What you see: Sunken dark spots on an apple. The skin still appears smooth.
What it is: A number of issues can cause sunken areas on otherwise smooth apple skin, but if it looks like the image above, it’s likely stink bug damage.
Eat or toss: Peel or cut away the damaged areas and eat!
Apples with stink bug damage are still edible
If you see smooth, but discolored and dented spots on your apple, and if you peel the skin away and find a patch of brownish, corky apple flesh, odds are good that a stink bug got to your apple before you did.
And that’s OK. You can just cut around the damaged areas.
Stink bugs bite apples in a way that’s a little similar to how mosquitos bite humans. Except, instead of sucking the apple’s blood and making them itchy, stink bugs probe below the apples’ skin and then slurp up a customized apple sauce-like brew.
“These insects feed on the fruit by inserting their straw-like mouth parts and inserting some salivary enzymes to start breaking down the fruit tissue, then slurping it out,” explained Anna Wallis, fruit coordinator for New York State’s Integrated Pest Management Program.
Stink bugs leave smooth, slightly sunken spots on apples
The holes created by those straw-like mouth parts are so subtle they’re hard to see. But look closely, maybe with the help of a magnifying glass, and you’ll notice a bullseye dot in the middle of the spots (and if you don’t see a dot, read on for other possible explanations).
Because the insects’ feeding literally removes part of the apple, the bitten areas sink, even as the skin remains smooth. The peel’s discoloration likely comes from a combination of oxidation of the broken tissue and the natural color of the apple skin above it. The damage tends to be more dramatic if the stink bug snacks on younger apples, though stink bugs tend to do their most intensive apple feeding during the final few weeks of harvest, according to an article from the Michigan State University Extension. Stink bugs can nip and slurp any area of the apple, but may show a preference for the “shoulders,” the same article says. The bugs tend to stick to the trees on the outer edges of orchards.
The brown marmorated stink bug
The brown marmorated stink bug, an invasive insect with a body shaped like a knight’s shield, terrorizes crops so much that the U.S. Department of Agriculture helped fund a special organization dedicated to its demise. With experts from nearly 20 institutions, StopBMSB.org is a hub for work on the pest.
One thing growers can do to deter the bugs is to keep flowering plants away from their orchards, advises an article from the University of Missouri’s Integrated Pest Management Program. Blooms attract stink bugs, so removing vegetation under apple trees and nixing flowering weeds between orchard rows or in the ground cover can help.
Other potential causes of sunken spots on apples
Impacts from hail striking the fruit and a nutritional deficiency called bitter pit can also cause dented spots on apples. In those cases, you won’t see a telltale pinprick in the center of the spot.
Another possibility is damage from an apple maggot. Thanks to modern agriculture, it’s unusual to find a worm in an apple these days, but you might instead find a wound that resembles stink bug damage. That’s because apples are treated so that apple maggot eggs laid inside the apple (I know, so gross!) will never develop. So, rather than find a wiggler in your apple, you might find a brown spot near the surface–evidence of at attempted apple maggot that damaged the apple a little, but never moved past the egg stage. Icky, but as with stink bug damage, you can just cut around it.
SOURCES:
- Anna Wallis. Fruit Integrated Pest Management Coordinator for New York State Integrated Pest Management (Cornell AgriTech. Cornell University). Email correspondence
- Stink Bugs (Agriculture: Apple Pest Management Guidelines). University of California Agriculture and Natural Resources. Statewide Integrated Pest Management Program. Accessed March 2025.
- Brown Marmorated Stink Bug and Late-Season Apple Damage. Janet van Zoeren and Christelle Guédot. Wisconsin Fruit. University of Wisconsin Fruit Program. September 3, 2020. Accessed March 2025.
- Catfacing Injury on Apples and Peaches. Michele Warmund (University of Missouri Plant Science & Technology). Integrated Pest Management, University of MIssouri. May 29, 2018. Accessed March 2025.
- Look-a-like late season apple damage by bitter pit, brown marmorated stink bugs or apple maggot. Julianna Wilson, Wilson and Larry Gut (Michigan State University, Department of Entomology) and Amy Irish-Brown (Michigan State University Extension). Michigan State University Extension. September 2017. Accessed March 2025.
