Odd Colored Spots on Tomatoes Mark Past Stinkbug Feeding

Stinkbug on Tomato. Photo: David Riley, The University of GA, www.forestryimages.org.

MANHATTAN, Kan. – When tomatoes on the vine develop white, pink or yellow-gold spots, the likely cause is stinkbugs, according to a Kansas State University horticulturist.

Stinkbugs are the skunks of the insect world. They're shield-shaped, not striped. But, like skunks, they emit a foul odor when disturbed, said Ward Upham, who coordinates K-State Research and Extension's Master Gardener program.

"A stinkbug injures fruit when it uses its mouthparts to probe for food. That not only affects the tomato's color development but also causes a whitish ‘callous' to develop under the skin at the wound site," Upham said.

Typically, the exterior result is an off-color, cloudy spot. If stinkbugs are feeding heavily, however, the entire tomato may develop a gold hue, with pinprick-size puncture wounds in the middle of each of the overlapping spots, he said.

"Unfortunately, stinkbug control is basically impossible. By the time you notice the spots, the stinkbugs usually are gone," Upham added.

"Fortunately, though, the affected tomatoes are safe to eat."