since overwintering infected leaves are a major source of spores in the spring, removal of all fallen leaves during the dormant season significantly reduces the chances for new infection. In addition, properly selected and timed fungicide sprays are important for disease control. Lime/sulfur or fixed copper are the fungicides of choice and repeat sprays will be required beginning at the green cluster bud stage - after the blossom buds are fully exposed but before they separate from the cluster, then again 7 days later. Follow the treatment guidelines on the fungicide label.

About the only way to protect your tree from deer is to place a barrier between the trunk and the deer. You can drive 3 metal stakes into the ground around the tree - about 18-24 inches away from the trunk and then attach chicken wire or hardware cloth to the stakes. The deer won't be able to make direct contact with the tree trunk. Good luck with your pear tree.

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