This article appeared in the March 2002 issue of Horticulture Update,
edited by Dr. William C. Welch, and produced by Extension Horticulture,
Texas Cooperative Extension, The Texas A&M University System, College Station, Texas.

Peach Leaf Curl

By Cynthia W. Mueller, Master Gardener
Galveston County, Texas

Click on picture to see larger image he accompanying image, taken in late February in the peach seedling plantings near the Horticulture Building on the Texas A&M campus, illustrates an outbreak of the disease known as Peach Leaf Curl.

At first glance, the disease resembles glossy, bright green insect galls with tints of red dotted over the peach leaves, but is actually a fungus that infects leaves, flowers and fruits. The affected leaves begin to pucker, curl and thicken, usually becoming light green to pale yellow in color, and are finally shed. The pathogen is Taphrina deformans, a close relative of the Taphrina species that causes oak leaf blister disease. According to Dr. Larry Barnes of the Plant Pathology Department at Texas A&M University, Taphrina deformans overwinters in the bud scales, and infects newly emerging leaves, blossoms and fruit. The blossoms and fruit soon drop after infection by the fungus, and may not be noticed by the grower. By the time leaves are fully expanded, they will no longer be susceptible to the fungus.

The likelihood of disease development is related to optimum conditions of air temperature at the time of bud opening, combined with good surface moisture conditions. Air temperature above 86 degrees F. and below 40 degrees F. inhibit growth of the fungus. Dr. Barnes says that control measures are usually not needed. Because it is not possible to control the outbreak after symptoms are visible, the best preventive technique would be to apply a fungicide such as Daconil at the beginning of dormancy and/or just prior to bud break.