Leafcurl on stone fruit: peaches, Nectarines, plums, peachcotts, peacherines, apricots, etc always a sad sight on the leaves – it manifests itself in Spring and Summer – after flowering.

The leaves become distorted and discoloured (pretty yellow and orange coloration); when infestations are serious the number of leaves that drop off can be substantial, causing a reduction in photosynthesis and hence the ability of the tree to “feed itself”.

In spring the answer to “cure?” it will always be: “You’re too late!”… Right now, in late summer/Autumn you are still ahead of the 2024 infection game.

Taphrina deformans is the fungus that causes this leafcurl. Note how “deformans” is quite aptly chosen as a name, as it deforms the shape of the leaves quite obviously.

The disease becomes active at bud-break: when the leaves and flowers come out of the buds in spring. The spores of Taphrina deformans are already settled on those buds, making infection quite easy.

Those buds are initiated by the trees in autumn, which is just a few weeks away.

What to do?

First of all prune your stonefruit right now – after the last peaches, nectarines etc etc have been harvested, pruning can be done. Doing it this early has another advantage: you avoid bacterial diseases in the cooler months (late autumn/winter is a dodgy period for bacterial infections!)

Pruning now also reduces the amount of tree to spray in April.

Around mid April, when the leaves are falling off the deciduous stone fruit trees, the new buds for the next season are formed. Taphrina deformans will then be invading those new buds and overwinter on those buds to infect the trees again in spring.

First thing to do is to remove all fallen leaves from under the trees. That reduces infection chances.

Next thing is to apply a double dose of copper spray (copper oxychloride, liquid copper, or copper-sulphur mixtures, available form garden centres) on the remaining leaves and on the branches/twigs/buds of the tree.

Don’t worry about “burning the rest of the leaves off: they were going to fall anyway.

Use a “sticker” if you can, to increase coverage and stickability

Do this again a few weeks later and ensure good coverage of all parts of the tree.

This autumn spray exercise is the most important preventative thing you can do to avoid Leaf curl.

If you still get some infected leaves in spring there is no point in spraying with copper fungicides as that will burn those leaves quite badly. Best thing to do is to remove and get rid of infected leaves as much as you can – especially fallen leaves. “Getting rid of them” does not mean COMPOSTING them!!

Fertilising the tree in spring allows it to make new leaves and get some resistance to the infection, especially when you use Seaweed Tea and such marine-originated liquid fertilisers.

During the period when fruits grow and expand, check for fallen leaves that show signs of leafcurl, and get rid of them. REMEMBER “Getting rid of them” does not mean COMPOSTING them!!

Autumn is the time to start controlling leafcurl on stonefruit for the next fruiting season:

Some people use Lime sulphur; that’s OK too as a winter clean-up; seeing the trees are getting to dormancy this Lime Sulphur won’t harm the leaves either; but I think that lime may not be a great material for apricots as it has the ability to raise the pH levels.

A last smack of Copper spray before budburst should “mop up” the last surviving spores before the flowering and fruiting season begins again.

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