Monday, September 30, 2013

Kiss Your Ashes Goodbye?

My heart broke when I heard that the Emerald Ash borer had been detected in Colorado.  The September 23rd siting in Boulder County, Colorado marks the western-most siting of this game-changing pest.

Emerald ash borer, often abbreviated as EAB by those unlucky enough to be familiar with the pest, feeds on any and all species of North American ash (Fraxinus species).  Trees at risk include the beautiful Oregon Ash (Fraxinus latifolia).

Oregon Ash (Fraxinus latifolia) is an important tree in urban and suburban landscapes, as well as an important native tree in riparian areas up and down the Willamette Valley.
The adult beetles nibble on ash foliage but cause little damage. However, the larvae (the immature stage) feed on the inner bark of ash trees, disrupting the tree's ability to transport water and nutrients.   Once infested, the tree canopy begins to thin.  Heavily infested trees show canopy die-back, usually starting at the top of the tree.  In one year, 1/3-1/2 of all tree branches may die, and most of the canopy can die back within 2 years.  Since first detected in Michigan in 2002, EAB has killed an estimated 50 million ash trees.
The canopy of infested trees begins to thin above infested portions of the trunk and major branches because the borer destroys the water and nutrient conducting tissues under the bark. Heavily infested trees exhibit canopy die-back usually starting at the top of the tree. One-third to one-half of the branches may die in one year. Most of the canopy will be dead within 2 years of when symptoms are first observed. Sometimes ash trees push out sprouts from the trunk after the upper portions of the tree dies. Although difficult to see, the adult beetles leave a "D"-shaped exit hole in the bark, roughly 1/8 inch in diameter, when they emerge in June. - See more at:
The canopy of infested trees begins to thin above infested portions of the trunk and major branches because the borer destroys the water and nutrient conducting tissues under the bark. Heavily infested trees exhibit canopy die-back usually starting at the top of the tree. One-third to one-half of the branches may die in one year. Most of the canopy will be dead within 2 years of when symptoms are first observed. Sometimes ash trees push out sprouts from the trunk after the upper portions of the tree dies. Although difficult to see, the adult beetles leave a "D"-shaped exit hole in the bark, roughly 1/8 inch in diameter, when they emerge in June. - See more at:

Prior to the Colorado siting, EAB sitings have been restricted to East of the Rocky Mountains.  

Emerald Ash Borer Distribution Map, December, 2012.  Red dots are sites of initial detection.  White areas on the map are areas of general infestation.  Map source: 
Now that EAB has crossed the great barrier of the Rocky Mountains, it is likely only a matter of time until the beetle reaches Oregon.  EAB adults can fly at least a 1/2 mile from the tree where they emerge.  However, most infestations are likely the result of people moving firewood, people moving nursery trees, or people moving logs from an infested area to an uninfested area.

If EAB makes it to Oregon, large expanses of native ash are at risk.  In fact, I overheard one city arborist talk about how he's stopped using ash as street trees, because 'it's not a matter of if, it's a matter of when emerald ash borer arrives'.  This was 3 years ago.
Areas at risk of Emerald Ash Borer Infestation.  Note the predominance of red and yellow up and down the Willamette Valley in Oregon.  Map source:
If EAB arrives in Oregon, street trees will suffer.

Emerald ash borer damage (David Cappaert, Michigan State University,

But most heartbreaking of all, Oregon Ash in riparian forests may perish.

Image Credit:

What can you do to help stem the spread of EAB?  At this point, when EAB has not yet been confirmed in Oregon, the most important thing you can do is to be aware of this pest ~ so that you can be a first responder to an invasive pest.

  1. Familiarize yourself with the signs and symptoms of EAB.  Good resources are listed, below.
  2. If you suspect that you may have EAB in ash, report your finding to the Oregon Invasive Species hotline.  If you want confirmation on a suspected EAB beetle, you can always take it to your local OSU Extension office.   

Thursday, September 26, 2013

What's in a Name?

Below is a reprint of the article I wrote for the September 2013 issue of The Gardeners Pen (the newsletter of the Oregon Master Gardener Association). 

What is a Master GardenerTM?
By Gail Langellotto
Statewide Coordinator, OSU Extension Master Gardener Program

When someone asks you ‘What is a Master Gardener?’, how do you respond?

Do you say that you’re a volunteer?  Do you say that it’s an Extension Program, or an Oregon State University Program?  Do you say that it’s an educational program?

The way we describe ourselves has a critical impact on how the public views our program.  And, quite honestly, the term ‘Master Gardener’ can be confusing. 

Take, for example, the March 1, 2013 blog post entitled ‘So What Do We Think of “Master Gardeners”?’.

To paraphrase the post, the word ‘Master’ in ‘Master Gardener’ can lead to problems, such as:

  • People thinking it’s similar to “Master Carpenter,” or “Master Electrician”.
  • Some volunteers taking the title a little too seriously, and letting it go to their heads.
  • People assuming that ‘Master Gardeners’ have received a higher level of training than folks with a university degree in horticulture.
Passionate opinions were expressed, from garden writers and other professionals who believe that Master Gardener volunteers are taking work from them, to folks who have had a bad experience with Master Gardener ‘cliques’ and generalize across all.  Of course, where humans gather, there is always going to be the potential for friction. However, I have found (and many of the commenters on the blog post agree) that Master Gardeners are by and large among the most generous, fun-loving, creative and welcoming folks I have met. 

Master Gardeners (and me) enjoying Mini-College, and annual educational event of the OSU Extension Master Gardener Program and the Oregon Master Gardener Association.
What can you say when someone asks you, ‘What is a Master Gardener?’  Luckily, ‘Building public understanding of the Master Gardener Program’ was identified as a high priority in the 2010 OMGA strategic planning process, and developing a common message was one specific recommendation made.  A communications committee, consisting of myself, Sherry S. (Clackamas County), Mary Jane B. (Lincoln County), Bonnie C. (Douglas County), Jan E. (Central Oregon) and advised by Eric B. (Central Gorge), Toni S. (Central Oregon), Lee Ann L. (Multnomah County), Carol O. (Jackson County) and Alan W. (Yamhill County) was tasked with developing this common message.

We came up with three messages, which can be found on page 5 of the OMGA Chapter Toolkit for Communications Toolkit. One of these messages now appears on the Master Gardener website.

“Master Gardeners are trained volunteers, educated through OSU Extension Service to offer the local community Reliable, Relevant and Reachable gardening information and education opportunities."
  • We are reliable, because our gardening advice and education is science-based.
  • We are relevant, because unlike information found online, our advice can be customized for each unique gardening situation.
  • We are reachable, because you can call us on the phone, email us a question, or visit with us at markets or gardens in your community.
We hope that this phrase will be useful, when you’re telling friends, trainees, clients and others about the Master Gardener Program.  And remember, that their interaction with you will really influence what they think about the Program, in general.

Friday, September 20, 2013

Yellowjacket Calls increase in the Fall

The calls have started.

While mowing the grass, someone gets stung several times by a 'bee'.  What can they do to deal with the problem.

Although it is impossible for me to identify the culprit with 100% confidence, unless I can see a sample of the offending insect (or at least, a photo), I suspect that the assailant is not a bee, but is instead, a yellowjacket.

Yellowjackets forage for sugar and carrion.  You'll find them attracted to your soda-pop, as well as your tuna sandwich.

Here's why.
  1. Yellowjackets nest in the ground.  
  2. Of the bees that nest in the ground, most do not sting ~ or else their sting is painless.  In our study of bees in Westchester County, NY gardens, Calliopsis, Agopostemon and Andrena bees are solitary, soil nesters.  Solitary bees tend to be very docile, as they don't have a colony to defend.  Lasioglossum and Halitctus bees are eusocial, soil nesters.  These are the 'sweat bees' ~ so called because they have been seen drinking sweat from humans (probably to get some salts).  Although they sometimes (rarely) sting humans, their sting is rated a very low 1.0 on the Schmidt Sting Pain Index, making it almost painless.
  3. Yellowjacket colonies build in size over the gardening season.  Right about now is when they reach their maximum size, and when they're most noticeable and problematic to gardeners.
  4. Multiple stings suggest yellowjackets.  Honey bees can only sting once.  Bumblebees can sting more than once (and may also nest in abandoned rodent burrows in the ground).  But, most people would be able to recognize a large bumblebee, rather than be left wondering what stung them.
So ~ you have yellowjackets.  What can you do?

In my experience and from my reading of the literature, you have two practical options.
  1. Leave the nest alone.  The fall is the time of the year when new males and queens will emerge and mate.  The males, with their 'live fast, die young' approach to life will soon bite the dust after mating.  The newly-mated queens fly away to a protected site, where they will spend the winter.  The nest will be abandoned, and will start to break down over the winter.  Nests are almost never used again.  You will not have the same yellowjacket problem, in the same nest, next season.  If you do decide to leave the nest alone, make sure  you mark off the area ~ so that you don't forget where the nest is, and so that visitors to your yard know to avoid that area.  If you have young children (who would not abide by a 'keep out' directive), if you have large pets (who might trigger an aggressive response by the yellowjackets) or if you simply can not stay out of the area, leaving the nest alone may not be an option.
  2. Use a commercial wasp or hornet pesticide, during the coolest part of the day.  Wasp sprays tend to be highly pressurized, so that you can spray them at a distance from the nest entrance.  Spraying during the coolest part of the day means that the yellowjackets will be less able to mount a defense against you.  It will be simply too cold for them to move with gusto.  Still, by spraying the nest, you do risk getting stung.  Make sure to spray the entrance of the nest.  This will get the yellowjackets as they fly in and out of the hive.  It will also do the best job of dousing all that reside within.  Don't light your way using one flashlight, which you aim at the entrance of the nest.  This could create a beacon that tells the aggressors exactly where to fly, to protect the nest.  I would wear two layers of thick clothing (jeans with leggings underneath, a tee shirt, with thick sweatshirt or jean jacket over top).  I would tuck my pants into my socks and my shirt into my pants.  This will prevent a yellowjacket from getting under your clothing, where you could be repeatedly stung. Cover your neck, hands, head and eyes, as well.  Yes, you may look like Ralphie from 'A Christmas Story', but better safe then sorry ~ right? [I stand corrected.  It was Randy, and not Ralphie, who was bundled up in winter wear.  Edited September 20, 2013.]

When I'm asked to treat a yellowjacket or bald-faced hornet nest, this is a pretty fair representation of how I dress for battle.

Other options I've seen, but don't particularly like for dealing with a fall fest of yellowjackets include:
  1. Trapping the yellowjackets.  At this point in the year, when the nests have built up to a large number of residents, I don't think that trapping will solve the problem.  It may, however, help keep yellowjacket numbers down, early in the gardening season ~ next year.  Use them earlier in the season, if you decide to employ a trap.  Waiting until the fall is likely too late to do any good.
  2. Vacuuming them up, in the evening, at the site of the nest.  Hmmm.  I just can't see this one working very well.  I'll let the author of that idea try it out, and let me know how it goes. [Edited September 20, 2013: the one reference I read about vacuuming up the yellowjackets suggested that it could take two or more hours to treat the large nests that are characteristic of the fall season.  Standing on top of a yellowjackets' nest for two hours, to hold a vacuum at the nest entrance and try and suck up all that come out?  It still doesn't sound like a practical idea to me.]
  3. Pouring soapy water down the entrance of the nest, also at night (when temperatures are cool).  Soapy water helps to break down the waxy cuticle of an insect's exoskeleton ~ but I just can't see this being an efficient way to deal with yellowjackets.  Once again, I'll let someone else try this one out, and let me know how it goes. [Edited September 20, 2013:  I've had several people tell me that soapy water, followed by boiling water poured down into the nest, has worked for them.  They note that when performed during the day, they did get stung.  Soapy water, alone, is not likely to work ~ as soap works best against small, soft-bodied insects.  The soap literally degrades the waxy cuticle of an insect's exoskeleton, the same way it helps wash away grease on your dishes.  Thick-bodied insects aren't as prone to soapy water as are things like aphids or thrips.  But, followed by boiling water ~ it likely does the trick.  The soap, acting as a surfactant, will help the boiling water spread thoroughly throughout the nest.  Because you'll have to get up close to the nest to pour in the soapy water, and then the boiling water, prepare for a high probability of agitated yellowjackets.]
To prevent future infestations, consider whether or not you have a rodent problem in your yard.  Often, abandoned rodent burrows are used as nests.  Fill the burrows, or focus on the rodent issue, and the yellowjacket problem will likely subside.

Some great references on yellowjackets include: