[Fall Invaders] 'Reek'-ing Havoc

Nothing puts a cramp on enjoying lazy summer days like the smell of pungent insects infesting homes and buildings en masse. If you followed the headlines of last summer, then you likely will remember the boom in stink bug populations the eastern U.S. experienced and the aggravation of homeowners that soon followed. This pest’s rapid emergence has many PMPs asking where these insects came from and how they are best controlled.

Brown marmorated stink bugs (Halyomorpha halys) are the latest pest to gain national notoriety. Adult brown marmorated stink bugs (BMSBs) are easily distinguished from other native brown stink bugs by their larger size, light colored banding on the antennae and legs and alternating light and dark bands on the rim of the abdomen. Originally identified in the late 1990s in Allentown, Pa., the BMSB is an invasive agricultural and overwintering pest that may have entered the United States as hitchhikers on shipping containers from East Asia. With a penchant for slipping into unexpected places, it is no surprise that stink bugs are established or have been spotted in more than 30 states.

An Unchallenged Pest. Brown marmorated stink bugs have no natural predators in the U.S. and are known to feed on more than 300 seed-and-fruit bearing host plants. Like many plant-feeding insects, the BMSB has piercing, sucking mouthparts that enable them to penetrate the surface of fruits and seeds to siphon the juices and nutrients as their primary food source. Damaged fruits and crops appear brown and spongy on the inside and lack flavor in the areas that were pierced. Crops that exhibit physical damage are unmarketable according to the USDA crop grade standards.

Adults and nymphs actively feed on fruits and seeds beginning in late July and into early September. Direct feeding on fruits or seeds will not harm the plant itself, nor will the fruit be inedible. However, the damage adds up when thousands of these pests are attacking hundreds of acres of orchards, as has been the case in the mid-Atlantic region since 2008. Within four years, severe damage to apples, peaches and several other stone fruits was observed in all mid-Atlantic states, causing some growers to lose up to 90 percent of their annual crop. In 2010, the BMSB accounted for $37 million in damages to apple growers in the mid-Atlantic region alone.

Urban Invasion. The BMSB emits an unpleasant odor when threatened or in aggregation. Homeowners battling this pest often describe the experience as maddening and even compare the struggle to that of slaying the Hydra — catch one and flush it down the toilet, two more shall appear.

BMSBs will begin infiltrating residential homes and commercial buildings in late August when decreasing temperatures and day lengths triggers diapause — near dormancy — for the summer adults. Adults congregate in large numbers on host plants and begin entering structures to overwinter. While most homeowners do not realize their home is harboring overwintering insects, the BMSB sets itself apart as a true nuisance pest because the adults become active and begin appearing in the living areas of a home when winter temperatures temporarily increase. The activity tends to decrease as winter temperatures decline.

The length of time that BMSBs overwinter inside of a structure is longer than the period spent by other overwintering insects; BMSBs enter structures in late August and leave around May. Most other overwintering insects typically enter structures in late October and vacate by March.

Challenges. Controlling the BMSB has proven difficult in agricultural settings, as well as for residential and commercial clients, due to a lack of effective pesticides. The BMSB’s tenacity in entering structures and labor intensive treatment process create additional challenges in urban environments. The boom in BMSB populations throughout the country further exacerbates the pest management industry’s need for effective control methods.

There are several classes of insecticides, mostly pyrethroids and neonicotinoids, which provide effective control of adult stink bugs as a topical spray. Unfortunately, most pesticide products containing these active ingredients provide little or no residual effect. These materials are registered for use outdoors, on and near various plants and may be labeled for direct exterior application on structures. There are virtually no products available to control BMSB indoors. However, LG LifeSciences’ LambdaStar 9.7% CS gained a label amendment in New York State, adding the BMSB to the list of target pests and provides label guidelines for indoor and outdoor treatments. Other companies are also seeking federal and state label amendments for their materials.

One tactic that has seen success in reducing overwintering activity is treating host plants that harbor large numbers of BMSBs prior to entering the structure. A combination of strategic exterior treatments targeting edge lines and inflection points, interior spot treatments and proactive treatment of potential host plants will provide the best chance for a successful treatment against overwintering BMSBs.

In light of extreme crop losses in recent years, the EPA approved emergency use of dinotefuran (a neonicotinoid), sold as Venom and Scorpion (Valent), for stone fruit, apple and pear growers in the mid-Atlantic region. Though proven effective in Japan since 2002, experts believe suppressing BMSB populations in agricultural fields will have little effect in terms of reducing the overall population due to its appetite for a variety of plants.

Brown marmorated stink bugs are adept in gaining entry into homes and buildings. Physical exclusion of pests is always the best option. Most homeowners will turn to pest management professionals for cost-effective help. Timing is most critical in the delivery of a preventative treatment. Since the BMSB begins entering homes late August through mid-September, preventative treatments rendered during the end of summer have proven most effective for residential and commercial clients. The success of a preventative overwintering treatment further depends on the technician’s thoroughness in treating around all edge lines, window and door frames, rooflines, flashing, ridge vents and inflection points on a structure. The nature of overwintering treatments also requires ladder work, usually 28 feet or higher. The intensive labor of BMSB jobs coupled with the heat and humidity of summer can make preventative overwintering treatments for BMSBs result in a stressful month for PMPs.

However, with meticulous planning and arduous labor come great rewards. Like many mid-Atlantic firms, Cooper Pest Solutions, in Lawrenceville, N.J., began fielding BMSB calls from clients in 2007 and provided overwintering treatments with modifications. Rutgers University and Cooper Pest Solutions have researched and developed a methodical approach to overwintering treatments for BMSB with great success. Cooper Pest Solutions studied its BMSB callbacks and found over the two-year period from 2010-11, the firm achieved about 90 percent customer satisfaction. Additionally, Cooper Pest Solutions reported it had two years of $120,000+ revenue generated as a result of its stink bug service. These success rates show it is possible to seize new business opportunities even during a tough economy rather than dreading the upcoming BMSB season.

George Hamilton is entomology chair at Rutgers University. Lynette Yang is an entomologist formerly with Cooper Pest Solutions. Rick Cooper is a graduate student at Rutgers.

For information on brown marmorated stink bugs’ lifecycle, visit www.pctonline.com and click on “online extras.”