Hazelnuts - Brown Marmorated Stink Bug (BMSB)

Jed Capelazzi
CPS Agronomy
New 2013 BMSB Distribution in Oregon and Washington
Get Prepared and Learn How to ID the BMSB
I wanted to take a minute to offer our growers information on the Brown Marmorated Stink Bug (BMSB) in Oregon as this pest may become more of a problem in the near future.  I will focus on hazelnuts here, but don't think this is the only crop of concern.  In fact there are over 170 BMSB host plants in the US and there are certainly established BMSB populations in Oregons major crop growing regions.  

Brown Marmorated Stink Bug
(by: Christopher Hedstrom)

So, what is the BMSB (Halyomorpha halys)?  Unintentionally introduced to PA in 1996, BMSB has quickly moved across the US.  It is a piercing/sucking insect that uses a proboscis to enter plant tissue, exude digestive enzymes and consume the resulting "juice."  Should it only feed there wouldn't be much of a problem.  However, feeding results in necrotic tissue (typically on fruit or other marketable parts of the plant) and disease.  You can find more information here and here.  Stories on the harm BMSB poses to PNW crops are becoming more common and hazelnuts are of major concern.  Elsewhere in the U.S. the "polar vortex" has done a good job of reducing numbers this year, but the PNW may not be lucky enough to slow the invasion.  We know these pests cause significant damage to apples and other valuable crops (peaches/grapes), but one might reason the hazelnut shell can protect the crop from major attacks seen on succulent fruit.  Unfortunately that is not the case.  

Yesterday at OSU, Christopher Hedstrom defended his masters thesis on "The Effects of Kernel Feeding by Brown Marmorated Stink Bug on Commercial Hazelnuts."  His thesis will be published soon, so check the OSU thesis website if you are interested in the specifics.  As Hedstrom presented, hazelnut developmental stage is a good predictor of damage type.  Below is a graph of feeding damage taken from Hedstrom's research.  As you can see, the three types of damage (blanks, shrivelling and corking) occur at different times.  Blanks occur at a higher rate early in the season (pre-expansion and early shell expansion) when BMSB exudate may either degrade the small kernel or introduce disease that prevents development.  Shrivelling is more consistent throughout development and is likely the result of moisture loss.  Corking is more significant later in the season when the kernel fills the shell.  Corking is reminiscent of damage seen in other fleshy fruits like apples.  Interestingly, Hedstrom also found increased shell thickness did not reduce damage.  Also, shell brown stain and early cluster drop appear unrelated to BMSB.

Research by Christopher Hedstrom

As the 2014 season gets under-way, it is important to think about the BMSB as an emerging issue in Oregon.  Tracking population spread is a great place to start.  The more eyes we have the better! OSU has a website where you can report sightings (remember there are a lot of other confusing stinkbugs out there).  Crop Production Services will be vigilant as well.  Although pheromone traps for BMSB are still in developmental stages, we will be placing and checking a variety of traps throughout the year.  The best way to find BMSB remains the "beat sheet," where you lay a sheet on the ground under a tree (canvas) and literally beat the tree with a broomstick.  If present, BMSB will fall onto the sheet.  

For some peace of mind before I go, research on a parasitoid of BMSB eggs is ongoing and the future may hold a biological control option (story).  

You can find out all the BMSB information you would ever want to know here and here.