What You Need To Know About Peach Leaf Curl

Peach Leaf Curl Image

What is a peach tree in a backyard if we cannot enjoy the fruit from the tree!  This year, in most areas of British Columbia Peach Leaf Curl has become quite obvious.  In this article we will discuss what Peach Leaf Curl is, how and when it happens as well as what you can do to prevent it form happening to you again!

Peach leaf curl is a disease triggered by a fungus (Taphrina deformans) that is active in early spring during cool and wet conditions.  Leaf infection usually occurs in March and April when leaves first emerge from the buds.  Later, infected leaves appear thicker than normal, curled and discoloured.  During summer months, the affected leaves will prematurely turn brown and fall to the ground.   Once the disfigurement is seen, it is too late for control, but plans can be made to prevent it from happening again but you must take action.

The disease impacts all peach and nectarine trees and some apricots.  It impacts the appearance of the plant and, when severe, will also impact the fruit quality.  Affected trees look unthrifty, but there is no immediate harm to the plants.  In some regions, the disease is seen only every 3 or 4 years as weather conditions are not conducive to infection every year.  In other regions where spring is typically wet, disease infection can occur every spring and slowly weaken the plant.

Management is done in a number of ways.  On trees already showing the infection, there is no effective control measure.  Removing the affected leaves as they turn brown will improve the appearance of the plant but it will not solve your problem.  Spraying is not effective if done later in the spring once the disease is visible.  Strict sanitation is an important practice for most diseases but for peach leaf curl, sanitation will not prevent new infections the following year.  

Trees showing peach leaf curl should be scheduled for a fungicide spray the following spring because this fungus wll actually overwinter and given the right conditions penetrate next years foliage once the bud breaks.  The best control is obtained with lime sulphur just before bud swell (when leaves emerge from the buds).  The product is used by organic farmers and is readily accessible at garden centers.  Lime sulphur is generally safe but will cause burning if applied on emerged leaves.  Be sure to thoroughly cover the bark and trunk of the tree while spraying.

There is no truly resistant cultivar, but some peach varieties are less susceptible to the problem.  Gardeners should verify with their local horticulturists for the peach and nectarine cultivars most appropriate for their region.  Redhaven and cultivars derived from Redhaven have shown less infection in university trials.

Healthy Peach Tree

Happy Gardening!

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Guest post by Mario Lanthier - Bylands Crop Health Advisor

Mario believes in prevention and trying to solve problems for the long term.  He has worked in the horticulture industry since 1980 and designs programs for management of insects, diseases, weeds and rodents.