Peach Leaf Curl - Chaos!

Learning Library
Written By Dominic Gamache

Peach Leaf Curl – Chaos! 

Note:  Peach Leaf Curl is successfully treated with an application of a fungicide in fall with a repeat application in late winter just before the leaves emerge.  Treatment after the damage is observed will not have any impact.  This overview can serve as a guide for planning treatment in the future. 

Peach Leaf Curl is caused by the fungus Taphrina deformans and only infects peach and nectarine trees.  It affects the blossoms, fruit, leaves, and shoots and can be identified by the distorted, red and gnarled, scab-like growth that it causes. 

Spores are produced by the leaf curl fungus overwinter on the tree and buds, germinating in Spring.  The disease’s spores are spread by splashing rain, dew or irrigation.  Symptoms appear on new foliage approximately two weeks after leaves emerge. Untreated it can kill a tree within two to three years and severe infection will impact fruit production.     

Cultural Controls 

  • Plant varieties that are resistant or partially resistant to leaf curl.
    ~   We have ‘Frost’ peach (must receive fungicide applications for the first 2-3 years.

  • Thin the fruit in order to help conserve tree energy. 

  • Water weekly when the tree is in leaf. 

  • Fertilize with a high nitrogen, organic fertilizer in spring, avoiding summer and fall fertilization. 

  • Prune in fall to reduce the number of spores that overwinter, avoiding late summer or early fall pruning. 

  • Clean and keep debris cleared beneath the tree, especially during winter. Do not put infected plant material in your home compost bin or pile. 

Biological Controls:  There is no proven biological control for peach leaf curl. 

Chemical Controls:  Treat with sulfur or copper based fungicides in dust or spray forms.  We find it more effective to apply spray via a spray applicator, as it may facilitate reaching the top of the tree.  You first treat in fall after the leaves have dropped.  You apply until the limbs are thoroughly drenched.  If the tree is badly infected, you can apply it again in late winter before the leaves emerge. 

Treatments:  We carry a number of products which will be effective in treating peach leaf curl.  They include: 

  • Copper Soap Fungicide by Ferti-Lome (copper octanoate) - OMRi approved for organic gardening 

  • Liqui-Cop by Monterey (active ingredient copper diammonia  diacetate complex) - Most effective 

Note:  As with all chemical treatments, please read the instructions thoroughly before application. 

Please review the UC Integrated Pest Management link for a thorough discussion.  

University of California Integrated Pest Management https://ipm.ucanr.edu/PMG/PESTNOTES/pn7426.html 

Dominic Gamache
Previous

Ravishing Ranunculus