{"id":4609,"date":"2011-03-18T15:37:06","date_gmt":"2011-03-18T19:37:06","guid":{"rendered":"http:\/\/extension.umaine.edu\/ipm\/"},"modified":"2021-08-31T16:15:16","modified_gmt":"2021-08-31T20:15:16","slug":"5098e","status":"publish","type":"page","link":"https:\/\/extension.umaine.edu\/ipm\/ipddl\/publications\/5098e\/","title":{"rendered":"Peach Leaf Curl"},"content":{"rendered":"

\n \n \"Print\n <\/a>\n <\/div><\/h3>\n

Pest Management Fact Sheet #5098<\/h3>\n

Authors: Dr. Alicyn Smart, Dr. Bruce Watt, and Abigayl Novak<\/em><\/p>\n

For information about UMaine Extension programs and resources, visit extension.umaine.edu<\/a>.
\nFind more of our publications and books at extension.umaine.edu\/publications\/<\/a>.<\/strong>
\n<\/span><\/strong><\/p>\n

Other Name:<\/strong> Leaf curl
\n<\/em>Pathogen:<\/strong>\u00a0Taphrina deformans<\/em><\/h4>\n

Introduction<\/h3>\n
\"Microscopic<\/a>
Figure 1. Ascus with ascospores. Photo by Dr. Bruce Watt.<\/figcaption><\/figure>\n

Peach leaf curl is caused by the fungus Taphrina deformans<\/em>. It occurs commonly in Maine on both nectarines and peaches. Although this fungus can infect the fruit, most losses are due to reduced vigor caused by defoliation. Subsequent refoliation uses energy reserves which would otherwise be used to produce fruit. The weakened trees are also more susceptible to winter injury. When the fruit is infected, it is likely to drop before maturity.<\/p>\n

Spores that form on the surface of the leaf are the overwintering stage of the fungus. These spores are dispersed by the wind and splashing rain. They land in the cracks and crevices of the tree and in the bud scales where they rest until the following season. In the spring, spore germination is timed to coincide with the emergence of the leaf tissue. These initial spores (ascospores) germinate to produce another spore type (blastospores) which reproduce by budding. The spores fall onto susceptible tissues and germinate to penetrate the tissue directly.<\/p>\n

As with most fungi, free water is very important to the infection process. Wet weather during bud-break and leaf emergence is favorable to the disease. Infections can begin at temperatures below 50\u00b0F, slowly.<\/p>\n

Host Plants<\/h3>\n
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  • Peach and nectarine (Prunus persica<\/em>), and cherries (Prunus<\/em>), occasionally almond (Prunus dulci)<\/em> and apricot (Prunus<\/em>)<\/li>\n<\/ul>\n

    Symptoms and Signs<\/h3>\n

    As the name implies, the disease is expressed as distorted or curled leaf tissue. These puckered, thickened leaves often have a characteristic reddish-purple color where the distortions occur (Figure 2 and 3). These symptoms may begin early in the season as the leaves are unfolding. Later the color turns to a powdery gray on the upper leaf surface as the fungus begins to produce spores. As the season progresses and the weather turns warmer and drier, the leaves turn yellow, brown, and finally defoliate.<\/p>\n\n\t\t