Tuesday, December 31, 2013

Six Ways to Reduce Your Pesticide Use

It's the New Year ~ that time of year when many people resolve to do something better in the coming year, than perhaps they did in the past year.  Most resolutions have to do with getting healthier in some way, shape or form ~ whether it our physical health or our financial health.

In case your resolution has to do with your garden's health, I thought I would offer up XX ways that you can work towards reducing your pesticide use.  Some of these approaches require nothing more than a shift in perspective.  Others will take more time and effort.  But all are capable of having the effect of reducing pesticide use ~ which is generally good for the health of our environment, pets and families. 

1. Stop acting like organic pesticides aren't pesticides.  Many people believe that anything labeled with the term 'organic' equals 'no pesticides'.  They mistakenly believe that organic produce hasn't been sprayed with pesticides.  They mistakenly believe that they can use a pesticide labelled as 'organic' with total impunity.  And unfortunately, some folks tend to use more pesticide, simply because the pesticide is labelled as 'organic'.  As a general rule, pesticides ~ including organic pesticides ~ are formulated to kill or deter something.  Stop spraying it everywhere, thinking it's safe.  All pesticides should be used judiciously and thoughtfully ~ taking care to limit use only to when and where needed.
Organic pesticides are still pesticides ~ formulated to kill something.  Use judiciously.

2.  Make peace with spiders.  I adore spiders.  I think they're absolutely adorable!  If you have a chance to look at them under a microscope, you'll see that they're cute and fuzzy ~ not unlike a teddy bear.  And, they're great allies in natural pest control.  But I get that some people are seriously arachnophobic.  If you simply can't tolerate spiders, please don't reach for a pesticide.  The thought simply breaks my heart.  Instead, try to get the spiders to relocate.  If they're on your porch, try installing an ornamental porch bracket that will take away anchor points from web-building spiders.  Or, consider installing a yellow-hued porch light.  Yellow lights attract fewer night-flying insects, which will attract fewer hungry spiders.
Lynx spider in an azalea blossom.
Porch brackets can take away web-building sites for spiders.  Source of image:
3.  Build diversity into your garden.  Diverse gardens, with an array of plant families, shapes, colors, sizes, and bloom times also tend to have a diversity of insect herbivores (sometimes called pests).  But, the trick is that even though diverse gardens tend to have a greater diversity of pests, these pests tend to be at lower abundance!  Why?  It may be that a diversity of natural enemies keep them in check.  It may be that a diversity of plants keeps them from exploding in abundance on a single plant type.  Or, it's more than likely a combination of these factors.

Marion Garden in Salem, OR.
Marion Garden in Salem, OR.

4.  Rethink your approach to early-season lawn weeds.  Are dandelions really all that bad?  Not if you love bees.  Our research has found that gardeners who tolerate early-season lawn weeds are likely to have a greater diversity of bees than those who keep totally pristine lawns.  Why?  In early spring, very few flowers are in bloom that offer spring pollinators access to nectar and pollen.  Dandelions are one such flower that helps early season pollinators get a jump on their season.  If you want to keep your lawn dandelions in check, try to dig this perennial weed out, so that you get the entire taproot.  Target young dandelions before they set seed and before they have a chance to grow a large taproot that will nourish them for many years.  Make sure your lawn is healthy and full, to crowd out dandelions.  Or, plant a dense flower bed, with no bare spots where dandelions can flourish.  Or, adjust your tolerance, and recognize that a dandelion isn't the worst thing that could grace your garden.  Invasive plants, such as cornflower (Centaurea cyanus), English Ivy (Hedera helix) or butterfly bush (Buddleia davidii) are much more damaging to the environment and to local economies than are a few dandelions.  It would be much better to target your weed-hating energy towards these plants, than towards dandelions.

5.  Take regular walks in your garden.  This will help you notice when things 'don't look quite right'.  Regular walks in your garden are not only good for the soul, but their good for an IPM approach to managing pests in your garden.  When you notice that something doesn't look quite right, stop and take a closer look.  Often, you'll catch a pest problem in its early stages ~ when it will be easier for you to manage the problem.  Problems caught early usually require fewer (or no) pesticide, compared to those that are allowed to grow out of control.  A corollary to this suggestion is to keep a garden journal.  This will help you track (and remember) the seasonality of pest problems in your garden, so that you'll be better poised to respond quickly.

6.  Talk to the professionals who maintain your lawn and garden.  Ask them if they use an IPM approach to pest management.  Ask them if their staff are up to date on certifications and continuing education requirements.  Ask them what the major pest issues are in your lawn and garden.  Discuss non-chemical options for managing these pests.  If they don't know about IPM, and aren't aware of non-chemical options for dealing with common garden pests, you might want to look for a better-educated lawn care company.

Tuesday, December 24, 2013

During this Season of Giving: Six Garden-Focused Organizations to Consider

In my job, I've been lucky enough to meet so many folks who are passionate . . . and I mean PASSIONATE in their belief that they can help build a better world through gardening.  Some work to feed their neighbors, some work to teach the young, and others work to make gardening accessible to those who don't know how to garden, or those who need help starting a garden.

If you're thinking about making a year-end donation to a garden-focused organization, here are six that could use your help.

I've worked with all of them, in some capacity or another.  Some, I know through grant programs that I've judged.  Others, I know because Master Gardener volunteers support their efforts.  I've sat on the board of one, and know most others from our mutual work on the Oregon Farm to School and School Garden Network.  One, I've made my life's work.  Most of them are too small to appear on, but if a rating does exist, I've posted it next to the organization.

Growing Gardens:  This amazing organization works with volunteers to install raised-bed vegetable gardens in the yards of low-income households.  Those in apartments or with limited space receive container gardens.  Recipients are then supported for 3-years, via a comprehensive educational program (that teaches them how to maintain and use their garden), seeds and starts, and access to garden mentors.  This past fall, they just installed their 1000th garden!

Lettuce Grow:  The Lettuce Grow ('Let Us Grow') Garden Foundation works to install organic vegetable gardens in correctional facilities across Oregon.  In doing so, they help to keep the correctional facility food budget low, while providing healthy and fresh produce to inmates.  Lettuce Grow also facilitates educational opportunities to inmates who work in the garden, by working with the Oregon Food Bank to deliver the Seed to Supper curriculum and by working with OSU Extension to deliver the Master Gardener curriculum in correctional facilities.  Upon successful completion of the Master Gardener curriculum, students earn a Certificate of Home Horticulture ~ a valuable job credential that is of value upon their release.  However, perhaps the most important benefits of the garden programs are their therapeutic effect.  Working the land is healing ~ especially in the high stress environment of a correctional facility.  And, education has the power to create positive social change ~ perhaps more than any other program that I know.  To me, Lettuce Grow offers hope in a place that may often seem hopeless.

Oregon Food Bank:  The Oregon Food Bank partners with OSU Extension to deliver a 5-week, comprehensive gardening course called Seed to Supper.  This curriculum is taught to low income individuals and families ~ teaching them how to grow their own food and to use the harvest in freshly-prepared and healthy meals.  Oregon Food Bank has 3 out of 4 stars on Charity Navigator, with a 70 out of 70 for transparency and accountability, and with 94% of their budget being spent directly on programs.

Food Roots:  I first learned of Food Roots, when they applied for a grant that OSU was offering for school and community gardens.  I was impressed with their application, and even more impressed when I visited their community and school gardens throughout Tillamook County.  They work to support a vibrant food system across Tillamook County ~ via their support of community and school gardens, educational outreach, and micro-enterprise endeavors.  Right now, they're holding a drive to raise funds to build three high-tunnel hoop houses that will be used to hold training classes on how to grow a diversity of fruits and vegetables in the cool climate of the North-Central Coast.  Honestly, I'm amazed at what Shelly Bowe has done in a few short years.  She is a force of good!

School Garden Project of Lane County:  This organization teaches kids about gardening, through in-school lessons and after school gardening clubs.  They assist schools in putting in fruit orchards, or starting a cafeteria composting program.  They also also created a garden-based curriculum for use in elementary schools.

OSU Extension Master Gardener Program:  I'd be remiss if I didn't mention the organization where I work.  We work to train volunteers, who then go on to share what they learned about sustainable gardening with others.  We currently have over 4,000+ volunteers who field close to 200,000 gardening questions each year.  Surveys show that our volunteers and our programs make a difference and promote more sustainable gardening practices.  For example, after participating in our programs or using our services, our clients report that they will decrease or eliminate their pesticide use (68% of those surveyed), work to attract beneficial insects to their gardens (64%), or that they are more tolerant of insect pests (58%) or early flowering lawn weeds (60%).  Those with pest problems report that they intend to switch to more pest resistant cultivars (75%), further decreasing the need for pesticides.  Your dollars can be allocated to support the statewide Master Gardener Program, or to any of the county Extension offices in Oregon with active Master Gardener Programs.  Those few counties with online donation pages are listed, below ~ but you can also go into your local Extension office to make a donation to your local Extension Endowment Fund or Master Gardener Association Chapter.

Wednesday, December 11, 2013

Will this cold snap help keep insect pests down, next season?

It's a beautiful, spring-like day today in Corvallis ~ a welcome relief from our recent spate of freezing weather!  Being half-Filipino and half-Italian, I have a propensity for sunlight etched into my genetic code.  But, I took solace in this recent round of cold weather, by imagining freeze-induced die-offs of key insect pests, in epic proportions.  

How might this current cold snap be wreaking mass entomo-cide on some of my most challenging garden pests? It likely varies across insects.

Azalea Lace Bug (ALB):  I couldn't find any data on the cold tolerance of ALB, other than secondary citations that the bug is hardy to cold weather.  The original publication is Neil, JW. 1985.  Pest-free azaleas can be a reality. J. Azalea Soc. Am. 7: 25-29, but I can't get my hands on that publication.  From the title and the journal, it seems that it would be an anecdotal report that ALB can survive extended periods of cold weather.  This isn't a surprise, since the insect overwinters in the egg stage, the egg is layed INSIDE leaf tissue (offering the eggs protection from cold, predators and parasitoids), and that the egg is covered by an adhesive goo that further provides protection from cold and natural enemies.  It's unfortunate, but this cold snap is unlikely to put a huge dent in ALB populations that we might see next season.
Azalea lace bug adults are about 1/4 of an inch from head to tip.  Start scouting your rhododendrons and azaleas for the first generation of young nymphs, as early as mid-April.  The first clutch of eggs generally hatches in early May, but could be earlier or later, depending upon local weather and other environmental conditions.  Photo Credit:  Robin Rosetta.  OSU Department of Horticulture and North Willamette Research and Extension Center.
If you want to see whether or not your rhododendrons or azaleas have overwintering eggs in them, you can scout your plants anytime between now and the April.  Look for signs of egg-laying damage, on the underside of the leaf, along the mid-rib.  The eggs are super-tiny, but are covered with a tiny brown speck (the adhesive I mentioned, earlier).  Robin Rosetta's fact sheet on ALB has a magnified photo of the eggs.  If you see signs of eggs in your rhodies or your azaleas, mentally or physically make note of which shrubs carry ALB.  Make sure to monitor those shrubs for the first generation egg hatch, anytime from mid-April to mid-May.  One of the best things you can do for season long control is to knock back that first generation of nymphs, so that they don't become adults who will lay more eggs in your rhodies.

Chemical controls are available, but some people have tried to use strong jets of water to knock the nymphs off of the plants.  Whether you use an insecticide or jets of water,  it's important that your shrub canopy is 'open' enough so that your control measure actually reaches the nymphs.  The nymphs feed on the underside of leaves, and in dense rhodie canopies, you will have a harder time reaching the nymphs with an insecticide or a jet of water, compared to a more open canopy.

If that first generation gets past you, ALB will be much more difficult to control.  The bugs are long-lived (by insect standards), and as time passes, you'll start to see an overlap of generations (egg stage, nymphs, adults all occurring together on the same plant).  Control measures, such as chemical controls or streams of water, will help control the nymphs ~ but will be less effective against other life stages, particularly the egg stage.  Keep in mind that chemical controls will also negatively impact natural enemies, such as lacewings, predaceous bugs, spiders and parasitoids ~ all of which have been shown to help naturally suppress ALB populations.

For long term control of ALB, make sure your rhodies are part of a diverse landscape.  Tree canopy cover and other shrubs will help promote spiders ~ one of the main natural enemies of ALB.  Annual wildflowers will provide nectar for green lacewings, which have been shown to help control ALB at a rate of 10 lacewing larvae per shrub.

Brown Marmorated Stink Bug (BMSB):  BMSB are often reported as 'nuisance pests' because they can aggregate in large numbers in your house.  In fact, National Wildlife Federation Senior Scientist Doug Inkley tracked the movement of BMSB into his house, and up to the attic in 2011.  Over the course of 72 days, Dr. Inkley counted 20,116 BMSB in his house!!  You can see from the graph, below, that there was a progressive movement up and into the attic.  Because BMSB overwinters in protected structures ~ like your house ~ this cold snap is unlikely to result in massive die-offs of this insect.

Dr. Doug Inkley tracked the movement of BMSB into his house and up into his attic over the course of 72 days.  Image source:
In addition to being 'nuisance pests' in your house, BMSB can also be a real problem for gardeners.  BMSB use their piercing-sucking mouthparts to probe fruits and seeds.  They can damage pea pods, berries and stone fruits in the garden.  Unfortunately, for home gardeners, there aren't a lot of control options.  Biological controls aren't generally successful, because BMSB have a noxious scent that make them unappetizing to many predators.  Chemical controls are available for this pest, but at best ~ these options provide 'temporary relief' rather than long term suppression.  From our friends back east, we've learned that you just kind of learn to live with BMSB.  It becomes a 'new normal' in the garden.
Brown Marmorated Stink Bug Adults survive the winter by hiding out in attics, barns and other protected structures.  Photo Source:  Brown Marmorated Stink Bug website, OSU Department of Horticulture
Spotted Wing Drosophila (SWD):  We're still not sure how SWD overwinters.  On a sunny, winter's day, you can catch SWD in monitoring traps.  This suggests that the fly overwinters as an adult ~ but it is also quite possible that other stages are present in the winter.  In any case, the fact that we can find SWD in the adult stage, in the winter, bodes well for a massive freeze-induced die off of this berry-feeding fly.
In fact, there was a recent paper published by Danny Dalton (OSU) and colleagues, on the cold-tolerance of SWD, and how adults and pupa react to a 7-day 'freeze' event (Dalton et al., 2011).  And, their data suggests that these generally low winter temperatures, and the recent Willamette Valley, OR 'freeze' event bode well for SWD control.

If SWD are kept in conditions below 50 degrees F for about 30 days, they are super-susceptible to a cold snap.  However, if SWD are kept in conditions above 50 degrees, there are at least some adults that may survive a harsh cold snap, such as the one we've just had.

To see if we've been above or below the 50 degree threshold, I plotted the weather history for Covallis, Oregon over the last month or so ~ and marked on the plot where the threshold is for the 50+ degree F 'safe zone' and the below XX degree F 'freeze zone'.   And it looks like we have plenty of days where the mean temperature was below the 50+ degree 'safe zone', preceding our 7 day 'freeze zone' temperatures.  All of this suggests that this recent weather will help gardeners and growers with Spotted Wing Drosophila populations next season ~ a welcome relief for berry growers and berry lovers across Oregon.

Of course, it's important to point out that the Dalton et al., (2011) experiment was conducted in laboratory growth chambers, with very little organic material that the flies could use as shelter from the cold.  In 'the real world', the flies probably have many more opportunities hunker down from the cold ~ and thus probably have a greater buffer from the cold than my graph might suggest. 

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:

Wednesday, August 14, 2013

Does Wearing Perfume Confuse Bees?

This weekend, the following snippet in the Oregonian's Home and Garden section caught my eye.

Another reason to avoid artificial fragrance: It can confuse bees. Bees are vital to the natural world  thanks to the important work they do to pollinate flowers. They are attracted to the sweet-smelling scent from actual flowers, and are also attracted to artificial scents found in body washes, perfumes, shampoo, air fresheners and scented candles. This confusion by bees can lead to fewer pollinated flowers. One way to help is to choose fragrance-free options whenever possible.

-- Danny Seo, eco expert, Universal Press Syndicate

Is this really true? Will my locally-sourced and produced lavender soap draw bees away from the real deal?

As someone who uses lavender-scented soap and a kukui-nut scented lotion, could I be responsible for the current pollinator crisis?

Not likely. Bees find flowers by scent, but they also orient by sight. And, bees are remarkably good at 'remembering' which floral visits were profitable and which were a waste of time.  In tests of honey bees, they performed remarkably well at discriminating among similar scents, to hone in on the scent that was previously associated with a 20% sucrose reward.  Of the 1848 odor pairs, the bees were able to choose the 'reward' scent' 97.0%  of the time (1793 odor pairs). Only seven odor pairs (i.e. 0.4% of all odor pairs) were not distinguished by experimental bees trained to a given scent.  The other 2.6% of scent 'failures' (48 odor pairs) could be attributed to a single poor-performing bee.

Other studies of solitary bees have found that you can get a response from their antennae to certain scents, but that this doesn't mean that they'll visit the source of the scent.  Visual stimuli (how a flower looks) and previous floral rewards (if a flower gives nectar and/or pollen) matter.

So . . . even if we use scented shampoos, lotions, etc., we don't really look like flowers, and we probably don't provide a nectar reward.  Bees are unlikely to be fooled.

My favorite test of this topic was presented at the 2009 annual meeting of the Entomological Society of America, by my friends John Carlson  and Mark Fox.  The abstract of their presentation, entitled 'Is that a person or a flower?  Experimental evaluation of the standard recommendations given by physicians to venom-allergic patients regarding foraging Hymenoptera'.
Could this shirt put you at risk? Photo Credit:  Dayna Inc., the UnHawaiian Shirt Company.

Physicians give patients with life-threatening allergies to Hymenoptera venom, advice regarding avoidance of defensive stings as well as avoidance of foraging workers. Some of this advice is in contrast to recommendations given by USDA and other organizations that employ entomologists: avoid wearing bright colors, floral patterns,and perfume that might attract foraging insects. The likelihood of a bee or wasp to alight upon clothing was tested in haphazardly chosen locations around New Orleans, LA over the summer of 2009. Dark clothing and bright, floral patterned clothing were placed on the ground and observed for 10 minutes. Perfume was applied to all clothing for a second 10 minute observation period. Control plots were observed during each replicate to ensure that foraging Hymenoptera were active on flowers at the location. No species from which allergy has  been reported alighted on any article of clothing for the duration of the study. These results were expected based on the known sensory cues used by social Hymenoptera in locating food. In light of these findings, venom-allergic patients should not be advised to avoid perfume or bright clothing, especially because dark clothing has been associated with stings from workers defending honey bee colonies.

Mark and John used perfumes with the highest concentration of natural floral scents.  They purchased the gaudiest floral shirts they could find ~ as well as shirts with 'realistic' looking flowers.  Alas, the shirts did not receive any bee or wasp visitors.

Tuesday, March 19, 2013

Biodiverse Gardens are More Pleasing to the Eye

Despite publishing a scientific paper entitled 'Small scale additions of native plants fail to increase beneficial insect richness in urban gardens', I really am a huge fan and proponent of native plants and biodiverse gardens.  I just have a sense that the benefits of native plants (especially smaller shrubs and annuals) are oversold to home gardeners.  Not all native plants will use less water, better resist pests, or best attract wildlife.  And, gardeners are often left with the impression that they can install a few native plants to support local wildlife.  However, our results suggest that additions of 200-250 plants would be needed, to increase bee, butterfly or beneficial wasp richness by one species.

Given that a few plants won't yield strong benefits to native biodiversity, what type of gardening approach can help conserve wildlife?

A new paper by Petra Lindemann-Matthies and Thomas Marty (Does ecological gardening increase species richness and aesthetic quality of a garden.  Biological Conservation Volume 159,March 2013, pp 37-44) provides strong evidence that a whole gardening approach gets results.

They surveyed 36 gardens in Zurich, Switzerland, and scored them for the presence or absence of the following ecological features: 

  • ponds (provide habitat for amphibians, aquatic insects, aquatic plants)
  • flower meadows (provide nectar and pollen to a variety of beneficial insects, and host rodents that are food for birds)
  • dry walls (provide nesting sites for beneficial insects, or insects that birds feed upon)
  • nettle plots (provide nectar and pollen to a variety of beneficial insects)
  • nesting sites for wild bees and birds
  • decomposing piles of wood (provide habitat and nesting sites for a variety of beneficial insects)
and the following gardening practices:
  • frequency of lawn mowing
  • use of synthetic fertilizers
  • use of pesticides
  • frequency of weeding
Bee House
A 'bee barn' at the Marion Garden in Salem, OR.
Marion Gardens
Beneficial Insect Garden at the Marion Garden ~ a demonstration garden of the Marion County Master Gardeners.
They created an 'ecological gardening' score for each garden, by assigning a '1' to beneficial practices (e.g. rarely or never using pesticides) and a 0 to non-beneficial practices (regular use of pesticides).  They then counted the number of plant, fungal and animal species within each garden.

Here is the good news!  Gardens with a higher 'ecological score' were more biodiverse, took less time to manage, and were judged more aesthetically pleasing by neighbors, compared to gardens with a lower 'ecological score'.

In fact, 67% of the variation in biodiversity among gardens was a result of the 'ecological gardening score'.  Only 35% of the variation in aesthetics was a function of the ecological score of each garden, which suggests that ecologically-friendly gardening practices have more of a positive impact on biodiversity, than on aesthetics.

You can learn more about ecological gardening practices by visiting Linda McMahan's ecogardening website, or by visiting an OSU Extension Master Gardener demonstration garden.  Locate the garden nearest you by visiting our Google Map of OSU Extension Master Gardener activities.

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