Stink Bug: A Grower’s Nightmare

In late October, the U.S. Apple Association and the American Farm Bureau Federation coordinated a briefing from researchers and administrators at USDA and the Agricultural Research Service (ARS) on BMSB, what we’ve learned so far, and what growers can expect in both populations and control strategies in 2011. Much of the briefing focused on tree fruit damage surveys conducted this past year by Tracy Leskey of the USDA-ARS Appalachian Fruit Research Station in Kearneysville, WV. The following are 10 items addressed in this briefing that you should know.

1) BMSB is an invasive species that is native to the Far East and was first identified in a Pennsylvania orchard in 2001. It is believed to have been delivered accidentally via shipping material.

2) Up to six generations of BMSB per year have been recorded
in Asia.

3) According to Leskey, BMSB has a very wide crop host range. While apples and peaches were the most affected in 2010, it also targets grapes, pears, berries, and some vegetables.

4) Unlike native stink bug species, both adults and nymphs have been found to feed on fruit.

5) BMSB wreaks havoc not only on fresh apples; it burrows so deeply into the flesh that in many cases, processors will also reject the fruit. Again, this is a striking difference compared to the native stink bug species.

6) BMSB is considered a “landscape level threat” because it can and will feed anywhere. It enters orchards from the outside, but if populations are left unchecked, reproduction can occur within the orchard, which leads to rapid population build-up.

7) Even the best IPM strategy will be irrelevant in the face of BMSB. This past year, growers in the mid-Atlantic were forced to make late-season pyrethroid applications, which disrupted beneficial activity.

8) Because even small populations can be damaging, a very aggressive treatment program may be required. Compounding this, Leskey says the damage surveys yielded between 60% and 80% survival following applications, with little to no residual activity.

9) Because there are no proven attractants, adult captures in traps during Leskey’s surveys were not reflective of in-orchard activity.

10) If you are an organic grower, Leskey described the impact of BMSB in one word: “devastating.”

Add up each of these considerations, and it’s not hard to understand why apple and peach growers in Pennsylvania and surrounding states reported crop losses of 60% to 80%, in some cases even higher. As ARS team research leader Michael Glenn stated during the briefing, “If these growers have these kinds of losses next year, they will not be in business very long.”

Building An Action Plan

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. These efforts involve support from several ARS research stations, university programs, and federal agencies such as the National Institute of Food and Agriculture and USDA’s Office of Pest Management Policy.

– Short-Term: Define a rational chemically based management strategy as an immediate emergency stop-gap rescue strategy, and as part of a sustainable pest management plan. At the present time, growers are applying pyrethroids and carbamates in an attempt to save their crops. Chemical control is not considered desirable over the long-term, due to disruptions to IPM programs, but will play an immediate role in salvaging crop production. Researchers will also seek to define an appropriate short-term chemical control strategy for the 2011 season, which should include expedited EPA reviews.

– Medium-Term: Define the basic biology, phenology, and behavior of BMSB. In order to develop a management plan, researchers will quantify and verify the basic biology of BMSB throughout the region. It is critical that the basic biology and behavior be well understood in order for researchers to be better positioned to develop effective and appropriate monitoring tools and management strategies.

– Medium-Term: Establish the host range and preference of BMSB for both cultivated and wild hosts as well as susceptibility of cultivated hosts.

– Medium-Term: Assess and survey BMSB populations to establish geographic distribution, population density, and potential spread. BMSB is highly transient and has already been found in 29 states. Scientists’ efforts to monitor this spread will be critical to determining the presence, establishment, abundance, and activity of BMSB in order to inform regional management decisions.

– Medium-Term: Develop an effective stimulus-based monitoring tool for BMSB. Scientists are working to identify aggregation and mating chemicals that can be used to monitor BMSB. These efforts will, ultimately, underpin successful management strategies, detection programs, and biological control efforts.

– Medium-Term: Develop an effective attract-and-kill management strategy for BMSB.

– Long-Term: Establish biological control efforts. BMSB is an invasive species that operates at a landscape level, utilizing numerous wild and cultivated plants, throughout the spring and summer. In addition, adults aggregate in large groups during particular periods of the year. A biological control agent, whether parasitoid, predator, or pathogen, could reduce or eliminate this insect as a pest of agricultural and urban settings. The identification and development of such an agent is the ultimate, long-term goal of research efforts.

As Leskey notes, one thing is certain: A large population of BMSB is going into overwintering right now, so expect to see even higher populations in the spring. It’s imperative to get a handle on when they will emerge, and to be ready when that happens.