Leaf curl (Taphrina Deformans) is a widespread fungal disease that affects mostly peach and nectarine trees. If you have a peach tree in your orchard, it is most likely that you have experienced leaf curl infestation. Here’s what you need to know about this disease and how to treat your fruit trees organically.
This fungus affects the whole tree: the buds, the leaves, and the flowers (and sometimes the fruit), causing much stress for the tree and reducing its fruit production.
Can you eat the fruit from a tree infected with leaf curl?
It is safe to eat a fruit from a tree infected with leaf curl. However, once a tree is infected, you will probably end up with a smaller harvest during that season. When the infestation is severe, it reduces fruit production substantially. Moreover, it is advisable to thin the fruits once you spot the disease to give the tree the energy to heal.
What is Leaf Curl, and how does it affect your peach tree?
As I wrote, leaf curl is perhaps THE most common disease that affects peach and nectarine trees.
It first appears in the spring, about two weeks after the leaves emerge from the buds. That’s where you might notice red areas on the leaves of your tree. Perhaps, that’s the only good thing about this disease: it’s hard to miss those red spots on the leaves. I saw them for the first time from quite a distance, and I couldn’t figure out what they were. I even thought they were early fruits (I was a newbie! I still had a lot to learn…)
The reddish areas become thickened, causing leaves to curl and elongate in a distorted way. In a short time, the leaves turn yellow and brown and fall off, spreading the spores to the soil, continuing the cycle of infestation. The loss of leaves can lead to stress or even sunburn injury of the tree, and consequently, it will not produce the same quantity of fruit.
This disease thrives in cold, wet weather. It spreads by splashing water from irrigation or rain. As a matter of fact, if a tree is wet for two or more days, it favors the disease reaching maximum infection.
Is it possible to prevent and treat Leaf Curl on your peach tree?
Once you spot the first signs of leaf curl it is usually too late to treat the tree for that season. You will need to wait until the fall. Removing affected leaves won’t improve or eliminate leaf curl infestation. Even if new leaves grow after the distorted leaves have fallen, the disease will come back the next season if not treated.
There are several ways to prevent and treat this disease. Here is a list of what you can do:
- Plant a resistant cultivar such as Frost, Indian Free, Muir, and Salish Summer (aka Q 1- 8) for peach trees. For nectarines, resistant cultivar such as Kreibich.
- Remember that the conditions in which Taphrina Deformans spores proliferate are moist and cold weather. It is necessary to take care of the soil and to avoid water stagnation in order to prevent the spread of the disease.
- Treat the trees with a fungicide every year. Apply the fungicide twice: the first time in the fall, around November, when all the leaves have fallen. The second time in the spring, just before the leaves emerge from the buds. The second treatment is necessary, especially if you had a wet winter with high rainfall. Spray the entire tree profusely until you see the solution dripping.
- Keep the ground beneath the trees clean, especially during the winter.
- Prune the infected branches and remove the leaves. When doing this, don’t let them fall on the ground but collect them and, if possible, burn them. Don’t dispose of them in the compost bin.
- Sterilize your gardening tools regularly, especially after treating a tree with leaf curl.
- Thin out the fruit from the tree, water regularly, and apply organic fertilizers high in nitrogen.
- When watering your tree, avoid splashing water on the leaves.
Does Leaf Curl disease kill the tree?
Peach leaf curl is more ugly than dangerous; however, If you ignore this disease, in the long run, the tree will eventually die. Don’t neglect this problem, as your tree will get weaker and weaker year by year. Be prepared to act as soon as you spot the red signs on your leaves!
How to treat Leaf Curl organically
The most commonly used fungicides to treat Leaf Curl are organic copper-based products. Copper is undoubtedly a valid fungicide, and its use is allowed in organic farming. When used in massive doses, however, it can pollute the soil, making it a toxic environment for the micro-organisms that live in it. If used near waterways, it can harm some aquatic species.
It is, however, possible to prepare a powerful fungicide at home with baking soda. The recipe is simple and easy to remember:
Recipe for a powerful fungicide spray against leaf curl:
For one gallon of water:
- add 1 tbs of baking soda
- 20 drops of tea tree essential oil
- 20 drops of alcoholic propolis.
Boil the water for a few minutes, then let it cool. Strain the solution into a spray bottle.
At this point, you can spray the preparation on the peach tree. If you use it as a preventive treatment, spray it in autumn and at the end of winter every 3 days for 10-15 days. Do not spray in case of rain.
As an alternative, lime sulfur fungicide is a product allowed in organic farming, and can also be used. It is also active as an insecticide.
CAUTION: When using pesticides, always read and follow the label for usage and wear protective clothing and gear. Keep the pesticides/fungicides away from the reach of children!
What are other diseases caused by a fungus that can affect your peach tree?
As much as eating peaches from our backyard orchard is priceless, we cannot deny that this tree is particularly delicate. In fact, even the most resistant varieties suffer from attacks of fungal diseases such as:
Peach Scab: Peach scab is also known as “freckles,” and is caused by the fungus Cladosporium Carpophilum. The symptoms on the skin of the fruit are cracks and small dark spots, usually on the side that is exposed to the sun. This fungus can also infect the twigs and the leaves at the same time. A peach with scab disease is perfectly safe to eat once peeled.
Prevention & Treatment: It is a common disease, and most varieties are susceptible to scab. Cool, wet winters make optimal conditions for the spreading of the infection. Prevention, as usual, is the best cure. Prune the tree to minimize contamination and allow good air circulation and sunlight. Keep an eye to spot damaged fruits. Use a fungicide sprays every 10 days from the time the petals fall to 40 days before harvest.
Bacterial Spot: This disease is also known as bacteriosis or shothole and is caused by the Bacterium Xanthomonas Campestris pv. pruni. It affects peaches, nectarines, apricot, and plums. The signs of a tree affected by bacterial spot is when you see purple-brown spots on the foliage, followed by the center falling out, giving the leaves a “shothole” appearance. This will cause the leaves to turn yellow and drop.When a peach tree suffers from a bacterial spot, it will end up losing its fruit.
Prevention and treatment: The best way to prevent this disease is to plant a cultivar that is resistant to this fungus.A proper pruning will also help to keep the air circulating, as well as regular fertilization and watering. Be aware that too much nitrogen can aggravate the disease. To treat the disease, spray with a baking soda solution. You can prepare the solution as follows:1 tablespoon of baking soda2 1/2 tablespoons of vegetable oil, 1 teaspoon of Castile soap, Mix everything with one gallon of water, You could add neem oil, however, be aware that bees and other beneficial insects may suffer from that. Before application, spray only on a small part of the tree and see how it reacts. If there is no reaction the next day, spray the whole tree and repeat every two weeks.An alternative to the baking soda spray are copper-based products to be applied weekly, at the first sign of infection.
Brown Rot Brown rot is a fungal disease that commonly affects fruit trees like peaches and cherries. This disease is due to the fungus Monolinia Fructicola. The first symptoms of the disease are noticeable in the spring: the affected fruit has small spots of rot, which quickly develop and get bigger. The rotted fruit grows grey spores that end up covering the fruit surface and causes the fruit to mummify. To prevent this disease, you can use the same preventive measures as the one used for the leaf curl infestation.
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