Leaves turn waffled and bulging, curling inwards, yellowing to orange and red before drying brown and dropping: this is peach leaf curl (Taphrina deformans), the most feared attack a peach or apricot tree faces. Only preventive spraying, begun in autumn once leaves have fallen, saves the harvest.
Preventive care is required to avoid it.
This fungus (Taphrina deformans) is certainly the most fearful attack that peach trees or apricot trees can face, and will often hinder the tree as it tries to produce a normal peach harvest.
Although it is sometimes possible to control damage thanks to an adequate treatment applied at the right moment, peach leaf curl can nonetheless entirely destroy a harvest.
Here are our treatment guidelines against peach leaf curl:
How to recognize peach leaf curl
This disease mainly infects the different peach varieties, but can also appear on apricot trees and almond trees.
Here are the main peach leaf curl symptoms
Curled leaves yellow, then redden and dry brown
Leaves appear waffled and bulging.
Leaf edges curl and roll inwards.
They take on a yellowish color, turning orange and red before drying brown and falling off.
Sprigs are distorted and branches don’t have the same bearing anymore.
Inspect the fruit too, as infected peaches and nectarines can carry raised, wrinkled corky patches on the skin.
Nectarines are fuzzless peaches of the same species, Prunus persica, and are at least as susceptible to common peach diseases such as brown rot, so give them the same spray schedule.
When to treat against peach leaf curl
The fungus overwinters as spores on the buds
The fungus responsible for peach leaf curl spends the winter in the form of spores lying on the buds and in hollows formed by the sprigs.
As soon as the temperature reaches 50°F (10°C), the fungus starts developing and releases large amounts of spores.
Like most fungus, it mostly appears in warm weather while the ambient air is sill very moist.
That’s why treatment must be applied before this period, at the end of winter and at the beginning of spring, and best of all in fall, when leaves have fallen off.
A 1st spraying of Bordeaux mixture is required as soon as the autumn leaves have fallen.
Renew the spraying as early as late winter if temperatures rise above 50°F (10°C), following doses recommended on the packaging.
Afterwards, a third spraying is needed just when the first buds have appeared and burst.
Remember that for peach leaf curl, nothing is better than preventive treatment, it is the only effective way to treat against this fungus.
When peach leaf curl has appeared, it is already too late.
How to treat peach leaf curl
In fall
When leaves have fallen: pick leaves up and burn them to avoid having the disease overwinter in your garden.
This step is mandatory to keep leaf curl from appearing in spring.
In spring
Spray once more with Bordeaux mixture.
Spray the leaves until they’re running with the mixture, starting in late winter to early spring and continuing until late spring, every fortnight.
A clear plastic shelter over a wall-trained peach, kept in place from midwinter until late spring, keeps rain off the developing buds and can greatly reduce peach leaf curl infection without spraying.
Mix Bordeaux mixture fresh and use it the same day.
Treatment calendar against peach leaf curl
Peach leaf curl is beaten on the calendar, not on the symptoms: each spraying has its own window. Here is what the article recommends, season by season.
Treatment calendar against peach leaf curl
Timing
What to do
Why it matters
Autumn, once leaves have fallen
Pick up and burn the fallen leaves
Stops the disease overwintering in the garden
Autumn, straight after leaf fall
1st spraying of Bordeaux mixture
Mandatory step to keep leaf curl from appearing in spring
From late winter, above 50°F (10°C)
Renew the spraying at the dose on the packaging
The fungus starts developing and releasing spores at that temperature
At bud break
Third spraying
Buds are where the spores have spent the winter
late winter to early spring to late spring
Spray every fortnight until the leaves run with the mixture
Covers the whole warm, moist period when the fungus appears
Once the leaves have curled, the timetable has already been missed and only damage limitation remains.
What can be done if leaf curl has already appeared?
At most, propagation of the peach leaf curl can be slowed.
You must remove infected leaves, cut off the most sickly branches and spray again with Bordeaux mixture.
Thin the fruit on a badly stripped peach tree, because the few remaining leaves cannot ripen a full crop.
Regular maintenance of the peach tree is necessary
This regular care aims to reinforce fruit trees and thus increase their fruit bearing.
It is thus important, every winter, to perform a fruit-inducing pruning.
On a peach tree, though, pruning should not be too severe, or the tree will be weakened.
Provide organic fertilizer in spring and mulch the base of the tree to protect roots from frost spells in winter and from heat in summer.
Thin the young peaches so the remaining fruits stand about 6 to 8 inches (15 to 20 cm) apart along each branch, which prevents overbearing and lets the fruit size up properly.
Keep the mulch pulled backa few centimetres from the trunk, as material packed against the bark encourages collar rot.
Images: CC BY 2.0: Maja Dumat, Public Domain: Tomas Pocius
Written by Gaspard Lorthiois | Loves helping out, especially when it comes to growing things. Worked in herbal medicine, runs a farm, and dabbles in tech. Master's degree and engineer.
