Kudzu Bug

What it does

Kudzu bugs feed by sucking sap from legumes and cluster in large aggregations. In spring and fall they mass on sunny, light-colored surfaces, including house siding, cars, and around windows, and slip indoors through gaps to overwinter, much like stink bugs and boxelder bugs. When disturbed or crushed they release a foul, staining defensive secretion.

Where it lives

The kudzu bug's main wild host is the invasive kudzu vine, but it also infests soybean fields and garden beans. Native to Asia, it became established across the Southeast and Gulf region after 2009. Adults seek overwintering shelter on and inside homes and other structures, especially light-colored walls warmed by the sun.

How it breeds

There are usually two generations a year. Overwintered adults emerge in spring to feed and lay barrel-shaped eggs in rows on host plants, often beside small brown deposits of symbiotic gut bacteria the nymphs need. Nymphs are fuzzy and greenish, maturing over several weeks. The fall generation seeks shelter to overwinter as adults.

What it eats

Kudzu bugs feed on the sap of legumes: kudzu, soybeans, and garden beans such as snap and lima beans. Heavy feeding reduces soybean yield and can stunt garden beans. They do not chew leaves or feed on stored food, and they eat nothing indoors while overwintering.

Identification

Adults are small, about an eighth to a quarter inch, olive-green to brownish, with a distinctive squared-off, boxy body unlike the shield shape of typical stink bugs. Nymphs are greenish and hairy. Their habit of massing on light-colored walls in spring and fall, plus the odor when crushed, helps confirm them.

Signs of an infestation

• Clusters of small green boxy bugs on light-colored siding
• Bugs gathering around windows and doors in spring and fall
• A foul odor and greenish stain when they are crushed
• Bugs slipping indoors to overwinter in wall voids
• Feeding damage and reduced vigor on beans and soybeans

Prevention tips

• Seal cracks, gaps, and utility openings and add door sweeps before fall
• Repair window screens and vents to block entry
• Vacuum indoor bugs and empty the bag, rather than crushing them
• Reduce kudzu and weedy legumes near the home where practical
• Treat exterior gathering sites with a perimeter insecticide in early fall if needed

Professional solutions

Kudzu bugs are mainly a nuisance invader indoors and a crop pest outdoors. For homes, exclusion and vacuuming are the primary tools; a pest professional can apply an exterior perimeter treatment to gathering sites in fall. In gardens and on soybeans, well-timed insecticide sprays may be warranted for heavy infestations, following the product label.