Stinkbug Explosion!

Lee Royer
Frederick County Master Gardener

The 2011 Brown Marmorated Stink Bug season officially began on April 7 when the first overwintered adult stepped into an experimental pheromone trap placed by researchers in a commercial orchard near Frederick. Unfortunately it appears the harsh winter followed by a wet spring did not dampen their spirits.

According to Bryan R. Butler, Sr, a regional fruit educator working with the University of Maryland Extension, until the week of May 23 numbers were relatively low. However since May 23rd adults have been swarming into fields in significant numbers. While it may be hard to believe, given the numbers homeowners were plagued with last fall, more have been observed entering fields and orchards from surrounding natural locations such as wooded areas rather than manmade structures.

Buyers beware. Traps used to lure BMSBs for monitoring are still in the experimental stages because specific BMSB pheromones are in the process of being isolated and studied. The public should be aware traps offered for sale at this time have not been subjected to rigorous independent scientific tests.

Be cautious also of products claiming to control BMSB. Many products are being tested but the magic bullet does not exist for either organic or non organic growers this year. These facts will not stop the avalanche of advertizing, email offers, and viral videos produced by those selling or in some cases, giving away, all sorts of dubious stink bug products and information. Use reputable scientific resources listed below for research.

Butler reports damage has been noted in strawberries, raspberries and cherries. Already damage to peaches in some sections of scientifically observed orchards has been as high as 25% and in some sections of apples as high as 15%. It is not known how this compares to last year because it was not until later in 2010 that Dr. Tracy Leskey of the Appalachian Fruit Research Station in Kearneysville made the discovery that BMSBs were responsible for losses observed in a wide variety of crops, trees, and landscape plantings.

The scary part is yet to come, as these adults are now laying eggs that in two weeks time will quickly hatch into nymphs which will immediately begin feeding on the same plants and soon enough repeat the process of laying eggs.

So what can you do? Now is the time to study the photos you see with this article so you can destroy the eggs and nymphs which are more easily killed than the extremely hardy and more mobile adults. Smash the egg masses and spray insecticidal soaps (homemade or commercial) on the nymphs.

The female BMSB most often lays eggs in triangular groups of 20-30. Easily seen by the naked eye, the eggs are spherical-shaped, not perfectly round, pale green to white and may be found on the underside of leaves, pretty much any kind of leaf. Females lay eggs about once a week and may be able to lay over 250 before seeking out shelter for the winter hibernation.

Scientists have not been slacking when it comes to BMSB research. The BMSB Integrated Pest Management Working Group lead by Tracy Leskey, Research Entomologist at the US Department of Agriculture, WV and George Hamilton, Extension Specialist in Pest Management, Department of Entomology Chair at Rutgers University, New Brunswick, NJ began monitoring BMSB many weeks before the April 7 first sighting. For more information on the members and goals of the working group, see

The University of Maryland is at the forefront of BMSB research. Find answers to questions about BMSB and reputable links to more information at Invasive Species tab.

UM Extension Frederick County Master Gardeners will be planning seminars on BMSB for late summer or early fall. To be notified of details on upcoming BMSB seminars or answer local questions, contact us at

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