Brown Marmorated Stink Bug is the Beast of the East
August 31, 2011 
What We’ve Learned
So far, the brown marmorated stink bug has been officially reported in 33 states and the District of Columbia. In most cases, first reports come from homeowners rather than growers, so there is the chance that later in the season more states could end up on this list.
The good news is, growers were not caught off guard this year. “There was great awareness within the grower community this year regarding the threat posed by this invasive species,” says Tracy Leskey, an entomologist at the USDA-Agricultural Research Service (ARS) Appalachian Fruit Research Station in Kearneysville. “Growers were vigilant in terms of scouting and management specifically targeting BMSB.”
Greg Krawczyk, an entomologist at Penn State University, says their peach crop looks to be in decent shape this year, “but at a cost of multiple insecticide applications.” Since the season is still in progress, “we are faced with a huge challenge in how to prevent adult stink bugs from their potential feast on maturing fruit while still following all PHI and REI requirements for available insecticides.”
As a result of Leskey’s efforts, in tandem with a stink bug working group made up of researchers across the country, we now know much more about BMSB than we did a year ago. “We have found that peaches are extremely vulnerable to damage early in the season as overwintered bugs emerge,” says Leskey. “We also confirmed that BMSB will feed on apples season-long, but that economic injury (indented, discolored depressions with corky flesh) results from feeding that occurs from mid-June onward. Feeding prior to this results in nominal injury.” For more detailed information on when BMSB presents the biggest threat to peaches and apples, click here.
2011 Status And Management
“Most growers have reduced their damage tremendously with aggressive management programs,” says Leskey. “They are using materials that have shown good efficacy in laboratory trials, shortening intervals between treatments, and treating more frequently.”
Penn State researchers Krawczyk and Larry Hull have done extensive research on management options. Much of their efforts were outlined in a special “Stink Bug” issue in the May 2011 issue of Penn State Extension’s “Fruit Times” newsletter, which you can find by clicking here. Specifically, they have looked at BMSB biology and behavior, as well as the efficacy of several insect control products available on the market. Laboratory bioassays conducted in the past year to evaluate these insecticides against BMSB have demonstrated the availability of multiple active ingredients that are effective. Unfortunately, many of them provided minimal direct mortality of BMSB adults.
There is at least some good news coming from EPA. The agency has approved, for emergency use, the insecticide dinotefuran (Venom, Valent U.S.A., and Scorpion, Gowan Co.) on tree fruit. The emergency exemption applies to Virginia, Maryland, Delaware, Pennsylvania, West Virginia, North Carolina, and New Jersey. Under the exemption, producers of stone fruit and pome fruit are allowed to manage BMSB with two applications of dinotefuran by ground equipment per season.
In addition, EPA has also approved a new use for an insecticide that may help manage stink bugs in organic production systems. The new product contains azadirachtin and pyrethrins, which are derived from botanical ingredients.
In August, Leskey provided an update on current field season observations in Maryland and West Virginia.
– Offspring (referred to as summer generation) of overwintered adults have reached adulthood and are mating and reproducing a second generation. Summer and second generation nymphs are now present in the field resulting in substantial overlap in generations now present.
– BMSB feeding on apple is now resulting in economic injury. “We have confirmed that apples must reach a certain stage of maturity for this type of injury to manifest,” she says. Prior
to this stage of maturity, injury resulted in a simple discolored dot with feeding sheath beneath.
– Among monitored apple blocks in Maryland and West Virginia, an average of 13% corking injury is being detected in peripheral areas of blocks.
– Growers who have maintained an aggressive spray program with broad spectrum materials have substantially reduced damage, but increased costs associated with this approach will result in substantial economic challenges.
– BMSB are still being observed in larger numbers on tree of heaven, white ash, silver maple, Paulownia, and other woody hosts. Significant numbers have been detected in corn and soybeans throughout the region.
– BMSB adults are beginning to respond to traps baited with methyl-deca- trieonate.
Challenges And Strategies
While growers and researchers know a lot more about BMSB today than they did a year ago, there is still much that has to be learned. “The biggest challenge will face growers whose orchards are located next to woods or other agronomic crops where BMSB are not controlled adequately such as corn or soybean,” says Krawczyk. “Insecticides may control nymphs quite effectively, but cannot prevent adults from moving from those outside breeding grounds and feeding on maturing fruit. And every single probing or feeding equals new injury on fruit.”
The most pressing step in the fight against BMSB, says Leskey, is in mitigating the overall threat via chemical control. However, the long-term goal is to develop IPM-based strategies for management. “We are working on developing monitoring traps that will detect BMSB presence, abundance, and seasonal activity into orchards and other crops,” Leskey says. “This is based on identifying optimal visual and olfactory cues that can be incorporated into the trap as well as effective capture mechanisms compatible with their behavior and optimal deployment strategy.”
This is just one part of an ARS action plan, funded by federal grants, to combat the stink bug. The plan includes a broad list of short, medium, and long-term objectives. The current plan focuses on determining critical aspects of basic biology, host range phenology, and behavior (including isolation of pheromones); developing monitoring tools; and developing mitigation strategies such as the use of pesticides in the short term, and biological control and trap-and-kill strategies in the long term. For a detailed look at these strategies, click here.
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