Thursday, June 30, 2011

High Cost of Cheap Seed

What do you look for when you buy grass seed for your lawn? A good price? An attractive label? If you’re savvy, maybe you look for the best variety for the amount of shade in your yard. Very few people look at the fine print on the back of the bag for the really important information on weed seed content. They should.

There is a bag of grass seed that has become a permanent fixture in our office. It was bought a couple of years ago as a prize for a Wellness Committee fitness contest. The sorry thing was never given out because somebody read the label and noticed it contained: 87.7% annual ryegrass, 9% perennial ryegrass, 1.5% other crop seed, 1.5% inert matter, and 0.3% noxious weed seed. It then lists the weeds you’d be innoculating into your lawn if you planted the contents of the bag. In this case, annual bluegrass, hairy chess, and curly dock. We work too hard battling noxious weeds in this Department – there was no way we were going to encourage someone to sow more!

Weed seeds have been hitchhiking with desirable seeds for centuries. Something like a third of Oregon’s noxious weeds are thought to have arrived as seed contaminants. It all starts with weeds in the seed fields. The seeds of the weeds get harvested right along with the seeds of the crop. Yellow starthistle, spotted knapweed, dodder, and whitetop have been spread around as seed contaminants. In this day and age, seed cleaning removes a lot of weed seed, but not all of it. Last year in our laboratory, 190 seed lots out of 6,529 (3%) tested failed because of weed seed contamination above allowable thresholds. This week, our lab has processed 43 seed lots. Weed seeds were found in six of them, though infestation levels were below thresholds, so off they went into commerce – weed seeds and all.

Buyer beware. If you buy cheap seed, you’re likely to get the weedy stuff. We should all make a habit of buying good quality, clean seed. Read the label, including the fine print. If you buy cheap weedy seed or untested seed, you’ll probably pay for it later. The US Forest Service (USFS) learned this lesson the hard way.

In 1988, the Tepee Butte fire burned 66,000 acres in Hells Canyon National Recreation Area. Following the fire, the USFS reseeded the burned area by air, including some adjacent private land. The following spring, they discovered the seed had been contaminated with yellow starthistle. Not only did the Forest Service have to spend a considerable amount of money cleaning up their own land, but the private landowner sued and won a six figure settlement. Ouch!

Oregon’s seed law related to weed contamination needs work. The weed seed tolerances (OAR 603-056-0205) were adopted in 1983 and last revised in 1996. Three years later, Oregon’s noxious weed list was adopted as a regulation (OAR 603-052-1200) preventing importation and selling of noxious weeds. This second regulation has been updated almost every year as new weeds are added. The weed seed and noxious weed regulations have never matched and continue to diverge. It makes no sense.

We’ve got work to do. In the meantime, you can help by reading the fine print on seed packages and not sowing more weeds. We’ve got enough already, thank you!

Dan Hilburn

Wednesday, June 22, 2011

Official Survey versus Outreach and Education

Asian longhorned beetle exit holes are about the size of the
diameter of a pencil.
There are two ways that invasive species are detected—people notice and report them, or technicians discover them during surveys. Historically, in Oregon, most of the important early detection discoveries have been the result of surveys. Every single gypsy moth and Japanese beetle infestation ever found in Oregon has been detected by survey before anyone in the public ever noticed the pests or their damage. Sudden oak death in Brookings was first detected during an aerial survey. All the non-native Spartina (saltmarsh cordgrass) infestations on the Oregon coast have been found during surveys. Since the beginning of 2007, 32 new non-native insects/snail species have been found in Oregon—26 (81%) were found during surveys.

There are exceptions. For example, the invasive tunicate in Winchester Bay was reported by an alert volunteer diver working for the Oregon Aquarium. German yellowjackets in Tillamook were discovered by a resident. And Patterson’s Curse in Linn County was recognized by a visitor from Down Under.

Earlier this month, a resident in Bethel, Ohio reported to a state forester unusual damage on maple trees. It turns out the damage was caused by the Asian Longhorned Beetle (ALB), one of the worst invasive species threats to hardwood trees in North America. This is the latest in a string of ALB infestations discovered by citizens in the United States. Unfortunately, the infestations exist for 5–10 years before anyone notices a problem.

There are two good reasons why ALB gets reported by the public:
1)      it is big and weird-looking;  and
2)      there are no good survey methods.

We have some big native longhorned beetles that resemble ALB, but they are not likely to show up in your yard. ALB, on the other hand, feeds on and eventually kills maple, willow, horsechestnut, elm, and other common yard and street trees. Reliable surveys for ALB require tree climbers. From the ground, the best that can be done is to scan the trunks of susceptible trees looking for half-inch diameter exit holes. In the past, Oregon survey crews did this, but looking for a needle in a haystack would likely be more productive.

Clearly, we need more trained people looking for ALB. We think a better strategy is to train master gardeners, arborists, and other people that are on the front lines to keep their eyes open. The same could be said for dozens of other invasive species on Oregon’s 100 Most Dangerous Invaders List Each year there are surveys for only a small fraction of these species.

What can we do? The reality is we need both a robust survey program and an educated citizenry.

Targeted surveys are often critical to successful early detection and rapid response (EDRR) programs. They can be very efficient, especially if effective traps are available. Gypsy moth traps, for example, can attract moths from a quarter of a mile away! Efficient traps are a big reason why we’ve been able to keep the gypsy moth from establishing itself in Oregon, despite repeated introductions during the last 30 years.

When an invasive species isn’t detected early, eradication is often impossible or hugely expensive. The folks that live near Bethel, Ohio are about to find that out. If this ALB infestation is as big and well entrenched as the others that were finally noticed by citizens, millions of dollars will be spent on eradication, and thousands of trees will be destroyed. Check out the video called Lurking in the Trees for a scary look at what happened when ALB was found in Massachusetts (the Oregon Department of Agriculture has copies available for lending).

Recognizing that government can only do so much and budgets aren’t keeping up with the introduction of new invasives, we’ve got to get smarter about our defenses. I don’t think private industry is the only answer—there is no profit to be made from invasive species EDRR, and even well-trained arborists can’t cover Oregon’s geography. What we need is lots of people sufficiently well informed to recognize new weeds and potential pests. Then we need them to report their findings so that the species can be identified and the appropriate responses taken. Digital pictures, many taken with cell phones, are becoming an important tool for transmitting pictures of suspicious weeds, bugs, and snails. Even if the quality isn’t the best, an expert is usually able to determine if further followup is warranted. In Oregon, we’ve made it easy for people to report new sightings with our telephone and online hotlines: 1-866-INVADER or

If we work together, maybe we can avoid what just happened in Bethel, Ohio. ALB would be very destructive to Oregon; we don’t want it here. Because there is neither an  effective trap nor survey, it is up to all of us to remain vigilant. Keep your eyes open, and report it if you see any big weird beetles, pinky finger-sized exit holes in tree trunks, or anything else that doesn’t look like it would be good for Oregon. Collective vigilance is our only hope.

Dan Hilburn

Wednesday, June 15, 2011

Calculating Our Chances of Getting Zebra Mussels

What are the odds Oregon will become infested with zebra or quagga mussels? These invasive freshwater mussels spread quickly in the East after being introduced to the Great Lakes in the 1980s. In 2007, they appeared in Western waters, and since then, they have spread to several western states. To date, Oregon has been lucky; as of today, we don’t know of any bodies of water in Oregon that are infested. We also know that mussels are excellent hitchhikers on trailored boats. What are the odds we can keep Oregon zebra/quagga mussel free? Are we doomed, or can we keep them out? It would be nice to know. Maybe we can calculate the odds.

Since I read my first science fiction book as a boy, I have been fascinated with the idea that there might be life elsewhere in the universe. Frank Drake is famous for his 1961 equation to calculate the number of other civilizations in our galaxy. The equation looks like this:
                                    N = N *  fp * ne * fl * fi  * fc * fL  
N = number of stars in our  galaxy
fp = fraction of stars that have planets
ne = number of planets per star capable of sustaining life
fl = fraction of planets in ne where life evolves
fi = fraction of fl where intelligent life evolves
fc = fraction of fi that communicate
fL = fraction of planet’s life during which communicating civilizations live

Because there are no data for any of these factors except the first one, it isn’t a reliable estimate, but it sure stimulates the imagination! There is even a calculator on the Internet that allows you to input values that make sense to you and see what the odds are that we have galactic neighbors:

We can use a similar approach to estimate our chances of getting zebra/quagga mussels. Here is my amaterish attempt:
                                    P = (N * fo * fz * fd * fin * fa * fe) * 100
                        P = probability the zebra or quagga mussels will become established in Oregon in any                           particular year
                        N = number of boats launches in the state/year
                        fo = fraction of launched boats coming from out-of-state
                        fz = fraction of out-of-state boats infested with zebra/quagga mussels
                        fd = fraction of infested boats not cleaned by owners
                        fin = fraction of infested, non-cleaned boats not intercepted/cleaned at check stations
                        fa = fraction of mussels on dirty boats that are alive at the time of relaunch
                        fe = fraction of mussel introductions that result in established populations

Now comes the fun part. Just like a someone searching for extraterrestrial intelligence, we can take the meager amount of data available, make a series of assumptions, and see what pops out of the equation. Here goes:

N = 375,000 (average of best estimates from Glenn Dolphin, Oregon Marine Board and Rick Boatner, Oregon Department of Fish and Wildlife; there are 46,000 launches during the Lower Willamette River Spring Chinook fishery season alone; 151,691 boats are registered in Oregon)
fo = 1/6 (based on 20% of boats that stopped for inspections in 2010 were from out-of-state, but most of the data came from inspection sites near Oregon’s borders)
fz = 1/5,000 (my guess based on 2,852 boats inspected last year*; none had zebra/quagga mussels, yet we have had two cases of infested boats reported in OR)
fd = ¾ (my guess that only a quarter of boats are cleaned by owners between launches)
fin = 9/10 (my guess that only 1 in 10 infested boats are intercepted and cleaned at inspection stations)
fa = ½ (my guess that half the time mussels on infested boats dry out and die before relaunch)
fe = 1/10 (my guess that 90% of introductions don’t result in reproducing populations)

                        P = (375,000 * .17 * .0002 * .75 * .9 * .5 * .1) * 100
                        P =  43% chance zebra mussels will become established in Oregon this year

Based on this admittedly simple analysis, it shouldn’t surprise anyone if zebra/quagga mussels become established in Oregon sometime in the next few years. Of course, the odds could change. If the fraction of boats coming into the state infested with mussels increases, our odds of avoiding infestation go down. This is likely to happen as water bodies closer and closer to Oregon become infested. On the other hand, if we increase the number of people cleaning their boats between launches, we can improve our odds of staying zebra/quagga mussel-free.

Imagine if 99% of people cleaned their boats between launchings (fd = .01). Keeping all other factors the same, this equation predicts that the probability of establishment would drop to just 0.57% per year. I like those odds better! Let’s all clean our boats between launchings. It’s not that hard. The Marine Board has excellent information on how to do it right at :

Dan Hilburn 

*Dolphin, G. & R. Boatner. 2010. Oregon Aquatic Invasive Species Prevention Program. 2010 Program Report. Oregon State Marine Board, Oregon Department of Fish & Wildlife. Feb. 2011. 22pp.



Sunday, June 5, 2011

The Rise & Fall of Wild Parakeets in Oregon

Did you know there used to be feral parakeets in Oregon? Between 1982 and 2003, there were regular sightings in Oregon, though never very many.* The species was a South American native known as the monk or Quaker parakeet (Myiopsitta monachus). 

We used to worry about monk parakeets becoming an agricultural pest here. In South America, large flocks can damage fruits and grains, and we have plenty of fruit and grain crops in Oregon. Monk parakeet populations were increasing exponentially in the United States until 2003.*
These beautiful birds make huge communal nests. At one time, up to 24 parakeets were living in nests at Portland International Airport (PDX) near the cargo terminal. They were fun to watch and a hit at nearby bird feeders. One of the staff members told me someone had rescued a baby parakeet that had fallen out of the nest; they had taken it home for a pet. The family had a newborn infant, and the parakeet quickly learned to imitate the baby’s cry. It was driving the parents crazy because they couldn’t distinguish the baby’s cry from the bird’s imitation, so they re-released it back into the wild!

The Oregon Department of Agriculture (ODA) debated whether or not to take action. In general, eradicating a new potential pest before it gets permanently established is a good policy. Birds, however, were not our normal business. Over the years, we’ve learned that when in doubt, do a risk assessment. So we did. In fact, a risk assessment of monk parakeets was one of the fist risk assessment ODA ever conducted: The conclusion in 2003 was that the risk was moderate—with a very high level of uncertainty. It was also clear from a review of the literature that people love these birds, and control programs tend to meet fierce resistance from the public. We decided to watch and wait.

It was the right decision. A decade ago, there were two sites with active nests: PDX and Scio. The colonies hung on for several years, then died out or moved out on their own. There hasn’t been a monk parakeet sighted in Oregon on the Audubon Society Christmas bird count since 2006. 

The national picture has also changed. Importation, once unrestricted, is now regulated, and this species is no longer important in the pet trade. Feral populations peaked around 2004 and have been declining ever since. There are still plenty in Florida and other warmer states, though they haven’t become the plague that some people predicted.

An interesting wrinkle in this story is that there used to be a native parakeet in the Southeast. The Carolina parakeet (Conuropsis carolinesis) went extinct in the early part of the last century. No one is quite sure why, but it was heavily hunted for its decorative feathers. It could be that monk parakeets are refilling that empty niche.

Even though the parakeet nests in Oregon have been abandoned, you don’t have to go far to see feral parakeets—there is an active nest now in Yacolt, WA. If you go to check them out and one of them cries like a baby, you’ll know where it came from.

Dan Hilburn

*Butler, C. 2003. Species Status Review: Monk Parakeets in Oregon. Oregon Birds 29(2):97-100.

Photo from