Why Are There Spots On Your Tree's Apples?

Growing apples can be a lot of fun, but it can also be fraught with many challenges. One of the most frustrating things is when you're about to harvest your apples and realize they have developed spots! Spots on apples are generally caused by one of the three following diseases, and by figuring out which is to blame for your issues, you can determine how to best treat it.

Are your spots brown and warty?

Brown, scabby, warty spots are typically caused by a disease called apple scab. Sometimes these spots may be small enough that you're still able to eat and use the fruit. Other times, they can be the size of quarters and extend partially into the apples' flesh, making them undesirable to eat.

There's little you can do about your current fruit crop if it already has apple scab. However, you can protect next year's crop by cleaning up any fallen apples and leaves in the fall. This helps keep the tree from becoming re-infected by fungal spores the next spring. You should also have your trees sprayed with fungicides throughout the growing season –as often as every 10 – 14 days when it is rainy.

Are the spots yellow and sprawling like a spider web?

Spots of this variety are caused by a disease called powdery mildew disease. You're likely to also notice a powdery residue on the tree's leaves and small shoots. Powdery mildew disease is not very serious, and you can still eat apples with these minor spots.

You can reduce your chances of powdery mildew disease the following year by having heavily infected branches removed in the fall by a skilled tree care expert. Often, treating the ends of shoots with fungicides will help protect against the disease, too.  Spraying the apple trees with fungicides before the blooms emerge is also essential – many growers wait too long.

Are the spots large and essentially rotten?

If your apples appear to essentially be rotting on the trees, then a disease known as black rot is to blame. If you look closely, you will probably also notice yellow, bullseye-like spots on the leaves.  There is no saving fruit that is affected by black rot.

You may be able to protect the next year's crop by acting promptly. A tree care expert should survey your tree for any cankers, which are "wounds" in the stem where the fungus thrives. By excising these cankers, your arborist removes the breeding grounds of the fungus and may relieve the tree of the infection.  Any fallen apples or leaves must also be cleared up to prevent spreading of the fungus.

If your apples have spots, do not stand idly by. By having your tree treated in the proper manner, you can increase the chances of next year's crop turning out healthier. Contact a local tree company, like All Season Tree Service, for more information.