Peach Leaf Curl: Particularly Bad This Year & What You Should Know

Peach Leaf Curl is Everywhere in Alameda County - Spring 2023

by Jim Farr

Peach Leaf Curl: The first signs are red spots on the leaves, which soon become thick and puckered. The leaves eventually turn yellow and drop off.

The weather this Winter and Spring has been unusually wetter than normal and while the rain has helped replenish our reservoirs there have been some other effects which you likely have noticed if you have peach or nectarine trees in your yard. You may have observed the leaves on your peach or nectarine trees looking puckered, curled, discolored, and falling off. This is a sign your tree has peach leaf curl which, due to the heavier-than-normal rains, is particularly bad this year. This can be very disconcerting for those owning peach or nectarine trees but you are not alone. Here at the Alameda County Master Gardener Help Desk, we are getting inundated with questions about peach leaf curl showing up in yards all over the county.

Peach leaf curl is a very common fungal disease that affects many peach and nectarine trees in our county. It is controlled by dormant spraying with a fungicide, typically copper-based, in the Winter months but this year even some trees that have been sprayed still show signs of peach leaf curl.

Here are some things that you should know if your tree has become infected:

Peach Leaf Curl will not kill your trees. While the tree may look sick, peach leaf curl will not kill your peach and nectarine trees. However, it will affect the quantity of fruit you will obtain from the tree.
Resist the temptation to remove the infected leaves. The leaves may look very sick, but they still will photosynthesize, just less efficiently. In other words, there will be enough photosynthesis to even support some fruit growth depending on the severity of the disease.
Once the signs of peach leaf curl appear, there is no reversing it. There is no treatment you can give the tree that will stop or eliminate the disease once it has appeared in the Spring.
Be sure to spray the tree with a copper-based fungicidal dormant spray next Winter. In fact this should be done every year since peach leaf curl is so prevalent in our county. Because the disease is so much worse this year, spraying during the next dormant period will be especially important.
Lastly, you might be wondering if there are any peach and nectarine varieties resistant to peach leaf curl. A few peach varieties are available that are resistant or partially resistant to leaf curl. Currently, available resistant varieties include Frost, Indian Free, Muir, and Q-1-8. The peach cultivar Frost is reportedly very tolerant but must receive fungicide applications in the first 2 to 3 years. Redhaven peach and most cultivars derived from it are tolerant to peach leaf curl. There are fewer resistant nectarines, although Kreibich is one such variety.

References

For more information read the original article on Peach Leaf Curl that appeared in this blog last year.

Another Peach Leaf Curl reference you might find helpful is from the Integrated Pest Management website

Still Need Help?

Would like more information or help with other gardening issues? Email us at acmg@ucanr.edu. Or contact us through our website http://acmg.ucanr.edu/Contact_Us/ .