POP TIPS: peach leaf curl alert!

[Phil Forsyth]

Philly Orchardists,

We've noticed our first signs of peach leaf curl on trees this past week.  This disease is very common in our humid climate, affecting most peaches in the city each year, and is very easy to diagnose!  See our POP TIPS on managing this common disease below. 

POP TIPS: Peach Leaf Curl

We're seeing a lot of signs peach leaf curl on trees around the city again this spring.  This is a fungal disease (Taphrina deformans) that causes leaves on peaches and nectarines to pucker and curl, turning from reddish to yellow to gray and then falling off.  It can sometimes also cause some disfigurement and drop of fruit, but this is less common.  

Good news is that Peach Leaf Curl will not kill your tree, nor does it usually directly affect most fruit.  However, bad infections can cause a loss of photosynthesis, resulting in additional stress on the tree, limiting yields and making trees more vulnerable to other pests and disease.    

Typical peach leaf curl damage above. 

Although not as common, peach leaf curl can also sometimes damage fruit, with mottling and cracking damage shown above. 

PEACH LEAF CURL MANAGEMENT

As with most tree diseases, it's too late for preventive measures by the time you see it.  At this point in the spring, Rodale's Handbook of Natural Insect and Disease Control suggests removing all the infected leaves to reduce the future source of re-infection.  These should be bagged up or added to a hot compost pile.  At this stage in the season, trees will send out new leaves to replace those removed. The impact of removing infected leaves in this way is not clear, it may or may not be effective in reducing the disease next season!  

Given that peach leaf curl stresses the tree through reduced photosynthesis, we strongly advise thinning your peach fruitlets to the recommended 8" apart on the tree to reduce additional stress.  This should be done between now and early June. Be sure to remove the fruitlets showing signs of infection! 

The only proven means of management is a copper or sulfur fungicide spray, applied in fall after leaf drop and/or in spring before bud break.  If you have a tree that is severely affected with the majority of leaves showing the disease, you may need to consider one of these organic sprays this fall and/or next spring.  Improving the overall health and resilience of trees through foliar applications of compost tea, neem oil, and other holistic sprays can also help reduce the rate of infection. 

For more info on peach leaf curl: 

http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7426.html

Phil Forsyth, Co-Executive Director

Philadelphia Orchard Project

www.phillyorchards.org

215-724-1247

Pronouns: he/him

"65 community orchards, 1472 fruit trees, and growing!"