Peach leaf curl: identification, treatment & prevention

Peach leaf curl is a common springtime sight on peach or nectarine trees with young leaves distorting and changing colour. Learn how to spot peach leaf curl and what to do if your tree shows signs of infection.

Peach leaf curl is a very common fungal disease that affects peach trees (Prunus persica), nectarine trees (Prunus persica var. nucipersica) and also some apricot trees (Prunus armeniaca). However, it is not all bad news as there are methods of peach leaf curl prevention that can help control and combat the issue. There are also varieties that are less susceptible to peach leaf curl. Fortunately, peach leaf curl does not completely damage a crop of peaches.

What is peach leaf curl?

Peach leaf curl is a disease caused by Taphrina deformans. It is quite prevalent in all peach and nectarine cultivars and has also been seen to affect apricots and even some almond trees (Prunus dulcis). The fungal disease affects all aspects of the tree, including leaves, fruits, shoots and blossoms.

Peach leaf curl symptoms

The signs of a peach leaf curl fungal infection usually appear within the first two weeks after the leaves emerge in spring. The symptoms to look out for include leaves curling, becoming crumpled or distorted, and turning yellow, orange or red in colour.

Peach leaf curl disease causes a coating of white fungal spores on the leaves, which is sometimes accompanied by reddish warts. The velvety spores spread readily throughout the tree. The diseased leaves will fall quickly because they are unable to photosynthesise. Consequently, the tree is defoliated and must expend energy to put out new replacement leaves, resulting in a loss of overall vigour. The replacement leaves will be healthy, but they will cost the tree a lot of energy to grow.

Shoots and blossoms infected with peach leaf curl will look distorted, and diseased fruit will have scaley areas. If not treated, the peach leaf curl fungal disease can kill a tree within two to three years.

As the Taphrina deformans fungus can live even in the tiniest of tree crevices, it is impossible to remove all infected parts. Any pruning of the tree will result in open wounds that serve as an access point for disease to enter the tree. The fungus overwinters in the tree’s buds or cracks and enters the leaf tissue in spring when the buds open. Wet and windy weather is ideal for the spread of peach leaf curl fungus.

The good news is that peach leaf curl does not completely wipe out a crop and the tree is able to replace diseased leaves with new healthy leaves. That said, there are also measures that can be taken to control or combat the disease.

Treating peach leaf curl

There are limited options when it comes to peach leaf curl treatment. A copper-based fungicide can be used to treat trees that have visible symptoms of peach leaf curl disease. There are very few copper-based fungicides available to home gardeners; Nonetheless, in light of what is available, the higher the amount of copper in the fungicide, the more effective it will be. The time to apply peach leaf curl fungicide is when the buds begin to swell from mid-January until February. Spray once and then again two weeks later. Apply the treatment again in autumn, after the leaves have fallen, to prevent the fungus from overwintering in the tree’s crevices.

If a tree shows signs of peach leaf curl, consider pruning it in autumn before applying fungicide to help reduce the number of spores that can overwinter.

Once a tree is infected, there is little that can be done to get rid of the disease that season. You can thin the fruit to lessen the demand on the tree and apply a balanced fertiliser in mid-June to provide the tree with nutrients to replace leaves. Our Plantura All Purpose Plant Food offers a balanced mix of nutrients to promote healthy tree growth. Water the tree regularly to assist the tree in growing new leaves; a tree short of water will be further weakened and will struggle to regrow the required foliage.

Make sure to pick up any affected leaves or fruit on the ground to prevent spores spreading to other trees. Dispose of diseased plant matter in the household waste bin; do not add it to the compost pile.

Is there an organic control for combatting peach tree leaf curl? Well, there is no proven method to combat the fungus in a natural way. However, some growers in the United States claim to have successfully treated peach leaf curl. Some claim that spraying their peach trees with a concentrated garlic extract helps and others claim spreading chicken manure around the tree can help even when the first signs of infection are spotted. Please keep in mind that these are unproven claims, and more research is required if you wish to consider these treatment methods.

How to prevent peach leaf curl disease

There are a few ways to help prevent peach leaf curl fungal disease. These include planting a more tolerant variety, spraying trees twice a year in spring and autumn, pruning the trees before winter, overwintering the trees appropriately and removing affected leaves and shoots swiftly.

Choose a peach leaf curl resistant variety

There are some peach tree varieties that are more resistant to peach leaf curl. These varieties are good option for home gardeners who wish to reduce the likelihood of the disease. More tolerant varieties include ‘Avalon Pride’, ‘Red Haven’, ‘Redwing’, ‘Robin Red Breast’ and ‘Advance’. It is also claimed that white-fleshed peaches are less susceptible to the disease. However, it should be noted that there are no varieties that are completely resistant to Taphrina deformans, and several cultivars’ resistance to the fungus is also in doubt. Trees with no known resistance can be sprayed with a fungicide annually after the leaves have fallen, usually in late November, and also again before new leaves emerge in spring.

Pruning

Pruning, including the removal of diseased leaves and shoots, can be employed as a preventative measure to help combat peach leaf curl. Regular pruning will increase the tree’s air circulation, allowing it to dry faster after rain. Pruning stimulates the growth of new shoots and leaves, and more healthy and strong shoots will mean more leaves. A tree with many leaves that becomes infected with peach leaf curl disease will lose some of them, but the more leaves it has, the less impact that loss will have.

Even if the tree has already been infected, removing any diseased leaves and shoots before the white spores appear can help to limit the amount of fungus that enters the tree to overwinter there and cause problems the following year.

Overwintering

As mentioned earlier, wet and windy weather are ideal conditions for fungal spores to spread. One method of prevention is to cover the peach tree with plastic sheeting from when the leaves fall until late spring. This method of keeping shoots dry can help prevent fungal infection. If you grow your peach tree in a pot, then overwinter it in a greenhouse or undercover to protect it from the elements.

Now that you know how to treat and prevent peach leaf curl. Maybe you want to try your hand at growing a nectarine tree? It is closely related to the peach and with the right know-how you can expect a bumper crop of delicious juicy nectarines. Find out how to grow and care for nectarines in your garden.