All About Apple Tree Diseases and How to Deal with Them

A freshly harvested apple right off the tree is undoubtedly enjoyable. However, you may have to exert a lot of effort for this fruity delight. After investing your time, money, energy, and work to produce a bountiful apple harvest, you wouldn’t want to lose your crops to disease. 

Apple tree diseases are common and can spread from one tree to another. Numerous conditions can infect your home garden; to best take care of your plant, read on about the different apple tree diseases below:

Viral Infections 

Flat Apple Disease

A virus that causes this disease is the cherry rasp leaf virus (CRLV), found in British Columbia and the Western US. CRLV can infect common orchard weeds, and dagger nematodes can spread it in cherry and apple trees. 

A sign that the disease has infiltrated your tree is with flattened fruit on both sides. Another symptom is when its leaves roll up from the midrib. As soon as you’ve noticed these symptoms, remove them immediately as there’s no known cure for these viruses. To Learn More about Flat Apple Disease, visit Gardener’s Path for a detailed explanation about how to detect these infections and how to deal with them in any way possible. 

Bacterial Infections 

Fire Blight 

A bacteria (Erwinia amylovora) can infect your tree by making its leaves look like someone set the tips on fire. The weather can spread rapidly, with rain and high humidity, especially in temperatures between 75 and 85°F.

Discontinue overhead irrigations when these conditions occur to reduce the amount of foliage moisture. You can also do pruning to control the disease. Spray copper with caution. Too much copper can damage the fruit or become resistant to an accumulation of bacteria. 

Crown Gall

Rhizobium rhizogenes is the causal agent of this condition; it changes the DNA of plants to produce a type of tumor, which is galls. The wooly apple aphids can also cause galls, but the difference between the two is that crown galls aren’t hidden in white cottony wax. Sadly, crown galls are usually fatal on apples.

Fungal and Water Mold Infections 

Apple Scab

A fungal disease called Venturia inaequalis manifests on the bottom of the leaves as small lesions in spring. The underside of the leaves spreads to the top and then to the fruit, where it looks like tiny brown scabs. 

This can be treated with the help of specialized tree service experts. You can get help from Tree Service Round Rock for tree care as they already to know what to do in such situations in order to save your plants and trees from this disease.

The fungus is difficult to control, and it makes it susceptible to diseases. However, you can prevent apple scab in early spring by spraying fungicides. Additionally, ensure that you’ve appropriately bagged the fruits and leaves from the previous year to prevent them from spreading. 

Powdery Mildew

A classic symptom is on the underside of its leaves; a white growth will accumulate. Then, as the infection worsens, it will stunt the growth, twigs, and leaves covered with specks, and the foliage will wilt.

Armillaria Root Rot

Infected trees have reduced growth of their terminal shoots, and their leaves turn purple earlier in the fall compared to healthier trees. Collapse of diseased trees during midsummer is a symptom you cannot miss. 

Physiological Disorders 

Cork Spot

If you’ve noticed that your crops seem like they have hail or insect damage, look more closely because these spots can progress to half-inch wide soft or corky spots. Cork spots result from a low soil pH that results in calcium deficiency. 

Cork spots are curable. Add lime if the pH of the soil is below 6.0. You can also spray calcium chloride to the apple tree every ten days up until you’ve harvested all your crops.


Sunscald is a result of being sunburned from the sun. An indication of this is when the skin of your fruit develops flushed or yellow areas, small yellow spots, to be exact. Then, while it’s still on the tree, it will turn dark. Avoid these when harvesting as it doesn’t store well. 

Dispose of apples you’ve detected that’s been sunscalded in the compost pile. It’s possible to manage this condition to avoid it in the future with proper training and pruning. Some farmers and gardeners use overhead irrigation, but it’s best to avoid this as it can lead to disease problems.

Bitter Pit 

Bitter pit takes place when calcium has been focused on the leaves, not the fruit. It’ll appear as small water-soaked lesions on your fruit for its first symptom. Gradually, it will look like bruises and eventually sunken. Although, after harvest, it won’t become bitter despite its signs. Bitter pits usually happen because of a dry and hot climate. 

Avoid using potassium and nitrogen fertilizer that much since it can lead the tree to grow an abundance of foliage. Instead, prevent bitter pit from happening by spraying it with calcium nitrate or calcium chloride over the summer.

Soggy Breakdown 

It happens when individuals store their fruit in a cool storage area to prolong its shelf life. However, a temperature that’s too long can have a chilling injury. Minimize this by maintaining the temperature of the storage area at 36ºF.


These apple tree diseases will challenge your skill as a gardener, but never fret because you’ve been guided with this article, and you now have the power of knowledge. However, with proper tree service training and education, you can overcome these issues. You can also get help from the tree experts, like The Local Tree Expert. Use the information above to tackle diseases that you might have with your tree.