Curly leaves on nectarines and peach trees

Peach leaf curl is a disease that infects peaches, nectarines, almonds, and other Prunus species. It is caused by the fungus Taphrina deformans and occurs wherever peaches and nectarines are grown.

Peach and nectarines have been heavily impacted by leaf curl this year and even trees that were sprayed with a copper based spray at the end of winter seem to still be showing some signs of the disease.

Symptoms are visible in spring and summer and appear as leaves with raised lumpy light green and red patches that are curled up.

Later the colour fades as the fungus begins to produce masses of powdery grey spores on the upper surface of the leaf. Shoots can be thickened, distorted and yellow-green in colour and if heavily infected, may be killed.

Symptoms in fruit are raised, irregular rough patches that are often red in colour and fruit may fall prematurely. Once the symptoms are visible, it is too late to spray.

This disease weakens the tree if it occurs year after year and results in reduced yields. Leaf curl can usually be controlled by a spray of copper fungicide at any stage of dormancy.

Most effective control is achieved by spraying when the buds are swelling but before they have opened. Spray all the swelling buds as a preventative spray with copper oxychloride. Once the buds have burst open, it is too late to spray.

Where the disease has been difficult to control a program of 3 sprays may be required:

1. Apply the first spray in autumn, at leaf fall.
2. Apply the second spray immediately before budswell at the late dormant stage.
3. Apply the third spray about 1 week later at budswell.

To help control spread, clean up any fallen leaves from previous infections and dispose of in the bin (not compost) to minise spores spreading.

Trees need to be sprayed from mid to late winter from bud swell, until the leaves emerge.

• Practice good garden hygiene throughout the warmer months by removing any leaf litter and fallen fruit and placing it in the bin. 
• Mulch may also be replaced to reduce spore load from the ground. 
• Boost plant health with fertilser and seaweed solution applied at soil level. 

Trees can be sprayed at leaf fall in autumn as an extra dose of a copper based treatment and preventative such as Kocide.  It then should be reapplied as per directions at bud swell in late winter/spring and again at bud burst