Legislating Behavior and #Beewashing

Bees have been on my mind an awful lot, lately. And that's saying something ~ considering that I'm an entomologist who has spent a lot of time studying the bees the live in our gardens and parks, as a way to better understand how to garden in ways that protect (rather than harm) these beautiful jewels of the garden.

One of my favorite bees:  Agopostemum sp. (probably, Agopostemum virescens) on a sunflower in Spokane, WA.  Photgrapher:  Gail Langellotto

So, on a normal day, I think about bees quite a bit.  But lately, everywhere I turn, bees ~ and issues related to their conservation and protection ~ have been hitting me upside the head.

First, there was the news that Jeff Reardon (D-Portland) is considering legislation to restrict home gardener use of four neonicotinoid insecticides:  dinotefuran, imidacloprid, clothianidin and thiamethoxam.  Master Gardeners keep asking me what I think about this development, and our discussions have been really interesting.

Second, I received an email announcing that the Bayer Bee Care Tour is coming to Oregon.

It can be tough to write about pesticides and bees in such a public space.  There's so much rhetoric surrounding colony collapse disorder, bees and neonicotinoids that it can be difficult to separate sound science from sound bytes.

This is made even more difficult by the reality that sound bytes are easy to digest and even easier to propagate via the internet.

• Sound byte:  neonicotinoids are killing honey bees.

By contrast, what we learn from sound science is usually much more complex and nuanced to communicate.

• Science byte:  Many insecticides can have harmful impact on honey bees.  These harmful impacts are most apparent when pesticides are mis-used, such as being applied to plants in bloom or to areas with a lot of bee activity.  In addition to insecticides, habitat loss and development, the variable nutritional quality of a bee's diet, parasites and pathogens are implicated as being major threats to honey bee health.  It seems that honey bees are so immune-compromised, that adding on one additional stressor can have dire effects on hives.  But, if we focus on the impact of pesticides on honey bees, it's important to point out that beekeeper applied pesticides (to keep Varroa mites an other honey bee pests at bay) are a major source of honey bee exposure to pesticides.  It's not just growers applying pesticides to crops (although, this is also an important part of the picture that stresses bees).  But even if we take pesticides applied to crops out of the picture, honey bees would still be exposed to pesticides.  Bee keepers are really challenged to keep healthy hives with so much pest pressure on honey bees (mites, diseases, fungi), and so few options for control.  And, I could go on and on and on . . . because the story really is so complex.

But, I want to write about these things, because a major goal of my program is to ensure that home gardeners are informed and educated about current topics ~ so that they can make the best decisions for their particular gardening situation.  Knowledge is power, right?

So what do I think about the potential ban on home gardener use of neonicotinoids?  Well, it's complex (of course!).  I see value in neonic insecticides, and I have concerns about neonic pesticides.

Here is where I see value in neonics:

1.  I like that they can be applied as a soil drench, which is a much easier pesticide application method for homeowners who need to treat a large tree or shrub, compared to a foliar insecticide spray.  I have seen too many bad examples of hose-end sprayer applications of insecticides to trees (e.g. homeowners standing underneath the drip line of the tree they were treating, or not being aware when the pesticide runs out ~ so that they continue to spray the tree with their hose ~ basically washing off the pesticide that they just applied).  Soil drenches, by comparison, are easier for most homeowners to apply in a way that does not expose them to the toxin, and in a way that may better target the intended pest ~ rather than dousing all insects that are in the canopy.
2. Neonics have been a useful tool in protecting at risk trees (ash trees in the Mid-west) and ecosystems (hemlock forests in the NE) from large scale loss because of emerald ash borer or hemlock wooly adelgids, respectively.  In these instances, the products have been a useful tool in an overall integrated pest management approach to protect trees.  The IPM approach relies heavily on monitoring and quarantine in these instances.  The pesticides are not the first tool pulled out of the toolbox ~ but they are one aspect of an overall approach to protecting these trees.  And, these trees are pollinated by wind, and not insects ~ which reduces risk to bees and other pollinators.

Here is where I have concerns about neonics:

1. My biggest concern over the last few years has been that most homeowners don't understand how persistent a neonic can be in a tree or a shrub.  I've written about this in a past blog post, and I've lectured on this extensively over the past few years ~ trying to raise awareness of this issue.  But, if you're reaching for a neonic in response to a one-time, ephermeral issue with aphids in your trees ~ you're reaching for the wrong product.  Better yet, many aphid outbreaks, if allowed to run their course, tend to disappear on their own.
2. Honestly, many plants are fairly robust to pest damage.  The plants often recover.  A plant's tolerance for damage is often less than a gardener's tolerance for damage.  But, neonics are so easy to apply as a soil drench, that I worry that folks reach for them too often ~ as a quick and long-term way to keep their trees, shrubs and other woody plants free from damage.  This isn't IPM.  IPM is a well-thought out and informed approach to pest management that makes optimal use of all IPM tools, so that pesticide applications are reduced, targeted and effective.  
3. I of course am concerned with the data that is accumulating on sub-lethal impacts of neonics on bees who gather nectar and/or pollen from flowering trees or shrubs that have been treated with a neonic.  The low doses of pesticide the bees get from the blooms is not enough to kill them, but it can be enough to change bee behavior in a way that has negative impacts on the hive.

What do I think about the proposed ban on neonics?  I have mixed emotions.

1.  If banned, I guess I wouldn't have to worry about emphasizing the potential for long-term persistence of neonics in woody plants.  It wouldn't be a matter of educating homeowners to make better decisions about the products ~ because homeowners wouldn't have a choice.
2. But ~ if banned, I'm really concerned that homeowners will instead reach for pesticide products that are broad-spectrum, foliar insecticide sprays.  These sprays have a much greater potential for harm to human health.  And, if mis-applied (such as the hose end sprayer example I gave earlier), these sprays could run off of the tree canopy and do real environmental harm ~ not to mention their broad impacts on insects that would be contacted by the spray.
3. And, because of the value demonstrated by neonics in protecting at-risk, wind-pollinated trees, I do see a role for neonics in an IPM approach to plant protection.

What about my thoughts on the Bayer Bee Tour?

Well, the original stops on the Bayer Bee Tour included 'corn belt states'.  The tour appears to have been held from Feb. 26th-April 3rd, 2013.  But now, the Bayer Bee Tour is making its way to Oregon.  How curious, that the timing of a new stop on the Bayer Bee Tour happens so soon after Jeff Reardon's proposed legislation.

I'm not against Bayer ~ or any agrochemical company.  Bayer helps to develop new pesticide products that can be important tools in an IPM approach to plant protection.  And ~ before you jump on me for that last sentence, consider that one of the reasons that bee keepers are so challenged by Varroa mite is that there hasn't been an investment in developing new products for managing mites in bee hives.  Growers need tools to manage plant pests in the context of a well-planned IPM program ~ and without access to high quality tools, there is the potential for increased use and reliance of inferior tools.

I'm instead annoyed that the Bayer Bee Care Tour has rented facilities at major universities (Ohio State, Univ. of Illinois, Iowa State, University of Nebraska, University of Minnesota . . . and now, Oregon State University), and marketed it in a way that suggests that OSU is a collaborator on the tour.  Although completely within their right (these facilities are available for any group to rent and use), I worry that their Bee Tour announcement promotes the false impression that these stops have been planned with and endorsed by the Universities.  When in actuality, the entomologists I've talked to at Oregon State were largely caught by surprise by this upcoming Bayer Bee Tour stop, and were only called after the fact by Bayer to see if they would participate in a panel discussion (most, if not all, have said 'no').

It seems that the more open and inclusive approach, if the goal is to align Bayer's bee protection efforts with what is going on at Land Grant Universities, would be to invite Oregon State researchers to the table from the beginning ~ rather than trying to tack folks on as an afterthought.

Neonicitonoids offer LLLOOONNNGGG Term Protection Against Pests

One group of pesticides that I have been devoting more and more time to in my Master Gardener training classes is the neonicotinoids. This group of pesticides received quite a bit of news this past week, as news outlets reported on two studies that link bees' declines with neonicotinoids.

Imidacloprid is perhaps the most common neonicotinoid pesticide available to home gardeners, as it was the first neonicotinoid to gain widespread use (Mullins 1993). Imidacloprid is a systemic insecticide. When applied as a soil drench or soil injection, it is absorbed by the plant's root system, and distributed to different plant tissues via the plant's vascular system. Imidacloprid can also be applied to plant leaves. This is known as a foliar application. In general, soil applications of imidacloprid take longer to work against insects, compared to foliar applications. However, soil applications of imidacloprid are effective for longer, compared to foliar applications.

There are two primary advantages of using a systemic insecticide, such as imidacloprid, against insect pests.

• First, imidacloprid is highly specific to insects. Imidacloprid is thus less likely to have negative effects on humans and other mammals, compared to other pesticides - such as the organophosphates or carbamates.

• Second, since soil applied imidacloprid is taken up by the plant's roots and incorporated into plant tissues - by definition - only a pest of that plant will get a dose of the insecticide. An insect has to feed on the plant to get a dose of the pesticide. Sitting on the plant is not enough to get a dose. This is one advantage of soil applied systemics, compared to insecticide sprays. With broad spectrum insecticide sprays, every insect in the path of the spray - whether they are the target pest, or a beneficial lacewing - gets a dose of the insecticide. Systemic pesticides diminish these 'non-target effects'. Of course, there is the issue of systemic insecticides being translocated to the nectar and pollen of plants. I'll cover this issue in a future post. Nonetheless, I'll mention here that one way landscape managers try to reduce the impacts of systemic insecticides on bees is by limiting their application to wind-pollinated trees - such as hemlocks.

Other potential advantages of soil-applied imidacloprid include:

• They are easier to apply to trees and large shrubs, relative to foliar sprays, and

• They offer long term protection against pests. In fact, you can often spot those pesticides that are likely to contain imidacloprid as an active ingredient, by looking for phrases such as '12 month control' or 'season long control' on the container.

However, there is much to learn about the long-term persistence of soil applied imidacloprid in trees and shrubs. In fact, the data that is available suggests that long-term persistence may really be LLLLOOONNNNGGGG term persistence.

• Szczepaniec and Raupp (2007) found that toxicity persisted, and pests were absent, up to three years following the application of imidacloprid to potted cotoneaster. It is important to note that the researchers did not sample foliage or look for pests in year four. They stopped their assays three years following the application of imidacloprid.

• Cowles and Lagalante (2009) found that a single soil injection to hemlock can provide between 5-7 years of pest protection, and that imidacloprid was detectable up to 8 years after application. After 5 years, the metabolite imidacloprid olefin was more abundant in tree tissue than imidacloprid. Although the authors of this report note that the olefin metabolite is much less toxic than imidacloprid, Nauen et al. (1999) report that the metabolites (including olefine) of imidacloprid retain toxicity to at least some insect pests.

• Dilling et al. (2010) found that trunk injection of imidacloprid in hemlock trees provided protection against hemlock wooly adelgid for 3-5 years.

• Webb et al. (2003) also found that a soil drench of imidacloprid protected hemlock trees from hemlock wooly adelgid for almost three years - the extent of the assays in this study.

Now, I'm not writing this post to be anti-pesticide or anti-imidacloprid. In fact, imidacloprid has great potential as a tool that ecologists and land managers can use to save ancient hemlock forests from the invasive insect, hemlock wooly adelgid. This insect is having large-scale, ecosystem level effects that threaten unprecedented hemlock loss (Orwig et al. 2002). If we love hemlocks and hemlock forests, then it makes sense to consider imidacloprid as one tool that can be used against hemlock wooly adelgid, as part of a comprehensive integrated pest management plan. Remember that hemlocks are wind pollinated, thus lessening the potential negative impacts of imidacloprid-treated trees to bees.

Instead, I'm writing this post because I worry that too many home gardeners see the advertisement of '12 month control' on the front of the label, and think 'hmmm . . . . why purchase a product that can give me short term control, when I can get one with really long term control? That seems like the best buy!'

If you are having a short-term, one-time problem with aphids on your rose bushes, I'm not sure that imidacloprid is your best choice. In fact, for short-term, one time pest problems on any plant, I'm not so sure that imidacloprid is the best choice. Thus, I wanted to write a post that points out that the long term protection advertised may be RRREEEEAAAALLLLLlllllyyyyyy long term protection.

It's interesting to note that only one of the studies that I listed (Szczepaniec and Raupp (2007)) looked at the long-term persistence of imidicloprid in an ornamental plant. It's also interesting to note that many of these studies could detect imidacloprid (via bio-assay of pests or chemical assays for the active ingredient) up through their last sampling date. Thus, there is clearly more to learn about the persistence of imidacloprid in home gardens.

Are soil-applied systemic insecticides the best choice for pest problems in the home garden?

Are annual applications necessary?

I can't answer these questions - but I think they're important questions to ask.