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Speckled and spotted but still tasty

Whether you are harvesting from a backyard apple tree or visiting a local orchard, you are likely to find apples that are less than perfect at picking. Don't be dissuaded by appearances. Many of these apples are still quite edible as well as tasty.

There are several different fungal pathogens that infect apple fruit. Diagnosing apple disease problems now can help you make management decisions to reduce disease problems in the future and will help you decide which apples to eat and which to compost.
apple fruit with black raised corky spots
Apple scab infected apple
Photo: M. Grabowski, UMN Extension

Is it apple scab?

The most common disease of apples in Minnesota is apple scab. Fruit can become infected with the apple scab fungus throughout the growing season. Infections are rough corky spots on the surface of the fruit that are tan to black in color. Scab spots may be small and round or many spots may merge together to form large rough patches on the fruit.

The apple scab fungus does not rot the fruit but if infection occurs when the fruit is young and still growing, fruit may become distorted and cracked. If this occurs, other bacteria and fungi may move in and rot the fruit. Discard severely distorted or rotten fruit. Apples that have an intact skin but have some apple scab infection are edible. They can be eaten fresh or peeled and used for cooking.
apple with a cluster tiny black dots and larger green gray spots
Flyspeck and sooty mold on apple
M. Grabowski, UMN Extension 

What are the black dots and greenish-gray smudges?

Fly speck and sooty mold are fungal diseases that develop on the waxy covering of the fruit but do not infect the fruit itself. Flyspeck looks like a cluster of small black dots. Sooty mold looks looks like a small green gray smudge. These fungi never infect the living cells of the apple fruit and will not result in rot. They are purely a cosmetic condition.

Fruit with fly speck and sooty mold are edible. Sooty mold can sometimes be washed off although fly speck is more persistent.
end of an apple fruit with a brown rotten area
Black rot on apple
Photo: Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org

Spots of rotting...can I eat the apple anyway?

Black rot causes more significant damage to the apple harvest because the black rot fungus causes rot of the fruit in addition to discoloration of the apple skin. Apples infected with black rot are firm but have one to a few large brown round areas on the skin. When the apple is cut in half, brown discoloration of the fruit can be seen extending from the skin all the way to the core.

Apples that have extensive rot should be composted. If only a small area of the fruit is rotted, this area can be cut out and the remaining healthy fruit can be eaten. Apples with any signs of black rot should not be stored.

Learn more about how to manage apple diseases in the home apple orchard from the UMN Apple Pest Management guide.

Author: M. Grabowski, UMN Extension


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