Why Do Apple Tree Leaves Turn Black and What Can You Do?
Apple tree leaves can turn black for a variety of reasons. Often, these issues are linked to fungal, bacterial, or viral diseases. To tackle the problem, we usually treat the planting with fungicides, insecticides, or other remedies. However, some diseases are incurable, leaving you with no choice but to cut down the trees.
Why are there black spots on the apple tree leaves?
Black spots on apple tree leaves are often related to diseases. Some of them are treatable, especially at an early stage.
Others, unfortunately, are untreatable, so all you can do is remove the affected tree to protect the nearby plantings.
Bacterial Blight
If you see black spots on your apple tree leaves, it’s likely a sign of bacterial blight. This is an infectious and complex disease that is difficult to treat.
The leaves turn black at different times – early spring, at the beginning of the flowering phase, or even in the fall.
The spots quickly grow and merge together, after which the leaf becomes entirely black and dries up.
Interestingly, the leaves stay on the tree and don’t fall off. Gradually, the tree starts to shed its fruit and may even die.
Characteristic Symptoms
A telling sign is that not only the leaves turn black, but all other parts as well.
From afar, it might appear as if the apple tree was burned or struck by lightning. That’s why we call this disease bacterial blight.
Primary Treatment Measures
- Completely remove all shoots affected by the disease, capturing at least 2 inches (5 cm) of the healthy part.
- Treat the cuts with a weak solution of potassium permanganate or dust with wood charcoal powder.
- Carry out treatment with a powerful copper-containing fungicide.
- After the fall leaf drop, it’s essential to treat the entire tree with a concentrated (50%) urea solution.
For the treatment of fungal diseases. Here are the fungicides I recommend:
| Name of The Fungicide | Amount | Amount of Water |
| Bonide 811 Copper 4E Fungicide | 1-4 tablespoons (.05-2.0 fl oz) | 1 gallon of water |
| Garden Safe Brand Fungicide3 | 2 tablespoons (1 fl oz) | 1 gallon of water |
| Southern Ag – Liquid Copper Fungicide | 3-4 tablespoons | 1 gallon of water |
Attention!
If a significant part of the apple tree is affected by the blight, not only the leaves but also the skeletal branches have turned black, you’ll need to dig up and destroy the tree.
Scab
If the apple tree leaves are not only turning black but also curling, it indicates the development of a fungal disease known as scab.
First, brown oily spots appear on the leaves. Then they start to darken, after which the leaf curls and dries up.
The leaves then fall from the tree, which is the main distinction between scab and bacterial blight.
An affected tree may survive a few more years, but it will grow worse, negatively impacting the yield.
Therefore, it’s recommended to start treatment as soon as possible. Treat the plantings with fungicides.
Apply the spray several times per season at two-week intervals. The final treatment should take place at least 28 days before the fruit begins to appear.
Ring Spot
If the leaves initially cover with yellow spots, the cause may be ringspot disease.
After a while, the leaf surface begins to darken and expand. Both leaves and fruits form black spots – these are necrotic areas where plant tissues die.
Ring spot is a very dangerous viral disease. Its effects are noticeable in the first season:
- The tree grows poorly and is weakened;
- The shoots appear shortened;
- The leaves shrink and turn black;
- The yield drops.
If black spots on the apple tree leaves appear due to ring spot, it’s tough to treat the tree, as there are no medicines for this disease.
Therefore, we completely remove the affected shoots and treat the apple tree with immune-boosting agents, such as All-Natural Root Ruckus Liquid Compost.
Apple Tree Leaves Turning Black at the Edges and Tips
If the tips of the apple leaves are turning black, it could be due to disease or improper care. The main reasons are described below.
Nutrient Deficiency
If the leaves are turning black not only at the edges but also at the tips, one of the possible reasons is a deficiency of manganese and magnesium compounds.
This non-infectious disease is known as chlorosis. A characteristic sign is the leaf paling, losing its saturated green color.
To replenish the deficiency, I recommended to spray the roots with such solutions as:
- Magnesium sulfate (0.03%);
- Manganese sulfate (0.05%);
A root feeding is required using:
- Calcium Carbonate Limestone Powder
- Magnesium nitrate (0.1%).
It’s better to alternate treatments at intervals of 10-15 days. Three feedings are enough for complete recovery.
Monitor the condition of the apple tree – as soon as the black leaves stop appearing, stop adding fertilizers. Remember, overfeeding is worse than underfeeding.
Root System Burn
If the tree’s young leaves are turning black, it might be due to a root burn.
This happens due to improper care when fresh, undecomposed manure is given to apple trees, or they are watered with a urea solution immediately after planting.
In such cases, it’s recommended to completely replace the surface layer of the soil. You should work carefully to avoid damaging the plant’s roots.
Mosaic Virus
The leaves can turn black due to a viral infectious disease known as the mosaic. At first, bright yellow stripes and spots appear on them, after which they start to turn black and die off.
The affected foliage falls off (even in summer). The tree noticeably grows worse, and the yield can fall by half. If the infection is left unattended, fruiting will cease entirely.
Heads up! There’s no adequate treatment for mosaic virus. You’ll have to chop down and burn the infected tree.
Why Is There a Black Coating on the Leaves?
If a black coating appears on the apple tree leaves, it indicates the development of an infectious disease. The cause can also be linked to dangerous pests – aphids or spider mites.
Black Spot Disease
Black spots on leaves is a fungal disease that can cause serious damage to apple trees.
It causes red or reddish-brown spots to appear on the leaves, which then merge to form dark patches. In advanced cases, a black coating resembling soot may appear.
The leaf blades are not only covered on the outside, but also on the inside, causing them to dry out and fall off. This can lead to the tree becoming bare by mid-summer.
If you see any signs of Apple Scab, it is important to act quickly. Cut off and remove all affected shoots and other parts of the tree.
Treat the healthy parts with a copper-containing fungicide. Be sure to smear the cuts with garden pruning sealer. Repeat the treatment several times, every 3 weeks or so.
Sooty Mold
A black dense mold that can sometimes appear on apple trees. It is not a disease itself, but a secondary infection that occurs when the tree is infested with pests such as spider mites or aphids.
The pests excrete a sugary substance called honeydew, which provides a food source for the mold.
To control Sooty Mold, it is important to control the pest infestation. You can do this by washing the leaves with a strong stream of water, or by using insecticidal soap or neem oil.
You can also make your own copper-soap solution to control Apple Scab and Sooty Mold.
To do this, dissolve 5g (0.176 oz) of copper sulfate and 150ml (5.07 fl oz) of liquid soap in 10 liters (2.64 gallons) of water. If you don’t have liquid soap, you can use bar soap, grated.
Be sure to wear gloves and eye protection when handling copper sulfate. It is a toxic substance and can cause skin and eye irritation.
Apple Leaves Turning Black After Treatment
If you’ve noticed your apple tree’s leaves turning black and curling after treating it with a fungicide or other substance, it could be because you used too much of the fungicide or you applied it at the wrong time.
Copper-based products are especially dangerous if you use too much. That’s why it’s important to carefully read the instructions when you’re mixing the solution.
Don’t deviate from the dosage, even a little bit, especially if you’re spraying in hot weather.
Pro Tip: If you notice black leaves on a young apple tree after treating it with copper-based substances, you can help the tree by shading it for a couple of weeks.
What to Do if Young Apple Trees’ Leaves Are Turning Black
If you’re dealing with black leaves on young saplings, it could be because you’re not watering them enough.
Apple trees are typically watered several times a season, but young saplings should be watered at least once a week. If there’s a drought, water them twice a week.
Too much moisture can also be harmful, so it’s important to check the soil condition. The top layer of soil should only be slightly moist.
Sometimes, the leaves of young apple trees turn black because they’re infected with bacterial, fungal, or viral diseases.
This is often the case when saplings are purchased from shady sellers. It’s best to buy your saplings from a nursery or other reputable source.
Preventive Measures
To prevent apple tree diseases and other causes of leaf blackening, it’s important to adhere to certain rules.
These are crucial at all stages, from buying the sapling to caring for the grown tree.
Key preventive measures include regular fertilizing, moderate watering, regular treatments, and pruning.
Choosing the Right Sapling
To avoid blackening leaves, it’s best to buy apple tree saplings from nurseries or other reputable stores.
Check out the plant carefully when buying. All shoots and leaves should be healthy, free of spots, stains, and other abnormalities. If possible, inspect the root system too.
Heads Up! When planting, be sure to leave enough space between saplings. If they’re too closely packed, infections can easily spread from one tree to another.
Keeping the Orchard Clean
You need to regularly inspect tree trunk circles and do the weeding. It’s also essential to remove mosses and lichens that settle on the trunks, branches, and parasitize on the trees.
In the fall, after pruning and leaf fall, thoroughly remove all plant residues and burn them.
Dig over the soil in the root area, and you can whitewash (white lime-based paint) the trunk at the same time. It’s a good idea to repeat this procedure in early spring.
Pruning
To keep apple tree leaves from turning black, timely pruning is necessary. In early spring, remove dry, weakened, and withered branches. In the fall, you can do the shaping pruning.
Treat the cuts with garden varnish, a fungicide solution, or dust them with wood charcoal powder.
Fertilizing
In the spring, till the soil around the trunk and incorporate manure or compost into it.
During the fruit formation period, provide superphosphate and potassium. In the fall, apply a comprehensive fertilizer, like Espoma Organic Tree-Tone.
Preventive Treatments
You need to do this at different stages. The exact plan depends on the choice of specific treatments.
For instance, spray with a Bordeaux mixture as follows:
- Early spring – 3% solution;
- After bud break – 1% solution;
- After harvest – 1% solution.
To prevent the appearance of black leaves, spray the apple trees with iron sulfate:
- Early spring – 5% solution;
- After bud break and after flowering ends – 1% solution.
Here’s my treatment schedule using copper sulfate:
- In March-April – 3% solution;
- After bud break – 1% solution;
- After flowering ends – 1% solution.
Key Takeaways
- Regular preventative measures, including the right choice of sapling, timely pruning, adequate fertilizing, and preventive treatments can help keep apple trees healthy and their leaves from turning black.
- The blackening of apple leaves can be due to numerous diseases like bacterial blight, scab, ring spot, and mosaic virus, as well as conditions related to nutrient deficiencies or improper care.
- For non-infectious conditions causing leaf blackening, such as nutrient deficiencies, it’s important to feed the trees with appropriate nutrients such as magnesium and manganese sulfate and monitor for recovery.
- In cases of infectious diseases causing leaf blackening, some are treatable using fungicides, insecticides, or other treatments, while others, like ring spot and mosaic virus, require the removal of the tree due to the lack of adequate treatments.
- For young apple trees experiencing leaf blackening, proper watering habits are crucial, along with ensuring they are obtained from reputable sources to avoid early infection.
