Fruit IPM Fact Sheet

Peach Leaf Curl

By: Mark Longstroth

District Extension Horticultural and Marketing Educato

 

Peach leaf curl is an infrequent but occasionally severe disease of peach and nectarine. The disease does not attack other fruit trees such as apples and cherries. A similar disease does attack plums.

The pathogen infects peach buds from bud swell to bud opening under wet conditions and air temperatures in the 50^o to 70^oF range. Infections can take place in the spring from bud swell to bud opening. By the time symptoms are seen, the treatment window has passed. If you have this disease you need to treat in the Fall or early Spring before bud break.

Bravo (chlorothalonil), Ferbam (Carbamate), Ziram, and copper compounds are all effective against this disease.  Copper compounds have the benefit of providing some suppression of bacterial spot as well. Bravo is rumored to help suppress Cytospora canker. But, there is no data to support this.

The key to good disease control is early spring applications of materials that suppress fungal growth as the bud opens. These sprays need to be made before rain washs the overwintering spores into the bud. Good coverage is needed to control this disease. You can take advantage of fall applications to get the job done when the pace is less hectic.  In extreme situations, I have recommended both spring and fall applications.

Once leaves are infected in the spring there is no treatment The leaves are infected in the bud and once they have emerged they are not suseptable to infection. Leaves will become thick and crinkled, turning orange or red. When the fungus sporulates the leaves will become powdery.

The leaves will eventually fall off and the tree will grow new ones. Peach leaf curl will only weaken the tree by removing leaves. This may also cause fruit drop and reduce the size of the remaining fruit.

After infection little can be done.  I usually recommend increased nitrogen to decrease the stress on the tree. This allows the tree to resume growth and replace the infected leaves more quickly.  We are seeing more and more peach leaf curl as new systemic fungicide materials replace our older protectants.   I think the new materials are less effective on peach leaf curl spores so we have more overwintering spores.

 

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Created: June 4, 1997
Last modified: February 26, 2005