Voracious Stink Bugs Pose Threat To MD Fruit Trees And Gardens

MARYLAND — Brown marmorated stink bugs are on the move in gardens in Maryland, though you may not see the damage left behind by the shield-shaped menace until July or August.

Found in Maryland and 46 others, stink bugs are an enemy to fruit growers. Stinkbugs can cause severe damage in their 50-day lifespan with their piercing, sucking mouthparts — tiny shields about a half-inch long and wide, which they curiously tuck between their legs when they’re not feeding.

Their preferred diet comes from fruit orchards, ornamental trees and garden vegetables like tomatoes, peppers and sweet corn, according to the Stop the Brown Marmorated Stink Bug strike force, a team of 50 researchers from 18 land-grant universities closely tracking the migration of the invasive, fast-moving pest.

When stink bugs feed on crops, damage can include everything from bruises and blemishes to aborted sweet corn kernels to a change in the sugar levels in some fruits. These voracious eaters have caused severe agricultural and nuisance damage in just under a dozen states, mainly those in the mid-Atlantic region, but also in Michigan and Oregon. Another 15 states report agricultural and nuisance problems.

In Maryland, surveillance by Stop the Brown Marmorated Stink Bug shows that high levels of stink bugs could pose a severe threat to the state's agricultural economy in the absence of control measures. Likewise, widespread infestations of homes and offices in the fall and winter could become a nuisance.

Related: Insects Waking Up Now In MD: Spotted Lanternflies, Stink Bugs, Bees

Right now, stink bugs are in various stages of development. Adult stink bugs are busy reproducing and laying eggs — light green and barrel-shaped, you’ll find them attached side-by-side in masses of 20 or 30 eggs on the underside of the host plant’s leaves.

If you see egg masses, scrape them off and throw them in soapy water, or just remove the leaf and dip it in the water solution.

Nymphs emerge from eggs after about four or five days. They go through five developmental stages known as instars, the passing from one instar to the next marked by the shedding of a constrictive layer of outer skin, a process called molting. Each instar lasts about a week. Within two weeks of their final molt, another group of adults is ready to begin reproducing.

Your arsenal against stink bugs can include everything from commercially available traps to capture adult stink bugs to using landscaping to deter stink bugs, according to the Farmers’ Almanac.

Marigolds and sunflowers, for example, attract insects that feed on stink bug eggs and larvae. Stinkbugs don’t like mint, so consider planting some around the crops you want to protect or sprinkling crushed mint around the base of plants.

To bolster your protection, consider food-grade diatomaceous earth, a natural compound made from the fossilized remains of tiny, aquatic organisms called diatoms. Sprinkle it on the leaves and the soil under watermelon, cantaloupe, squash, or other fruits and vegetables that rest on the ground.

Or, mix a solution of water and dishwash detergent and spray it directly on the bugs.