As an apple lover, nothing is more disappointing than biting into a beautiful, ripe apple only to find dark blemishes marring the otherwise pristine fruit. These unsightly black spots on apple skin certainly diminish the appeal of the apple, but should they stop you from eating it altogether? Read on to learn what causes these spots, whether it’s still safe to eat spotted apples, and how to prevent black spots from plaguing your apple harvest in the future.
What Causes Black Spots on Apple Skin?
The main culprits behind black spots on apple skin are two fungal diseases – sooty blotch and flyspeck. Sooty blotch manifests as dark brown to black blotches ranging in size from a speck to over an inch wide. Flyspeck produces clusters of tiny, round black dots resembling fly droppings. These two fungi often strike in tandem, collectively marring apples’ skin.
While mainly a cosmetic issue, both fungi thrive in warm, humid conditions with prolonged wetness Infection typically occurs between August and September as apples near maturity. For this reason, sooty blotch and flyspeck are sometimes called the “summer diseases” of apples By spoiling apples’ appearance, these fungi can cause significant economic losses for apple growers.
Are Apples with Black Spots on Skin Safe to Eat?
The good news is that apples affected by sooty blotch and flyspeck are completely safe for consumption. Both fungi colonize only the fruit’s waxy cuticle, never penetrating the flesh. So while apples may look unappetizing with black splotches, the edible interior remains untouched.
You can safely eat apples with black spots on skin after peeling off the blemished skin. However, cutting away all the discolored areas can become tedious and waste a lot of apple flesh. A better solution is to simply wash the apples well before eating them.
Common Causes of Black Spots on Apple Skin
Sooty Blotch
Sooty blotch fungi colonize the surface of apples forming dark olive-brown to black blotches with indistinct edges. The blotches can range in size from a pinpoint to over 1 inch across. Warm humid weather promotes spread of this fungal disease during summer and fall. Prolonged wetness allows spores to germinate and infect fruits.
Flyspeck
Flyspeck also inhabits the fruit cuticle but produces clusters of small round black dots about the size of a pinhead. These dots resemble fly droppings, hence the name. Infection occurs in wet conditions above 60°F. Flyspeck fungi overwinter on twigs and infect fruits in summer.
Apple Scab
Apple scab fungus causes dark olive-green to black spots with feathery, irregular margins on leaves and fruits. Spots later turn brown/black and may coalesce. Wet spring weather encourages spread of spores. Scabby fruits become deformed, cracked, and more prone to rots.
Black Rot
Black rot infects fruits through injuries, emitting reddish-brown circles that expand into black sunken lesions. Centres become dry, wrinkled and tan. Fruits shrivel into “mummies” that persist on trees. Rainy weather with temperatures of 75-85°F promote black rot development.
Preventing Black Spots on Apple Skin
While sooty blotch, flyspeck, and other fungi won’t harm your health, it’s still desirable to avoid or minimize infestation Here are some tips to keep your apples free of black spots
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Prune apple trees to open the canopy. This promotes air circulation and allows fruits to dry quicker after rain/dew.
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Thin fruit clusters so apples aren’t touching. Close contact facilitates fungal spread.
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Remove fallen leaves/fruits, which harbor inoculum to reinfect next year’s crop.
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Apply fungicidal sprays containing captan, sulfur, or neem oil as fruits develop.
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Harvest apples as soon as they ripen. Left on the tree longer, they’re more vulnerable to infection.
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After picking, promptly refrigerate apples to slow fungal growth.
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Consume or preserve apples soon after harvest. Fresh apples don’t store well long-term.
With vigilance and preventative care, you can outsmart these fungal foes and enjoy applesauce, pie, and fresh snacks without the eyesore of black spots. Don’t let surface blemishes stop you from reaping the bounty of your apple harvest. Just take steps to prevent infection, and you’ll have bushels of picture-perfect apples this season and beyond.
Frequently Asked Questions
Can you eat apples with black spots on the skin?
Yes, apples with black spots are still safe to eat. Sooty blotch, flyspeck, and most other fungi only affect the fruit skin, not the edible flesh inside. Simply wash the apples well or peel away the blemished skin before eating.
What causes black spots on apple skin?
The most common culprits are fungal diseases like sooty blotch, flyspeck, apple scab, and black rot. They thrive in warm, humid weather with prolonged wetness. Other causes can include insect damage, sun scald, chemical burn, or impact injury.
How do you treat black spots on apple skin?
Prune trees for good air circulation. Thin fruit so apples aren’t touching. Remove fallen leaves/fruit with fungal spores. Apply fungicidal sprays containing sulfur, neem oil, or captan during summer. Harvest apples promptly when ripe. Refrigerate after picking to slow fungal growth.
How do you prevent black spots on apples?
Promote drying after wet periods. Remove debris harboring fungal spores. Use preventative fungicide sprays. Pick apples as soon as ripe. Avoid bruising/wounding fruits during harvest. Refrigerate apples promptly after picking. Eat or preserve harvested apples quickly.
What do black dots on apples mean?
Tiny black dots on apple skin are likely due to flyspeck fungus. Flyspeck colonizes the fruit cuticle and produces clusters of small round dots resembling fly droppings. Sooty blotch also causes smudgy black spots. Both mainly affect appearance. Apples are still safe to eat after peeling off blemished skin.
Can I eat apples with black spots on the skin?
Yes, apples with superficial black spots are safe for consumption. Sooty blotch, flyspeck, apple scab, and other fungal diseases only discolor the skin, not the flesh inside. Simply peel away visibly affected areas or wash the apples thoroughly before eating. The edible interior remains untouched.
With some diligent orchard care and preventative fungicide sprays, you can minimize unsightly black blemishes on apples. But even if some spots slip through, rest assured your harvest is still safe to enjoy. Don’t let a few small spots spoil your appetite for this delicious, versatile fall fruit.
How do these diseases survive and spread?
- Flyspeck and sooty blotch are caused by a complex of several different fungi.
- These fungi don’t cause fruit rot because they don’t infect the live cells of the fruit.
- They only grow in the waxy cuticle on the fruit surface, resulting in minor blemishes.
- The fungi overwinter on the fruit, stems, leaves and bark of many types of woody plants, including apples, pears and raspberries.
- Warm, humid weather encourages spore development and germination.
- Rain and wind spread the spores onto developing fruit.
- These diseases are more common in the southern half of Minnesota.
How to identify sooty blotch and flyspeck
- Smudges on the apple’s surface that are gray, green, brown or black.
- Smudges can be rubbed or washed off the fruit fairly easily.
Flyspeck on apple
- Clusters of tiny black dots on the apple’s surface.
- Dots can’t be easily cleaned off the fruit.