It’s no fun when you have trouble with your fruit trees. In particular, peach trees sometimes develop curled leaves, which is concerning when you first see it!
So, why are the leaves on your peach tree curling? Peach leaf curl leads to swollen, curled, or twisted leaves, reducing tree vigor and fruit yield. The cause is the fungus Taphrina deformans, which can survive over winter in bark and thrives in cool, wet conditions (50 to 70 degrees Fahrenheit). Fungicides can help to prevent peach leaf curl.
Luckily, peach leaf curl is rarely fatal for trees – as long as you are on top of things. There are a few things you can do to help your peach tree survive and recover from this disease.
In this article, we’ll go over what peach leaf curl is and what it looks like. We’ll also talk about treatments and prevention for peach leaf curl, along with some peach varieties that resist the disease.
Let’s get started.
Why Are My Peach Tree Leaves Curling?
Peach Leaf Curl (also called Leaf Curl) is a fungal disease that affects peach trees. It is one of the most common peach tree diseases, and it is found on every continent except Antarctica.
The disease also sometimes affects nectarines and cherries, and rarely affects almonds or apricots (these trees are all in the same family as peaches: Rosaceae).
Peach leaf curl is caused by the fungus Taphrina deformans, which thrives in cool, wet weather conditions (over 95% relative humidity seems to be a trigger point). This fungus can survive in the bark and bud scales of peach trees over the winter.
According to the University of Wisconsin Extension, fungal spores cause infection in leaves before and after budding. Infection is more common after a mild winter, and more likely at temperatures of 50 to 70 degrees Fahrenheit (10 to 21 degrees Celsius).
According to the University of Illinois Extension, the fungus needs 12 hours or more of moisture (rain or high humidity levels) to infect leaves. When temperatures go above 70 degrees Fahrenheit, leaf infection slows down drastically or stops entirely.
If warm temperatures (70+) come after bud swell and leaves grow quickly, it is less likely that peach leaf curl will infect a tree. In fact, the disease can rest dormant in the bark until a spring comes along where the right weather conditions emerge for the fungus to take hold.
New spores form on top of infected leaves. These spores can then travel via wind or splashing water (from rain or irrigation), spreading the disease further.
What Does Peach Leaf Curl Look Like?
Early in the season (late spring), leaves infected with peach leaf curl have areas that may look:
The leaf colors may change from deep green (healthy leaves) to light green, yellow, red, or purple (diseased leaves).
As the disease progresses, you may see a powdery gray color on the upper leaf surface (these are the fungus spores). At this point, the leaves will look more like velvet.
When the weather gets warm and dry in the summer, the infected leaves turn brown and eventually fall off. The tree will regrow new leaves (sometimes in June or July of the same year), but the disease may persist if it survives over winter in the bark.
According to the University of Massachusetts, the production of new leaves can stress the tree. This may reduce the crop in the current year and possibly the following year as well.
Remember that peach leaf curl affects more than the leaves on an infected peach tree:
- Branches infected with peach leaf curl have stunted growth, may look thick or distorted, and produce small yellow leaves.
- Flowers infected with peach leaf curl may drop off the tree, which causes decreased fruit yield.
- Fruit on infected peach trees may also suffer (more on this below).
Does Leaf Curl Affect Fruit?
Peach leaf curl will sometimes affect the fruit on the tree. For one thing, the reduction in leaves will reduce the tree’s energy production (reduced photosynthesis), leading to a less vigorous tree with decreased fruit yield.
However, peach leaf curl can also affect the appearance of fruit. Sometimes it looks normal, but other times the diseased fruit is bumpy and red, often falling off the tree before ripening.
Can You Cure Peach Leaf Curl?
You cannot cure peach leaf curl in the current season. However, you can take some steps to keep the tree alive and healthy.
Luckily, peach leaf curl is not usually deadly to trees. However, it can weaken trees, which can lead to death during a drought or some other problem (like winter injury).
Should I Remove Leaves With Leaf Curl?
Unfortunately, removing leaves with leaf curl will not eliminate the disease. Remember that the Taphrina deformans fungus survives in bark over the winter.
However, there are some treatments and preventative measures you can use to help your peach tree recover to a healthy condition.
What Is The Best Treatment For Peach Leaf Curl?
The following steps can help infected peach trees to survive leaf curl:
- Water consistently (provide 1 inch of water per week when the weather is dry)
- Apply nitrogen fertilizer (this helps to replace lost leaves, which need nitrogen to grow. Don’t apply nitrogen too late in the season – Penn State University suggests fertilizing by June 15).
- Thin fruit (this reduces the demand for water and nutrients from the tree)
There are also some fungicide sprays available to help treat peach leaf curl.
When Should I Spray My Peach Tree For Leaf Curl?
- Chlorothalonil (Bravo)
- Lime sulfur
- Fixed coppers (copper compounds like Kocide, COCS, or Bordeaux mixture – these can also help with bacterial spot)
Before applying fungicide, check with your town or city on rules for pesticide, herbicide, and fungicide sprays. Always read the label first!
When applying fungicide, spray at one of two times:
- In the fall, before defoliation.
- In the spring, before buds start to swell.
If the disease is persistent and severe, you might want to spray at both times.
Remember that these fungicides are preventative measures. They are meant to prevent the disease from appearing in the following year.
If your tree already has signs of peach leaf curl, it is not likely that you can eliminate the disease this year.
How Do You Keep Peach Trees From Curling?
One of the best ways to prevent peach leaf curl is to choose resistant varieties.
Here are some peach tree varieties that have resistance to peach leaf curl:
- Frost – this peach tree variety is hardy in Zones 5 through 9. It grows to a height of 15 to 25 feet with a width of 12 to 18 feet at maturity. The flowers are pink and the fruit is freestone with yellow flesh and yellow-green skin with some light red coloring. This tree needs around 700 chill hours to break winter dormancy. You can learn more about Frost Peach Trees from Nature Hills.
- Indian Free – this peach tree variety is hardy in Zones 5 through 9. It grows to a height of 12 to 18 feet. The fruit is freestone with yellow and red skin, with crimson and cream colored flesh. This tree needs 700 to 1000 chill hours to break winter dormancy. You can learn more about Indian Free Peach Trees from Grow Organic.
- Muir – this peach tree variety is hardy in Zones 6 through 9. It grows to a height of 12 to 15 feet with a width of 10 to 12 feet at maturity. The flowers are pink and the fruit is freestone with orange flesh and bright yellow skin with some light red coloring. This tree needs 600 to 700 chill hours to break winter dormancy. You can learn more about Muir Peach Trees from Nature Hills.
- Q-1-8 (Salish) – this peach tree variety is hardy in Zones 5 through 9. It grows to a height of 10 to 12 feet at maturity. The flowers are pink and the fruit is semi-freestone with white flesh and skin that is yellow, orange, and red. This tree needs 700 to 800 chill hours to break winter dormancy. You can learn more about Q-1-8 (Salish) Peach Trees from Nature Hills.
Note: the “Redskin” variety (and any peach variety derived from it) is highly susceptible to peach leaf curl!
Now you know why your peach tree leaves are curling and what causes peach leaf curl. You also know how to prevent the problem and how to help infected trees to survive the disease.
I hope you found this article helpful. If so, please share it with someone who can use the information.