Jim Birkholz, owner of Pleasant Valley Orchard, begins our Spring Series with a class on pruning fruit trees and another on insects and diseases of fruit trees.  Jim brought me back information when he was at the Fruit Growers Conference concerning a new threat to fruits and vegetables.

The brown Marmorated stink bug  (BMSB) is another gift from Japan, Korea, and China.  The word marmorated refers to its marble-like color.  It is also called the yellow-brown or East Asian stink bug.  It was first found in the U.S. in 2001, in Pennsylvania and is moving west.  Established populations have been found in Oregon and California but that could be from hitchhiking on produce.

The marmorated stink bug has the typical shield shape of our area stink bug.  The upper side of the body has mottled shades of brown and grey and is covered with dense puncture marks.  The underside of the body is white, sometimes with grey or black markings.  They have dark red eyes and the legs are brown with white bandings.  To see a picture of the marmorated stink bug you can visit this website: http://www.insectidentification.org/true-bugs.asp

It has a large number of hosts and they are highly mobile so they can move from early ripening fruit to those that ripen later so almost any crop that has fruit is at risk.  Like other true bugs, the brown marmorated stink bug feeds by sucking on plant juices with it’s beak, which is made of straw-like mouth parts.  The damage can range from mild to severe.

In apples the damage is commonly confused with a disorder called cork spot, leaving damage beneath the skin.  If damage is early in the season the result is cat-facing and brown lines on the fruit surface.  Late season damage can leave water soaked spots beneath the skin.   It also attacks pears, cherries, raspberries, grapes and currants.

On beans, damage is found on the immature seeds within the pods.  This stink bug also attacks green beans, asparagus, and peppers.  There are several  ornamental trees and ornamental shrubs that are also hosts for this stink bug.  I’m sure that as we learn more about this insect the number of hosts will grow.

The BMSB has not become a problem in our area… yet.  Management planning is still under development for this newly introduced pest.  Hopefully by the time it becomes a real problem, we will be able to control it.  In the meantime, early detection of all exotic pests is critical.  With luck and early intervention, we may be have better luck fighting off this stink bug than we have had with earlier beetles and bugs.


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