Signs That Stink Bugs Are Damaging Your Tomato Plants (& The Best Way To Prevent It)

Tomato gardeners know the heartbreak of watching healthy fruit turn spotty, distorted, or sunken seemingly overnight. Learning how to prevent common tomato diseases is an important lesson for home gardening; learning about pest damage is just as important.  While several pests can cause damage to ripening tomatoes, stink bugs are often the sneaky culprit behind those yellowish blotches and hard, white spots just under the skin. These shield-shaped insects feed by piercing the fruit and sucking out its juices, leaving behind scars and internal damage that ruins both appearance and flavor. 

The brown marmorated stink bug is the most common in the United States, but the native green and brown stink bugs can also wreak havoc in gardens. The damage isn't always obvious right away, either. Many gardeners don't notice the signs until harvest. By then, it's often too late to salvage much of the fruit. Although the fruit is safe to eat, the damage creates light-colored, cloudy spots or yellow pinprick marks on the fruit's surface. Beneath the skin, the flesh is dry, spongy, and pale. These areas may become corky over time, making your tomatoes unappetizing and unmarketable. The damage typically starts at the top of the fruit near the stem and spreads downward.  Early identification is the first step to controlling stink bug issues in your garden, and the way to do that is to spot the stink bug insect as well as their eggs and nymphs before they become a widespread problem. Doing so will give you a head start on managing them before they cause too much trouble. 

Getting rid of stink bugs is a common problem for gardeners every year. There is no perfect answer, but prevention is certainly the best defense. Stink bugs spend the winter in leaf litter, woodpiles, and garden debris, so cleaning up your beds in the fall and rotating crops yearly can help reduce spring populations. During the growing season, use row covers to keep bugs off of your plants, especially when fruits are first setting. Be sure to remove the covers when the flowers open so pollinators can access the blooms. 

Other eco-friendly ways to keep stink bugs out of your garden include attracting beneficial predators like parasitic wasps, birds, and spiders, which can help keep stink bugs in check. Companion planting with nectar-rich flowers such as dill (Anethum L.) and parsley (Petroselinum crispum) supports these natural allies. Planting a crop of sunflowers to attract the stink bugs is also helpful. Hand-picking stink bugs early in the morning when they are sluggish or knocking them into soapy water is another effective way to prevent a heavy infestation. Avoid using broad-spectrum insecticides, which can harm helpful insects. Insect traps also don't seem to be as effective against stink bugs. Instead, focus on building biodiversity and staying vigilant. With consistent monitoring and a little preventative planning, your tomatoes can stay stink bug-free all season long.