Southern gardeners often notice these strikingly marked bugs around their home and landscape in such high numbers that they become concerned. “There are just so many of these things that they have to be damaging something.” However, bordered plant bugs, a.k.a. largus bugs, are not serious pests of turf, landscape plants, vegetables, or fruit trees, and they rarely cause significant problems as home invaders. Instead, they feed on a variety of weeds, seeds, and shoots of hardwood trees as well as scavenging on animal feces and dead insects. Large numbers are often seen on the trunks of pine trees, but they cause no apparent damage to pines either. Occasionally, a few bordered plant bugs are seen feeding on blueberries, blackberries, or other edible plants, but in general, these bugs are not pests. Compared to most pest insect species, relatively little is known about the biology of bordered plant bugs, simply because they have never been considered economically important.
Adult bordered plant bugs are about 5/8 inches long and are matte gray to black with distinctive orange borders around the edges of their wings and across the front portion of the back. The nymphs are shiny black to steel-blue, and older nymphs usually have a distinctive orange spot in the center of their back. Nymphs are sometimes seen in large clusters. Like many true bugs, both adults and nymphs have an offensive odor/taste that helps protect them from potential predators. Be aware that adults of some species of assassin bugs look a lot like adult bordered plant bugs, but assassin bugs have a painful bite. Actually, most any insect with piercing sucking mouthparts can potentially bite, but the plant feeders rarely do so.
Blake Layton, Extension Entomology Specialist, Mississippi State University Extension Service. The information given here is for educational purposes only. Always read and follow current label directions. Specific commercial products are mentioned as examples only and reference to specific products or trade names is made with the understanding that no discrimination is intended to other products that may also be suitable and appropriately labeled.
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