Plants affected
Peaches, nectarines, almonds and apricots.
Symptoms
Symptoms of peach leaf curl. Photograph copyright Tim Sandall In early spring young leaves are swollen and distorted, and appear to have large blisters coloured whitish green, red or pink. As they mature the leaves become covered in a white, powdery bloom. The leaves often fall in large numbers leaving the tree virtually bare, although a second flush of healthy foliage will appear. Occasionally, fruit may be covered in blistered patches.
Cause
Erect a polythene or glass structure to cover the top and front of the tree between January and mid-May. Image: Tim Sandall Peach leaf curl is a fungal disease, which, if left untreated, puts trees under severe stress due to the excessive leaf loss. The white bloom consists of large numbers of fungal spores, but these do not infect the new leaves produced later in the year. Instead, they overwinter on the tree to infect the following year’s leaves.
Non-chemical control
- Collect and dispose of infected leaves before the bloom of spores appears. This is useful because it limits the number of spores overwintering on the plant.
- Erect a polythene or glass structure to cover the top and front of the tree between January and mid-May. Trees so sheltered from rain and dew show only very mild symptoms in comparison with unprotected trees. Ensure the sides are left open so that pollinating insects can enter. You should also carry out hand pollination.
- If a tree suffers leaf loss, boost its vigour with an application of fertiliser and make sure it is kept well watered and mulched.
Chemical control
Applications of fungicide must be timed carefully. A copper fungicide (Vitax Bordeaux Mixture, Murphy Traditional Copper Fungicide) or mancozeb (Dithane) should be applied as the buds begin to swell and then repeated 14 days later. Bud swelling normally occurs in late January or early February but may be delayed in colder districts. Spraying must be completed before flower buds open. Another application at leaf fall may also be beneficial.
