Peach leaf curl is a fungal infection of peaches that can cause defoliation and loss of the crop, depending on how severe it is. This fungal infection can be treated, and there are ways to deal with an already existing case of peach leaf curl so that the year's crop isn't a total waste. Peach leaf curl is quite common in some parts of the world, and sometimes it is a good idea for a peach grower to work together with neighbors who also have peaches, to ensure that all of the trees in a small area are protected and treated so that they do not infect each other.
Causes of the Infection
This condition is caused when a peach tree is colonized by the fungus Taphrina deformans. The spores of this fungus work their way into the leaf buds in the early spring, and when the peach tree starts to leaf out, the fungus goes to work. A tree afflicted with peach leaf curl will have heavily distorted leaves that typically turn red or yellow while curling, clubbing and eventually dropping off. The fungus also can attack the fruit, rendering it inedible or preventing it from maturing.
Treating Infected Trees
If a tree manifests signs of peach leaf curl in the spring, it should be treated with extra nitrogen to reduce the stress on the tree, and some gardeners also recommend routine heavy watering to eliminate drought stress. By reducing stress, gardeners increase the chance of saving the peach crop. It also is a good idea for the peach grower to thin out the young peaches more than usual so that the tree can dedicate resources to producing a smaller crop of really good peaches rather than a larger crop of mediocre ones.
After the leaves of a tree with a case of peach leaf curl drop off, they should be raked up and burned, because the spores of the fungus could otherwise remain nearby over the winter and infect the tree again in the spring. Then, the tree should be treated with a copper-based fungicide to kill the spores. Some gardeners like to treat in the fall and then again in the spring, right before the tree buds out, ensuring that the spores truly are eliminated.
Care is advised when using fungicides. They should never be used around crops that are going to be picked for food, because many fungicides can adversely affect human health. It is also a good idea for the peach grower to protect plants underneath and near the tree, because fungicides can damage some plants, especially flowers. Facial protection for the nose, mouth and eyes should be worn while applying fungicides, and pets and other members of the household should be kept out of the area until the process has been completed.