Green apples with apple scab on a branch

3 of the Most Common Apple Tree Diseases (and How to Prevent Them)

One of the most frustrating things about being a gardener is dealing with pests and diseases. While there are plenty of products on the market that can help, it’s always best to try and prevent problems before they start.

So, in this post, we’re going to take a look at three of the most common apple tree diseases and what you can do to prevent them.

Apple scab

Apple scab is caused by a fungus that attacks the leaves and fruit of apple trees.

Symptoms include small, dark spots on the leaves, which can eventually lead to defoliation. In severe cases, apples will develop scabby wounds.

Close-up of apples infected by apple scab - also know as Venturia inaequalis.
Apple scab

To prevent apple scab, make sure to thin out your trees to improve air circulation. You should also remove any fallen leaves or fruit from around the base of the tree.

Cedar-apple rust

Cedar-apple rust is another fungal disease that affects apple trees.

This one is distinguished by the orange or yellowish-orange galls that form on the leaves of cedar trees in late spring. These galls eventually burst open, releasing spores that infect nearby apple trees.

Cedar-apple rust disease visible on apples and leaves on crabapple tree.
Cedar-apple rust

Symptoms include small, round lesions on the leaves, which can eventually lead to defoliation.

To prevent cedar-apple rust, make sure to plant your trees in well-drained soil and avoid overhead watering.

Powdery mildew

Powdery mildew is a type of fungus that affects a wide range of plants, including apple trees. It’s characterized by a white or gray powdery substance that appears on the leaves and stems of affected plants.

Hands and scissors removing leaves on apple tree infected by the fungus disease powdery mildew.
Powdery mildew

Left untreated, powdery mildew can cause leaf loss and fruit damage. To prevent powdery mildew, make sure to plant your trees in well-drained soil and avoid overhead watering.

Conclusion

As you can see, there are a number of different diseases that can affect apple trees. However, by taking some simple preventive measures, you can reduce the chances of your trees becoming infected. And if worst comes to worst, there are always fungicides available to help treat affected trees.