Stink bugs are the garden pest that gardeners notice with their nose as much as with their eyes. Disturb one and it releases a sharp, unpleasant smell — a defence that gives the insect its name and makes handling them a memorable experience. They are also a serious pest of tomatoes, peppers, beans and fruit, piercing the skin and sucking the juices, leaving pale, corky spots and deformed fruit behind. They are not dangerous to people, but they are persistent, hard to control with sprays, and increasingly common in many regions.
This guide explains how to identify stink bugs, what damage they cause, and organic-first control in order — from inspection and hand-picking through to barriers and predators, with least-toxic options only as a last step. If the damage on your plants does not match, the pest identifier helper can help you compare, and our squash bugs guide covers a close relative.
How to identify stink bugs
An adult stink bug is a shield-shaped insect, about 12–17 mm long, with a broad, flat body, five-segmented antennae and a distinctive triangular shield on its back. The most common species in many gardens is the brown marmorated stink bug, which is mottled brown with white bands on the antennae and legs, but there are green, brown and grey species too, and the nymphs — the young — are smaller, rounder and often brightly coloured with red, orange or black markings. The nymphs go through five stages before becoming adults, and each stage looks slightly different.
The smell is the giveaway: disturb a stink bug and it releases a pungent, cilantro-like odour from glands on its body. The eggs are laid in neat clusters of small, barrel-shaped eggs on the underside of leaves, usually in rows of about 28. If you find a neat cluster of pale green or white eggs on a leaf underside, check the plant for stink bugs.
Lifecycle in general terms
There is usually one generation a year in cooler climates, sometimes two where summers are long and warm. Adults overwinter in sheltered places — in houses, sheds, under bark and in leaf litter — and emerge in spring to feed and mate. Females lay eggs on the undersides of leaves through the summer, and the nymphs feed and grow through five stages before becoming adults in late summer. The new adults feed heavily in autumn, then seek shelter for winter.
Because the adults overwinter in buildings, they are also a household nuisance in autumn, when they gather on sunny walls and slip indoors through gaps. Sealing gaps in the house in late summer reduces the indoor problem, and it is worth doing even if the garden problem is small.
Damage signs
Stink bugs feed by piercing the plant with a needle-like mouthpart and sucking the sap, and the damage shows as pale, corky spots on the fruit, often with a small dark puncture mark in the centre. On tomatoes, the feeding causes cloudy white or yellow spots under the skin, and the fruit may be deformed or fail to ripen properly. On peppers, the fruit shows pale, sunken spots. On beans and peas, the pods are shrivelled and the seeds inside are pitted. On fruit trees, the fruit is dimpled and corky, and on young shoots the feeding can cause wilting and dieback.
The damage is often worse than it looks, because the puncture wounds let in fungi and bacteria, and the fruit rots from the feeding site. If your tomatoes have cloudy white spots under the skin and you find shield-shaped insects on the plant, stink bugs are the likely cause.
Organic-first control, in order
1. Inspect first. Check the undersides of leaves for egg clusters and the plants for nymphs and adults, especially on tomatoes, peppers, beans and fruit. Look for the pale feeding spots on the fruit. Note which plants are affected and how many bugs there are — a few bugs on a large plant need little action, while a heavy population on young fruit does.
2. Hand-pick. This is the most effective control for a home garden. Knock the bugs off the plant into a bucket of soapy water — do it gently, since crushing them releases the smell, and wear gloves if you are sensitive to it. Check the leaf undersides for egg clusters and scrape them off into the bucket. Do this in the morning, when the bugs are sluggish, and repeat every few days through the season.
3. Barriers. Fine insect mesh or row cover over the most vulnerable plants, put in place before the bugs arrive, keeps them off entirely. This is the most reliable control for tomatoes and peppers, though it needs to be removed or opened for pollination — or the plants need hand-pollinating. For fruit trees, netting over the tree before the fruit ripens protects the crop. Seal gaps in the house in late summer to keep the overwintering adults out.
4. Traps. Light traps and pheromone traps catch some stink bugs and tell you when they are active, but they will not control a population on their own, and pheromone traps can attract bugs from a wide area. If you use them, place them well away from the plants you want to protect. A simple trap — a bucket of soapy water under a light at night — catches some adults, but it is a supplement to hand-picking, not a replacement.
5. Beneficial insects and birds. Stink bugs have few effective predators in many regions, because their smell deters birds and other insects, but parasitic wasps do attack their eggs, and some birds and spiders eat the nymphs. Encourage parasitic wasps by planting small-flowered herbs and flowers nearby, and avoid broad-spectrum sprays, which kill the wasps. Do not rely on predators alone for this pest — hand-picking and barriers matter more.
6. Least-toxic options last. Insecticidal soap and neem oil sprayed directly onto nymphs can kill them, but they have little effect on adults, which are protected by their hard shell, and they need thorough coverage and reapplying. Kaolin clay sprayed on the fruit can deter feeding by coating the surface, though it leaves a white residue that needs washing off. Avoid broad-spectrum insecticides: they kill the parasitic wasps and other beneficial insects, and they rarely control stink bugs well, since the adults are hard to kill and new ones move in quickly. Always check your local extension service for products approved in your area.
Prevention
Prevention is about hygiene and timing. Clear away crop debris, weeds and leaf litter at the end of the season, since these provide shelter for overwintering adults. Rotate tomatoes, peppers and beans to fresh ground each year. Plant eggplant and other host plants where you can reach them easily for inspection. Seal gaps in the house and shed in late summer, before the adults seek shelter. Check the planting calendar for zone 6 in September for end-of-season clean-up timing. And plant a trap crop — sunflowers or millet at the edge of the garden can draw stink bugs away from the vegetables, where they can be hand-picked more easily.
Frequently asked questions
Are stink bugs dangerous to people or pets? No. They do not bite, sting or spread disease. The smell is unpleasant but harmless, and they are not poisonous if a pet eats one, though it may cause drooling or vomiting. They are a nuisance, not a health risk.
Why do stink bugs come indoors in autumn? They are looking for a sheltered place to overwinter. They gather on sunny walls and slip in through gaps around windows, doors and vents. Seal the gaps in late summer and the indoor problem will shrink.
Can I eat tomatoes with stink bug damage? Lightly damaged fruit can be eaten after cutting away the affected parts, but badly spotted or deformed fruit is best discarded. The feeding wounds let in rot, so use damaged fruit promptly rather than storing it.
Do stink bugs attack houseplants? Rarely. They prefer outdoor vegetables and fruit, though they may wander indoors in autumn and rest on houseplants. They do not usually feed on them.
What is the white stuff on my tomatoes? Cloudy white or yellow spots under the skin are the classic sign of stink bug feeding. The spots are corky tissue formed where the bug pierced the fruit. Check the plant for shield-shaped insects and look for egg clusters on the leaf undersides — and check your local extension service if you are unsure.
Stink bugs are a pest that rewards routine and persistence. Check the plants weekly, pick the bugs off into soapy water, scrape off the egg clusters, and cover the plants that matter most — and the damage will shrink to a level the garden can live with. For the close relative on squash, see our squash bugs guide, and for general help use the pest identifier helper.