The Black Blister Beetle is a slender, entirely black beetle frequently found in large aggregations on goldenrod and other composite flowers in late summer. Like all blister beetles, it contains cantharidin in its hemolymph, which blisters skin if the beetle is crushed. Horses can be fatally poisoned if they consume large numbers in hay.
Best time to see a Black Blister Beetle
The best time to see a Black Blister Beetle is August–September, when about 62% of U.S. sightings happen, based on 1,664 research-grade iNaturalist observations.
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Recent Black Blister Beetle sightings near you
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