Report on brown marmorated stink bug task force meeting in Pennsylvania

MSU’s tree fruit experts are learning from East Coast experience about the brown marmorated stink bug. None have been found yet in Michigan in 2011.

They gathered seven miles north of the Gettysburg battlefield memorialized in President Lincoln’s famous speech. The first one to speak appeared exhausted, with an underlying tone of defeat in his voice as he pleaded with the group, “We need help.” Two others were to follow, each as weary and desperate-sounding as the first. Civil War soldiers come to swap battle stories? No, three growers invited to talk to the brown marmorated stink bug (BMSB) working group assembled in Biglerville, Pennsylvania, at the Pennsylvania State University Fruit Research and Extension Center, June 20-21.

These three men recounted their current efforts to protect apples and peaches from the new stink bug pest. They had literally come directly from spraying to address the group, each expressing uncertainty about their ability to continue their spray programs due to cost, outbreaks of secondary pests and lack of sustainability.

The BMSB working group is comprised of university personnel, government agencies (state and federal), farmers and chemical company representatives. The attendees gave research updates on a variety of topics. Below is a list of topics that were covered.

Biocontrol efforts. Several parasites from Asia (native land of the BMSB) show promise and are being considered for release in the United States within three to five years after host specificity testing is complete.

Trapping. For both field monitoring and for in-home removal of overwintering infestations, updates on trap design and pheromone attractant.

Cultural control. Varietal differences and border applications are being explored.

Insecticides. Efficacy in the lab and field, new materials and new registrations are being tested.

Phenological studies.Preliminary results on the effects of adult and nymphal feeding at different times during the season are being researched.

Regulatory issues. New pesticide registration procedure and progress: specifically a Section 18 for dinotefuran.

By the end of the two-day session, it was apparent that much research is being conducted and there is reason to be hopeful that it will result in effective management tactics. However, we still have a lot to learn about this important new pest. Mid-Atlantic growers have the disadvantage of being behind the 8-ball right now with most areas experiencing high levels of pest pressure due to two generations of BMSB in 2010. Many growers are modifying their IPM programs to include weekly applications of insecticides starting at petal fall without seeing sufficiently reduced damage (example: 70 percent down to 50 percent). How early season damage manifests itself at harvest is still unknown, but BMSB adults and nymphs are feeding on peaches and apples in early season (prior to pit hardening).

Almost every researcher who spoke reported on lab and field insecticide trials. The primary hurdle for management of BMSB with chemicals is that only the harshest insecticides show efficacy on the adults and repeated applications are needed due to short residual control and highly mobile BMSB adults. A negative side effect of the repeated application of broad-spectrum chemicals is that growers are seeing secondary pest outbreaks of aphids, scales, mites and mealy bugs that were biologically managed under previous, “softer” IPM programs.

Michigan growers should be concerned about this serious threat, but also need to keep in mind that a total of just four BMSB were discovered in 2010 and none have been reported so far in 2011. Increases in stink bug feeding damage, cat facing and apparent bitter pit or cork spot are signs that indicate that BMSB may be active in your area. Michigan State University and MDA researchers and Extension professionals are being proactive in our approach to acquire the best information available and to prepare for the time if and when BMSB becomes a significant agricultural pest here. Also, we have the advantage of using the information being collected on the East Coast populations in terms of biology, ecology and management. We will also likely have only a single generation per year —compared to two in Maryland and Virginia— which should reduce the intensity of early season damage.

Michigan State University personnel are currently monitoring for this pest in many areas in the Lower Peninsula. To date (June 28, 2011), none have been detected in our over 20 traps. With time, we will understand where BMSB is a real threat in the state and when it becomes active. If you find a stink bug that you believe to be BMSB, or are noticing increased amounts of stink bug damage, please collect specimens and send them to MSU Diagnostic Services for identification.  See tips on submitting insects for identification.

The work of Dr. Grieshop and Dr. Gut is funded in part by MSU’s AgBioResearch.

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