Ruud Kleinpaste: Leaf Curl on Stone Fruit

One of the common queries from the Garden involves the phenomenon of leafcurl on the leaves of peaches, nectarines, apricots, almonds …. STONE FRUIT in other words.

It is caused by the fungus Taphrina deformans.

The leaves (especially in spring) are discoloured and contorted (if there is such a word) disfigured and looking quite awful.

Colours vary from pale green to pink and deeper purple colours, but the distortions are very diagnostic: as if the leaves have become a lot “thicker”

The affected leaves fall off the trees along with infected small fruits.

Infection

As soon as the leaf buds have “swollen” to produce spring-time leaves, the infections take place. Later in spring and early summer, when most of the affected leaves have fallen off, the leaves appear to be “normal, but the tree will have been weakened. By then the damage has been done.

With newly-formed peach leaves in spring, you are NOT advised to spray copper on those leaves, as copper often causes “burn” on those leaves and - besides – you’re too late controlling the fungus at that time.

A spray with Myclobutanil (“Fungus fighter”) might be more effective as that (non-organic) material will control the fungal infection – albeit too late for that year’s crop!

Timing of Infection

The reason we’re talking about leaf curl at this time of the year (July) is that from Late Autumn to Early Winter (right now!) the fungal spores of Taphrina deformans are infecting the leaf buds that are being formed on the twigs for the new spring growth.

Control

Grab yourself a double dose of Copper spray (or a mixture of Copper and Sulphur (both regarded as organic sprays) and drench those new buds two or three times (2 weeks apart). I have the feeling that you can’t go wrong with three or even four sprays of copper from all angles, so the buds are thoroughly sprayed and the fungal spores are given a run for their money!

Some folk advise to do apply another copper spray just before the leaf buds swell (in spring) and  produce leaves.

But it’s quite simple: if you can control the Taphrina deformans at this time of the year, you’ll control the leaf curl too and have a much better crop of stone fruit in spring.

If you still get some leaf curl on the new leaves, a quick dose of fungus fighter will “mop up” the fungus before it goes into its summer state.

Hygiene

Don’t forget to pick up fallen, infected leaves and fruit from the ground underneath the tree.

See omnystudio.com/listener for privacy information.