Winter slows down many garden pest problems, but it's also a key time for gardeners to take actions to prevent certain pest problems that occur in the spring. One of the most important of these preventive practices is application of dormant treatments for peach leaf curl.
Caused by the fungus Taphrina deformans, peach leaf curl is a very serious disease, which affects only peach and nectarine trees. Its most distinctive symptom is distortion, thickening, and reddening of foliage as trees leaf out in the spring. Damaged leaves often die and fall off trees but will be replaced with new, usually healthy leaves once the weather turns dry and warmer. A leaf curl infection that continues untreated over several years will contribute to a tree's decline and reduce fruit production.
To prevent peach leaf curl, peach and nectarine trees must be treated with preventive fungicides during the dormant season. The best time is after leaves have fallen, usually in late November or December, but in wet climates or during a wet winter, a pesticide application can be made in late winter (January or February) just before or as buds swell.
Although gardeners won't notice the symptoms until spring, there is little that they can do at that time to reduce leaf curl. Treatment applied after trees leaf out or after symptoms appear won't be effective. Removing affected leaves or shoots will not reduce the problem. There are a few peach varieties that are resistant or partially resistant to leaf curl. These are Frost, Indian Free, Muir, and Q-1-8.
Dormant Treatment Materials
Leaf curl symptoms on green peaches. [J.K.Clark]
The fungicide chlorothalonil is effective, and several trade named products are available (Daconil, Fung-onil, Ortho Garden Disease Control, etc.). However, care must be taken in handling chlorothalonil, since this active ingredient is listed as a likely carcinogen and can also cause severe eye or skin irritation if applied improperly or if proper protective clothing and equipment aren't worn.
Bordeaux mixture, which gardeners can mix up themselves by following the directions in the UC IPM publication Pest Note: Bordeaux Mixture, is also effective, but finding the ingredients and mixing up Bordeaux is more work than some gardeners may be willing to do. For gardeners wishing to take the extra time to make Bordeaux mixture, the primary ingredients are powdered copper sulfate in “bluestone” form and either hydrated lime (calcium hydroxide), such as used in making plaster, or quick lime (calcium oxide). Neither of these latter ingredients is a registered pesticide. Copper sulfate can only be found in large bags, so unused product will remain viable for years when kept in the garage or shed. Be sure to wear goggles, gloves, and a dust and mist-filtering respirator when working with hydrated lime and mixing up the solution.
If bud swell and flowering is already occuring in your area, it's too late to treat. For more information about this disease and its management, see the UC IPM publication Pest Notes: Peach Leaf Curl.
Always read and carefully follow all precautions and safety instructions provided on the pesticide container label, as well as any other regulations regarding the use of pesticides. Not following label directions, even if they conflict with information provided herein, is a violation of state and federal law. No endorsem*nts of named products are intended, nor is criticism implied of products not mentioned.
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FAQs
Fungicide hints …
Spray your trees twice, the first time in late November and the second time in early February.
What is the best spray for leaf curl on peach trees? ›
Best Treatment for Leaf Curl
To prevent Leaf Curl, spray trees thoroughly during winter with a fungicide spray like Yates Lime Sulfur, when the trees are dormant and before bud swell (when leaf and flower buds start to enlarge).
Is it too late to spray for leaf curl? ›
Controlling peach leaf curl with fungicides
Most effective control is achieved by spraying when the buds are swelling but before they have opened. It's not possible to control the fungus once it's entered the leaf. Poor disease control is usually a result of spraying too late – that is, after budswell.
Will peach leaf curl go away on its own? ›
Leaf curl disease shows up in spring, does the damage, and then disappears (until next spring). It will have disappeared by late summer. However, you may still be able to find signs of it, if you know what to look for. If your trees were infected last spring, they should have completely recovered by mid to late summer.
What month do you spray peach trees? ›
What Chemicals Do We Use?
| Month | Spray |
|---|
| January | Dormant Oil Hatchet – Insecticide 800 Plus – PH buffer |
| February (pink bud) | Imidan 70 W (insecticide) Captan (fungicide) 800 Plus – PH buffer |
| March | Bravo or Imidan 70 W (insecticide after flowers are gone) Captan (fungicide) 800 Plus – PH buffer |
9 more rowsOrganic approved sprays such as Neem Oil, Horticultural Oil, Bi-Carb and Copper all work but we've found Copper to be by far the most effective against leaf curl. Third, and likely the most successful for home growers is to keep your trees out of the rain!
What is the best product for peach leaf curl? ›
The synthetic fungicide chlorothalonil is the only non-copper fungicide available for managing peach leaf curl in the backyard orchard.
Does apple cider vinegar help with leaf curl? ›
Leaf curl starts appearing in early spring on stone fruit trees. Spray a mixture of apple cider vinegar and water in winter and early spring when buds appear, then every couple of weeks. This will help with brown rot, black spot and leaf curl, to name a few.
What to spray on peach trees in winter? ›
Horticultural oils are usually applied in winter to early spring, after leaves drop in the fall and before buds break, to control San Jose scale and white peach scale, as well as overwintering mites.
What spray kills leaf curl? ›
Yates Leaf Curl Spray is a broad-spectrum fungicide that is suitable for use on fruit, vegetables and ornamentals, for controlling leaf curl, leaf spots, blights, downy mildew and many more fungal diseases.
How to make Bordeaux spray
- Mix lime and water. Dissolve 100 grams of builders' (hydrated) lime in half a standard (plastic) bucket of water. ...
- Mix copper sulfate and water. Dissolve 100 grams copper sulphate in a separate half bucket of water. ...
- Spray. Pour the mix into a sprayer. ...
- Wash.
Those fruits are still okay to eat—just cut away the affected area. Since fungal spores may also be present on the fallen leaves, it is a good idea to pick up all fallen leaves.
Can plants recover from leaf curl? ›
Plants often recover on their own from leaf curl caused by transplant shock within a couple of weeks. Provide plenty of water as your tomatoes settle in. To minimize transplant shock in the future, make sure to slowly acclimate seedlings to garden conditions before planting and gently handle the root ball.
Can leaf curl be cured? ›
The most common method of treating leaf curl is to spray sulfur or copper after leaf drop in the fall and again in the spring. Conventional thought is that once the leaves are infected, there is nothing you can do to fix it during the season.
Can I treat leaf curl in summer? ›
Since the fungus overwinters on the bark and in the bud scales, it is vulnerable to the fungicide. If the trees are badly affected, you can spray again in the late winter or early spring, when the buds swell. Do not use these fungicides in warm weather or after the leaves and flowers come out of the buds.
When should you not spray fruit trees? ›
You'll want to avoid spraying when flowers are in full bloom as it can damage the flower and, therefore, the immature fruit, but this is also an optimal time for pests and diseases to infect the tree. And if you overcompensate spraying right now, you could harm the bees trying to pollinate.
What should I use for peach leaf curl? ›
In addition, consider applying a single fungicide spray in the fall after leaf drop or in the spring before buds begin to swell to control peach leaf curl (and also plum pockets). Effective fungicide active ingredients include chlorothalonil, copper (e.g., Bordeaux mixture), and ferbam.
When to spray copper sulfate on peach trees? ›
Peaches: Spray copper or a good dormant fungicide three to four times between December and bud break. Spray copper or lime-sulfur before fall rains and in spring just before bud break; apply sulfur weekly during blooming and again after all petals have fallen.
