It’s not uncommon for apple trees to experience yellow leaves with brown spots, but you might be wondering why the leaves are changing color and what you can do to fix it.
If you are dealing with apple leaves turning yellow with brown spots, then, this article is definitely for you.
A few days back when I was watering my apple trees, I noticed apple leaves are turning yellow with brown spots.
I had no clue why it was happening. So I searched google “Why apple leaves are turning yellow with brown spots?”
I found many gardeners are talking about this topic in some gardening forums. But there was no concrete information regarding this.
So I searched for more and after some research, I found a research paper based on this topic.
Why apple leaves are turning yellow with brown spots?
If your apple tree leaves turn yellow with brown spots, it’s mostly because of a common disease called Cedar Apple Rust. To get rid of it, remove the host trees, prune the infected branches and apply fungicides or sulfur weekly.
There are some other diseases like – Apple Scab, Fire Blight, Alternaria Blotch, Sooty Blotch, Flyspeck, Powdery Mildew, Bitter Rot, Black Rot, White Rot, Necrotic Leaf Blotch, Apple Chlorosis, Cork Spot, Frog Eye Leaf Spot, Phytophthora Rot, Crown Rot, Canker, Entomosporium Leaf Spot, etc.
Your apple tree leaves can turn yellow with brown spots because of poor drainage and extreme temperature too.
Disease-Causing Yellowing Apple Leaves With Brown Spots
Apple trees not only make your outdoor landscape beautiful but also are one of the healthiest fruits in the world. However, unfortunately, when apple trees are not growing in the ideal condition they can be susceptive to a wide range of diseases.
Let’s check out the common disease of apple trees –
Cedar Apple Rust
Cedar-apple rust is a commonly found disease of apple and crabapple. Gymnosporangium juniperi-virginianae, is the fungus that causes this disease. This fungus spends a phase of its life cycle as a parasite on Juniperus species, like- red cedar or ornamental juniper. To infect apple leaves, this fungus needs adequate moisture in a temperature range between 46 and 75 degrees Fahrenheit.
How To Identify Cedar Apple Rust
The apple tree leaves will become yellow and eventually turn orange-brown with a red border. These yellow or orange spots will develop approximately ¼ inch in diameter. In these spots, block dots will form in the center, with time. These colorful spots will be shown on the upper side of the leaves. On the lower side of the leaves, you will find a short fungus tube sticking out. In early spring, galls develop in the branch’s tips. These galls begin to swell up to 2-inches in diameter. They develop bright orange, jelly-like tubes.
How To Treat Cedar Apple Rust
Prevention of cedar-apple rust is not easy. Remove the host trees from apple trees. You need to prune all the infected leaves and branches to prevent infection in your apple orchard. Applying fungicides containing fenarimol or myclobutanil will be a help. Otherwise, you can weekly apply organic fungicide or sulfur to prevent the infection.
A fungus called Venturia inaequalis is the reason behind apple scabs. McIntosh, Cortland, and Macoun are the particular varieties that are mostly get affected by this disease. Apple scabs Infect apple trees in early May when green tissue emerges from the bud. The disease spreads all season with each rainfall.
How To Identify Apple Scab
The symptom of apple scabs is yellow and brown lesions on the leaves. These spots develop into dark, olive-brown spots on leaves and fruits. These spots can be quite large in size and able to cover most of the leaf’s surfaces. In case of severe infestations complete yellowing and dropping of all or large sections of leaves can occur.
How To Treat Apple Scabs
Clear all the fallen leaves of your apple trees to prevent infected fallen leaves from spreading spores to the fruit trees next spring. Prune all the infected branches. This prevents the foliage available to spread the fungus. Pruning encourages healthy circulation in the branches.
In spring, apply a commercial fungicide to your apple tree every two weeks when new shoots appear.
If you want to prevent Apple Scabs, planting disease-resistant varieties is the best way. There are many varieties of apple and crabapple trees, that are resistant or completely immune to apple scab.
Fira blight is the most serious and common disease of apple trees. It is caused by a bacteria called Erwinia amylovora. The USDA Cooperative Extension has a chart where you can see all the fire blight susceptive variants.
How To Identify Fire Blight
Fire Blight affects flowers first. It will cause infected flowers to turn black and die. Fire Blight can infect parts of the tree including blossoms, stems, leaves, and fruits. In spring, during wet weather conditions, you will find a milky liquid oozing from infected areas. This disease is most dangerous to the new shoots but can be spread all over the plant. In rain and high humidity, it can spread rapidly. These bacterias are most active when the temperature is more than 60-degree Fahrenheit.
How To Treat Fire Blight
You can spray copper to prevent fire blight, but too much copper can harm the fruits or make the bacteria resistant. In order to prevent fire blight, nothing can beat pruning. Prune all the branches, leaves, and flowers.
Alternaria Blotch is the most common disease of apple trees. It is caused by a fungal pathogen called Alternaria mali. Late spring to early summer is the time for this disease.
How To Identify Alternaria Blotch
Purplish to black spots will be shown on the leaves. The lesions will enlarge and become darker in color with time. The leaves will turn yellow and fall prematurely if the lesions appear in the petioles. Premature fruit drops can occur in case of severe defoliation in the apple tree.
How To Treat Alternaria Blotch
To prevent the spreading of the fungal spores, keep the surroundings of the apple tree clean from fallen leaves and plant debris.
Cut off all the infected leaves and branches. Spray neem oil solution every few days until the symptoms are completely gone. You can use commercial fungicides, including Flint 50WG, Luna Sensation, etc. Apply fungicides as per instructions written in the packet.
Sooty Blotch and Flyspeck
These two different types of the disease occur together on the same near-mature fruit. No known cultivar resistant to these two diseases has been found yet. Flyspeck is caused by Zygophiala jamaicensis fungi. All varieties are susceptive two these diseases but yellow varieties show severe symptoms.
How To Identify Sooty Blotch and Flyspeck
Both Flyspeck and sooty blotch grow on the surface of apples. They create blemishes on the apple’s surface. They do not harm the apple itself. Both diseases appear together. Late summer is the time of their development. Circular clusters of tiny, defined black dots are created by Flyspeck. Irregular, olive-green blemishes around the apple’s surface are formed in the case of Sooty Blotch.
How To Treat Sooty Blotch and Flyspeck
To prevent these you need to apply a fungicide application in mid to late July. In August apply the second application of fungicides. Prune and thin the apple trees. It will increase air circulation and dryness. These diseases tend to occur in shady areas of the orchard. Opening up the trees to air movement will help to control these diseases.
Powdery mildew will not kill your tree, but it can stunt the tree’s growth and hamper fruit production. This disease prefers hot, dry conditions. They spread during buds opening in the spring. The fungus overwinters inside infected buds, after bud opening in spring, powdery spores cover them. The wind spread the spores to infect new leaves, fruit, and shoots.
How To Identify Powdery Mildew
Gray-white powdery patches form on leaves due to powdery mildew. The growth of the tree stunts and the flowers produce no fruit. Leaves and shoots turn brown in mid-summer. Susceptible cultivars are Jonathan, Bonza, Jonagold, Elstar, Pink Lady, Lady William, and Gala.
How To Treat Powdery Mildew
If your tree is affected by the above symptoms, prune every shoot that is white and destroy them in the early spring. Make sure to disinfect your pruning shears. You can spray with sulfur or a fungicide in the early spring to get rid of powdery mildew.
Bitter Rot appears in mid to late summer. When the weather is warm and humid the fungus breaks out. They can cause severe damage to your apple orchard. Apples like Empire, Honeycrisp, Mclntosh, Sunrise, Paulared, and Jonagold are most susceptible to bitter rot.
How To Identify Bitter Rot
Small brown spots on the skin of the fruit will appear, these spots grow and darkens quickly. The fruit develops black spots. These black spots are the fruiting spores of the fungus. A sour-smelling rot develops in the fruits. If the infected fruit ripens, it will decay and dry up.
How To Treat Bitter Rot
To prevent bitter rot apply fungicides before winter sets up. Cut off infected fruit, dead wood, and any cankers formed in the wood tissue. According to Penn State Extension applying fungicides, every 10 to 14 days will be helpful at the time of harvest. If you apply fungicides more frequently under the preferred condition of bitter rot, it will be a big help to prevent them.
Black Rot is a fungal infection. It affects the fruit, branches, and foliage of affected trees. It can be managed by proper care and rarely needs to be treated with fungicide. Empire and Cortland are more susceptible to black rot than other cultivars.
How To Identify Black Rot
Black rot creates frog eye leaf spots, fruit rot, and cankers on branches. Infected leaves form spots that look like frog eyes with reddish edges and tan middles. Most commonly on the blossom end of the apple, large, brown, rotten spots develop. Despite the brown surface of the apple, the flesh of the apple remains firm. Fruits shrivel up and dry out.
How To Treat Black Rot
Black rot can be treated by pruning the affected parts of the tree. You need to prune 8 to 12 inches away from the lesions. After pruning, don’t forget to sanitize your tools between each cut. It will help you to avoid spreading the infection. You can use captan and sulfur products labeled for black rot control if you need them. Fungicides are not typically used to treat Black rots.
White rot is a fungal infection that is usually brought on by drought or fire blight. White rot can lead to a 50 percent loss of fruit. Golden Delicious, Empire, and Jersey Mac are more affected by white rot. It is a severe and frequent late-season disease that can affect apple trees.
How To Identify White Rot
Light brown cankers on fruit and branches will appear. On fruit, it causes large brown rotten spots.
How To Treat White Rot
Cut off shriveled, rotten apples and prune deadwood, typically fungicides are not required for its treatment. To save trees from experiencing stress Perform preventive measures. Remove fire-blighted wood and water trees during drought to decrease the stress on the trees.
Necrotic Leaf Blotch
Necrotic leaf blotch turns apple tree’s leaves yellow. This disease only affects golden delicious apples. Necrotic leaf blotch spreads in the warmer and wetter months of June and July like other diseases.
How To Identify Necrotic Leaf Blotch
Leaf blotching, yellowing affected leaves, and defoliation is the symptom of Narcotic leaf blotch. Defoliation can be severe,10%- 50% of the leaves can fall off. Irregular brown blotches, usually 0.5 to 1.5 centimeters in diameter appear on leaves. A large number of yellow leaves is a common symptom of narcotic leaf blotch.
How To Treat Necrotic Leaf Blotch
For treating Narcotic leaf blotch, Fungicides that contain zinc (Zn) ions are the most effective. Spray fungicides during the summer to have less necrotic leaf blotch.
Apple chlorosis occurs if there is a lack of iron in the soil. Water-soaked soil enhances the problem of apple chlorosis among apple trees.
How To Identify Apple Chlorosis
If you notice leaves are yellowing and die-off, then it might be apple chlorosis. In this disease, the yellowing starts just outside the leaf veins. The leaf becomes yellow with bright green veins. In severe cases, the leaf will turn pale, almost white.
How To Treat Apple Chlorosis
You need to maintain the soil pH to get rid of apple chlorosis. Apply foliar spray to the saturated soil every 10-14 days.
Cork spot is not a disease, it is a disorder of the tree’s physiology. An unappealing outside appearance and a corky texture form in the apple due to this condition. Cork Spots occur in fruits, which are low in calcium. An imbalance in potassium, magnesium, and calcium can cause cork spots too. This process normally starts in the early summer. It continues as the fruit grows and enlarges.
There is nothing much you can do to prevent this situation. You can add limestones to the soil every 3-5 after planting. You can spray calcium to reduce cork spots.
Apple Crown and Collar Rot
Crown rot is caused by fungi in the genus Phytophthora. It is a major cause of tree death in orchards. Heavy, poorly drained soils and certain rootstocks that are more susceptive can be affected by this disease.
The first symptom of this disease is delayed bud break, leaf discoloration, and twig dieback in spring.
With rootstock selection, orchard site selection, and horticulture, you can prevent apple crown and collar rot.
Entomosporium Leaf Spot
Entomosporium leaf spots are caused by the fungus Entomosporium mespili. Tiny, circular, often bright red spots on both surfaces of young expanding leaves are the first symptoms of Entomosporium leaf spot disease. On heavily diseased leaves you will find small spots that may coalesce to form large purple to maroon blotches.
Treatment of Entomosporium leaf spot depends on the use of cultural practices, resistant varieties, and applications of fungicides.
Other Reasons Of Apple Leaves Yellowing
Apart from the disease, there are some other reasons apple leaves turn yellow. Let’s discuss the other facts that are yellowing your apple leaves.
Seasonal or Natural Leaf Yellowing
Lack of Important Nutrients
Leaves will not grow properly if there is a shortage of nutrients. In lack of important nutrients, leaves will gradually yellow and fall off. The main nutrients that apple trees need are nitrogen, phosphorus, and potassium. However, a lack of nitrogen can cause leaves to yellow.
Poor Drainage System
Too much water can harm your favorite apple plant. The roots of your apple tree can rot. Clay is a bad medium for drainage, it often holds water.
Water your apple tree water when the top 2-4 inches of soil gets dry. If you let the soil slightly dry out, it will help aerate the roots. This can prevent mold from developing. However, if the drainage is not working well, the soil will be wet after several hours of watering.
Lack Of Water
If you are not watering your apple tree properly the leaves can turn yellow and dry out. If you have an automatic irrigation system, drippers can easily block up. Which can make your plant suffer from lack of water.
Apple trees can get yellow leaves due to a sudden change in weather. Yellow leaves can occur when the weather gradually gets too hot or cold.
As most apple trees like cold weather, getting yellow and brown leaves from extreme heat is common for them. This can happens if temperatures exceed 95ºF.
Apple Tree Care
If you are an apple grower, you need to take care of your apple trees very carefully during the growing season. To prevent fungus and other pests, pest control is very important.
Climate Considerations are very important in growing apple trees.
Most apple trees like to grow near water bodies. If your apple tree is in a pot you need to take care of it very carefully.
Let me give you some tips on how to take care of your apple plant –
- You need to water your apple plant daily.
- Refreshing mulch regularly is important, but don’t let it contact the trunk, it can rot.
- Using pest control in order to care for your plant properly will be a big help.
- You have to cut off misplaced buds to avoid misplaced brunches.
- You need to train your apple trees to carry a strong frame. Otherwise, they won’t be able to carry heavy apple crops.
- If you want to slow its growth, you have to bend a stem almost horizontally for a few weeks. It will help grow branches and fruits.
- Pruning is very important for avoiding fungus or bacteria attacks. Prune your mature plant when it’s completely dormant.
- Remove the weak twigs to maintain the healthy growth of your apple plant.
- It’s better for the apple plant to shorten the droopy stems.
- You need to remove the damaged or small fruits, soon after the fruit is set to get healthy fruits.
Wrapping Up- Apple Leaves Turning Yellow with Brown Spots
After all the discussion in this article about the diseases of apple trees, now you know the reason behind yellowing apple leaves with brown spots.
Apple leaves can turn yellow for many reasons.
Fungi or a lack of nutrients both can turn your apple leave yellow.
The pH of the soil and poor drainage, lack of water, or too much can also hamper your apple plant. There are many factors that can cause your apple leaves to fall off.
All you need to do is take care of your apple plant, follow the appropriate treatment for the disease and prevent the infection from returning. Happy Gardening!