Boxelder bug adult. Note the red-orange wing margins and red eyes. Photo by Joseph Berger, www.ipmimages.org.
Most people can easily recognize boxelder bug adults in urban areas, particularly on maple and ash trees. But the nymphs are bright orange or red, and can be confused with other insects.
Boxelder bug nymphs sort of look like big, red aphids. Eventually the nymphs will develop dark wing pads. Photo by Whitney Cranshaw, www.ipmimages.org.
Boxelder bug nymphs and adults prefer to feed on boxelder seed pods, but they have been found on many different plants this year. They rarely damage ornamental trees and are not a concern to field crops. Sometimes the adults can become nuisance pests in the fall when they try to overwinter in human structures. I suspect they will be an issue this fall based on our summer numbers.
Here is a mixture of boxelder bug life stages. Photo by William M. Ciesla, Forest Health Management, www.ipmimages.org.