A Second Look at Giant Reed and Brown Marmorated Stink Bug

When a new pest or weed shows up in Oregon, some agency has to decide whether to fight back or not. Sometimes we pull out all the stops and attempt eradication/containment (gypsy moth, kudzu, Japanese beetle); sometimes it is not worth worrying about or not a good use of scarce funds (European paper wasp, rusty crayfish, pavement ant). In recent years, we’ve used pest risk assessments to help better inform the decision makers. 

Recently, two species that the Oregon Department of Agriculture (ODA) put in the “not worth worrying about” category have come back to our attention, and we’re giving them a second look. They are giant reed (Arundo donax) and brown marmorated stink bug (Halyomorpha halys).

Giant reed is a noxious weed in tropical and warm temperate areas around the globe. It is a real problem in California, especially along rivers. You can buy it here in Oregon as an ornamental, and we’ve never seen it become feral. My wife planted a variegated variety in a corner of my yard a few years ago. It never flowered and didn’t act invasive. Test plots in Prosser, Washington have produced impressive yields and no evidence of invasiveness.  Apparently the fuel made from giant reed has more British Thermal Units (BTUs) than coal.

ODA did a pest risk assessment on giant reed in 2007. The conclusion was that giant reed should be placed on our Watch List, but didn’t warrant listing as a noxious weed. We’re north of its expected potential range. As a result of that report, giant reed was removed from Oregon’s official state noxious weed list and the Oregon Invasive Species Council’s list of 100 Most Dangerous Invaders.

So what’s the problem? Maybe there isn’t one, but PGE is looking into planting many of thousands of acres of giant reed around Boardman to provide an alternate fuel for their coal-fired power plant. It is an intriguing idea, but such large plantings were never contemplated during the risk assessment process. Converting a coal plant to a sustainable, locally grown fuel would be a good thing – unless it escapes, adapts, and becomes a noxious weed ala California. It is time for us to take another look. 

Ditto for brown marmorated stink bug. This Asian pest was discovered first in Pennsylvania (1996) and has now spread to at least 15 other states. It showed up in southeast Portland in 2004 and has been spreading in Oregon ever since. This fall, for the first time, it is not hard to find in Salem.  Specimens have also been found in Sandy, Aurora, and McMinnville. When it first arrived in the United States, officials decided not to try to eradicate brown marmorated stink bug. The three major reasons for this decision were: no detection trap existed, stink bugs are difficult to kill even with chemical pesticides, and the public backlash to wide-area pesticide spraying in residential areas would have been considerable. We may regret that decision.

Up until now the biggest complaint we’d heard about brown marmorated stink bug anywhere in the country was that it liked to overwinter in houses. Quite suddenly this fall, farmers in the mid-Atlantic states have noticed high numbers and considerable crop damage to a wide variety of fruits and vegetables. Homeowners are also complaining about extremely high numbers crawling on and into their houses. This is not a good sign for Oregon. In a year or two or three, we could be in the same boat.

We’re already wondering if our counterparts in Pennsylvania made the right decision not to fight back when brown marorated stink bug was first discovered and in turn if we made the right decision here in Oregon. Stay tuned for more on these two newcomers.

Dan Hilburn