Brown marmorated stink bug: Halyomorpha halys

The brown marmorated stink bug, Halyomorpha halys, is a voracious eater that damages fruit, vegetable, and ornamental crops in North America. The insect uses more than 170 plants for food and reproduction, and threatens an estimated $21 billion worth of crops in the United States alone.

Since the brown marmorated stink bug (BMSB) first appeared in Allentown, Pa., in 2001, it has become a serious pest throughout the Mid-Atlantic region. The stink bug continues to spread to other regions within the U.S. wreaking havoc on various crops and causing a nuisance to people in residential areas. Currently, it has been found in 42 states and two Canadian provinces.

The BMSB is native to China, Japan, Korea, and Taiwan. Although no one knows for sure when and how the BMSB ended up in the United States, some speculate that it came in through an imported commodity such as an auto parts container, manufacturing equipment, textiles, office supplies, or agricultural products in the early 1990s. All of these products arrive in the U.S. from Asia in boxes, crates, or shipping containers, making an easy hiding place for a stink bug to catch a ride.

Adults will aggregate or overwinter in homes and other structures, and can become numerous in attics and porches. They find abundant host plants in neighborhoods on which to feed and lay eggs. Because this invader thrives in urban and natural habitats, it could prove difficult to manage in specialty crops.
 

The Guide

Follow these tips to prevent brown marmorated stink bug from damaging plants at your nursery.
 

Natural enemies. The Asian wasp Trissolcus japonicus has been found in the wild in the United States. The wasp, native to the regions of Asia where the brown marmorated stink bug (BMSB) originates, is known to attack the eggs of BMSB and possibly other stink bugs.
 

Tips from the source. A collection of articles originally published in China, Japan, and Korea and translated with American Farm Bill funds yielded tactics used in Asia against BMSB.

BMSB is often difficult to detect because it hides in gaps between leaves and fruit in trees. Therefore, branches and the trunk need to be shaken just forcefully enough so that fruit does not fall from the tree to check for the presence of pests.

Other tactics include light traps for monitoring and management, removing egg masses, capturing stink bugs physically, using a buffer zone plant around cash crops, and creating an encouraging environment for parasitic wasps such as the Trissolcus species. Some researchers wrote that the stick-beating method causes bugs to drop, then pesticides can be applied on the ground under the tree.

Luring them in. An attract-and-kill strategy for BMSB would involve luring large numbers of the insects to a specific area, and then treating that area. Such a program could reduce pesticide applications, save money and minimize health and environmental risks. But mass trapping of BMSB has not yet been shown to be an effective or economical control.

Some researchers are exploring BMSB lures as the basis of an effective monitoring strategy.

For more tips on stopping BMSB, visit www.stopbmsb.org.

The facts about Halyomorpha halys

Locations

Brown marmorated stink bug (BMSB) has been found in 42 states and two Canadian provinces. It has caused the most crop damage in the Mid-Atlantic region.
 

Host Plants

BMSB isn’t a picky eater. Agricultural commodity groups are working with researchers to document BMSB populations in orchard crops, small fruit, grapes, vegetables, and ornamental plants throughout each growing season. BMSB specialists are also studying the pest’s presence in wooded areas and structures to get a sense of where it spends its winters.
 

Damage

In its native range, it feeds on a wide variety of host plants. Fruits attacked include apples, peaches, figs, mulberries, citrus fruits and persimmons. This true bug has also been reported on many ornamental plants, weeds, soybeans and beans for human consumption. Feeding on tree fruits such as apple results in a characteristic distortion referred to as “cat facing,” that renders the fruit unmarketable as a fresh product.
 

Appearance

Adults are approximately 17 mm long and are shades of brown on both the upper and lower body surfaces. They are the typical “shield” shape of other stink bugs, almost as wide as they are long. To distinguish them from other stink bugs, look for lighter bands on the antennae and darker bands on the membranous, overlapping part at the rear of the front pair of wings. They have patches of coppery or bluish-metallic colored puntures (small rounded depressions) on the head and pronotum. The name “stink bug” refers to the scent glands located on the dorsal surface of the abdomen and the underside of the thorax.
 

Life cycle

BMSB overwinters as adults in a protective sleeplike state, emerges in the spring, and begins mating in about two weeks. BMSB commonly mates multiple times, and the female may deposit as many as 486 eggs in a lifetime.

Development from egg to adult requires approximately 538 degree days, a measure of temperature and time for insect growth, with an additional 148 degree day period before eggs are laid. Its light-green eggs are often laid on the underside of leaves, deposited in masses of approximately 28 eggs.

While the adults blend in with tree bark, the nymphs are more brightly colored. BMSB has five nymphal stages ranging from 2.4 mm to 12 mm in length. Early-stage nymphs do not venture very far from the newly hatched egg mass. The legs and antenna of nymphs are black with white banding. Early-stage nymphs have dark reddish eyes and a yellow-reddish underbelly with black stripes.
 

Chemical Control

Chemical control is not considered desirable over the long-term, due to expected crop resistance to these chemicals and disruptions to integrated pest management programs, but will play an immediate role in salvaging crop production and a limited, ongoing role in more sustainable management programs.
 

Biological control

Researchers have identified a group of tiny parasitic wasps, Trissolcus, that is known to attack BMSB eggs. In addition, a naturally occurring fungus, Ophiocordyceps nutans, attacks BMSB in Japan, and other fungi have been shown to target BMSB in laboratory studies. Ultimately, a program of natural biological control could provide the safest, most effective, and economical approach to tackling BMSB.

Sources: Penn State University Department of Entomology, USDA APHIS, www.stopBMSB.org