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.
Yes, once it starts, the problem is likely to happen every year but it's not worth getting worried about. Simply do as instructed - pick off and pick up all disease leaves, bin (never compost them) them, feed and water the tree well soon as you see it happen, and the tree will recover beautifully.
Plants often recover on their own from leaf curl caused by transplant shock within a couple of weeks.
For effective control, treat trees just after leaves have fallen, usually late November or December. A second application in late winter before buds swell can be considered, especially in areas with high rainfall or during wet winters. Don't apply fungicides during the growing season because they won't be effective.
Your Peach or Nectarine Will Survive
Peach Leaf Curl will cause the leaves to fall off and the fruit production of the tree can be affected. However, gardeners are usually relieved to hear that this disease rarely kills trees and can be easily managed if treated with a fungicide during the dormant season.
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.
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.
Leaf curl can usually be controlled satisfactorily by a spray of a suitable registered fungicide at any stage of dormancy. 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.
Over-watering.
Overdoing your watering can have a similar effect to underwatering. You may also find your plants produce an excess of foliage but few tomatoes. Leaves might yellow and wither, or they could curl.
Peach leaf curl is not difficult to control. A single fungicide (copper or chlorothalonil) application made in the fall after leaves have dropped or in spring before bud swell will control the disease.
Several other fungicides that are equivalent or even more effective than copper for managing peach leaf curl are ziram, chlorothalonil (Echo or Bravo), and dodine (Syllit) when applied at the optimal time. Ziram is most effective.
The fungus causes the growing cells at the leaf margins to multiply quickly and randomly which results in the curled and distorted appearance. The fungus then wastes no time producing spores on the surface of the leaf that spread to other leaves and fruits on your tree or other trees in the area.
It's also a good idea to rake up and bin the fallen infected leaves, to help reduce the number fungus spores in your garden.
Copper fungicide is effective against peach leaf curl. There are also more broad spectrum horticultural dormant oil sprays available by that type of generic name.
Pour 2 cups of vegetable oil and ½ cup of dishwashing liquid into a jar, mix it well then add 1 tbsp of concentrate to 1 litre of water. Spray to cover the top and bottom of the foliage.
In the case of zealous gardeners, leaves may curl up due to excess fertilizer. Overdosing occurs when you don't respect the frequency or doses prescribed by the manufacturer. Other signs indicate that your plant has been over-fertilized. For example, brown spots appear on the foliage.
To control leaf curl, spray with PLANThealth Copper Fungicide soon after pruning, just before bud burst happens in Spring. Disease is often carried between plants by sap sucking insects. Use Organic Super Spraying Oil to control these insects before they can spread disease.
Prevent Leaf Curling
Another sign of magnesium deficiency, this problem can also be tackled with the help of Epsom Salt. Mix two table spoons in a gallon of water and spray your curled foliage with the solution until the leaves look perfect again.
Tree to tree spread of the pathogen occurs by airborne ascospores that can move longer distances or by blastospores, which are disseminated in splashing water. Leaves and the occasional fruit infections occur only on young plant tissue.
The safest, effective fungicides available for backyard peach trees are copper soap (copper octanoate) or copper ammonium and are known as fixed copper fungicides. Apply either of these copper products with 1% horticultural oil to increase their fungicidal effectiveness.
Use ACV for fertilising your plants
Simply mix water with your apple cider vinegar and pour it into a sprayer or watering can. Spray this solution at the base of the plant, avoiding watering the leaves as this can often lead to wilting.
Organic Control Methods for Leaf Curl
Spray at bud-swell with copper hydroxide or copper oxychloride and ensure thorough coverage over all branches. Timing is critical to prevent the fungus entering the plant when new leaves are vulnerable.