Peach leaf curl is a common disease caused by the fungus Taphrina deformans. Besides peaches, susceptible plants include nectarines and almonds.
The peach leaf curl fungus spends the winter in the bark and buds of its hosts. It enters new buds as they begin to swell and open in the spring, spread by rain and dew. Not surprisingly, wet weather creates a situation ripe for trouble with this disease.
Symptoms
- Pale or pinkish new leaves, depending on tree variety.
- Thick, puckered, curled leaves or portions of leaves.
- Leaf drop.
- Stunted twigs.
- Poor fruit yield.
- Raised, discolored spots with no fuzz on fruit.
- Gradual tree death.
Treatment
Trees that are showing symptoms of peach leaf curl cannot be treated until the following spring. In the meantime, thin the fruit and keep the tree healthy with adequate water and fertilizer.
Early in the spring, after the tree has been pruned but before the buds begin to swell, spray the tree thoroughly with the appropriate fungicide (organic growers can use copper). Make sure you cover the entire tree on all sides, from the trunk to every small twig. Be prepared to repeat the treatment if it rains. This process will probably need to be repeated in future years.
Prevention
The best prevention is to purchase fruit tree varieties resistant to peach leaf curl. Still, susceptibility can be reduced with attention to water and fertilizer. A good rule of thumb is to measure a shoot to see how much the tree grew the previous year. If the shoot is a foot long or shorter, fertilize the tree. Do not overdo, however, as excess growth tends to be soft and disease-prone.
Helpful Resource
Leaf Curl of Peaches and Nectarines
Brief factsheet useful for identifying the disease and understanding its life cycle.
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