Pesticides in the News

Pesticides in the News

Randy Oliver
ScientificBeekeeping.com

First Published in ABJ in August 2019

Our beleaguered Environmental Protection Agency, tasked with protecting man and the environment, is caught between an unsupportive Administration and a public that is becoming more and more concerned about the effects of pesticides and climate change.

I plan to return to my series on pesticides, but our extreme weather this spring was disastrous for our bee operation, since we were unable to rear queens for splitting our hives after almonds.  As a result, we were also unable to control swarming. We’ve since been working overtime to try to recover our numbers in time to build our colonies up for next year’s almond contracts.  I recently congratulated my son Eric for now being able to claim the title for having the honor of running the operation during the worst season in memory.

That said, in recent months, a few scientific papers and news items of interest have caught my attention.  We may look back on some of them as watershed events that changed the courses of our future.

Revocation of some neonic labels

OK, there was a lot of hoopla about the recent final settlement of a lawsuit by Center for Food Safety (CFS) that has been ongoing for six years, representing plaintiffs CFS, Sierra Club, Beyond Pesticides, Center for Environmental Health, Pesticide Action Network, and four commercial beekeepers, Steve Ellis, Jim Doan, Tom Theobald, and Bill Rhodes.  The settlement brought headlines such as:

Note how the neonics are invariably labeled as “bee-killing pesticides” — it just sorta rolls off the tongue, doesn’t it?  This “victory” actually meant that EPA would accept the voluntary requests from Bayer, Syngenta, and Valent to withdraw their registrations of 12 products containing one or more neonics: 5 containing thiamethoxam, 6 containing clothianadin, and 1 containing imidacloprid.  All were turf or seed treatments, other than Bayer’s “Flower, Rose & Shrub Care” and one foliar product.

None of the neonicotinoid insecticides were banned from use — only a few formulated products, representing a drop in the bucket of neonicotinoid applications, were being allowed to have their registrations expire (and stock on the shelf could continue to be sold for another year).

There are extreme views on both sides of pesticide issues.  I’m more interested in rational discussion as to how farmers can best control pests via sustainable and eco-friendly methods.  For the foreseeable future, pesticides will remain part of that equation.  The neonics live up to many of their promises,  but as one would expect from any neurotoxin, must be applied with caution, and the EPA must follow research findings that indicate that there may be unforseen adverse effects.

Such unforeseen effects are noticed only after a pesticide has been in use for some time, and there are plenty of folk out there looking for any problems due to the neonics.  One recent paper suggests that we need to call for more research on the affects of neonics upon mammalian reproductive hormones.

Practical application: I’m glad to see neonics removed from the homeowner arsenal, due to their potential for problems to pollinators visiting excessively-treated plants.  The lawsuit didn’t change much for agricultural uses, but the public attention helps to keep the pressure on the EPA (although it likely falls upon deaf ears in our current Administration).

Neonics and mammalian reproduction

In a recent study run in South Dakota [[1]], the researchers divided 20 captive pregnant female deer into four groups, and fed them a range of doses of imidacloprid in their drinking water, up to 15 ppb, covering a realistic range for field exposure for the lower doses.  I’ll quote their discussion directly:

Our study provides the first overview of effects of imidacloprid on white-tailed deer. We documented that deer in our experiment avoided imidacloprid-contaminated water. Moreover, we discovered that fawns that died during our experiment had greater concentrations of imidacloprid in spleens compared to those that survived. Fawns with relatively high concentrations of imidacloprid in spleen and genital organs also tended to be smaller and less healthy than those with relatively low concentrations of imidacloprid in these organs. Finally, our study provides support for reduced activity of adult and fawn white-tailed deer with relatively high concentrations of imidacloprid in spleens.

I reviewed the study carefully, including reading their supportive citations and beyond.  I have a number of questions about the study and their analyses; the author to whom I submitted them declined to answer.  So although I can’t yet accept their conclusions wholeheartedly, this study calls for follow-up research.

The question is whether some of our pesticides are causing long-term reproductive harm to wildlife, and perhaps us humans as well [[2]].

The reason is that some of the pesticides used nowadays are neurotoxins or may inadvertently act as endocrine disruptors — interfering with hormones involved in sexual development, cancerous tumors, birth defects, and other developmental disorders.

Practical application: The problem is that we may not notice subtle adverse effects until we’ve caused harm to generations of wildlife or humans.  Hence, although I feel no need for alarmism, we do need to keep a close eye on studies such as the one above.

The Phase out of Chlorpyrifos

One class of chemicals that environmental protection agencies are united in trying to phase out are the acetylcholinesterase inhibitors — the organophosphates and carbamates.  These have been clearly linked to causing problems in childhood brain development (yes, my generation grew up with a lot of it).  Oddly, EPA made a special case for the registration of coumaphos for beekeepers to use in their hives against varroa and Small Hive Beetle.

Chlorpyrifos (an organophosphate, commonly sold as Lorsban® and Dursban®) used to be widely used for home insect control and outdoor residential pest management, and remains one of the most widely used insecticides in the world. It is often the most common insecticide found in bee hives (after beekeeper-applied miticides) [[3]].

EPA has been trying to eliminate its use, but the Trump Administration has appealed.  California is nevertheless charging ahead with a ban.  The ag community is alarmed, since there are a number of pests for which chlorpyrifos is the only effective control product.  We’ll see how this plays out.

Practical application: Once a pesticide has been used for a while, it’s not uncommon that there were unforeseen adverse effects to man or the environment.  Chlorpyrifos started to be used in 1965 — five years before the creation of the EPA — so it’s not surprising that it’s got some issues.  Beekeepers have long dreaded bee kills due to Lorsban, so we can hope that growers replace it with something less harmful to bees.

When a regulatory agency declares that it is going to restrict any product or practice, you can count on there being a loud protest that says that change is impossible.  We taxpayers pay the EPA to weigh the evidence for us, although unfortunately of late, politics has trumped science.

Fipronil Cumulative Effects

Beekeepers got it wrong and right

Back in the late 1990s beekeepers in France claimed that Gaucho, a seed treatment containing the systemic neonicotinoid insecticide imidacloprid, which was being applied to sunflowers, was causing massive colony mortality.  But the case against imidacloprid was weak, since the low levels of the pesticide in nectar or pollen would be rapidly metabolized in a bee’s body (~92% is gone within 48 hours), and thus it appeared unlikely that it could kill an entire colony from foraging on the treated crop.  Nevertheless, public protests against Gaucho occurred, and the registration of its use was revoked.

But there was another seed treatment also being applied to sunflowers at the time (Regent) which contained a different systemic insecticide (fipronil).  The beginning of colony deaths actually better coincided with the use of Regent on sunflowers [[4]].  The colony deaths continued.  Despite the claims by the manufacturers that the treatments were safe for bees, Regent was also banned [[5]].  I searched the Web and found that Regent insecticide appears to still be sold in the U.S., but only for use as a furrow treatment on potatoes, and a treatment for corn seed to be exported outside of the U.S. or its territories.

When I walked in to shoot this photo of hives being used to pollinate sunflowers, the smell of pesticide on the tomatoes in the foreground was intense.  Sunflower pests unfortunately often get a foothold when the flowers open, thus calling for insecticide applications at exactly the worst time for pollinators.

A recent study by Holder [[6]] found that the beekeepers were likely wrong about imidacloprid, but were right about a pesticide causing the deaths of their hives.  Of interest is that fipronil takes a while to kill an insect that has consumed it, thus allowing ants, yellowjackets, and honey bees to take it back to the nest, where it eventually kills the entire colony — it’s actually a preferred bait treatment for those three insects.

Holder found that unlike imidacloprid, fipronil exhibits “time-reinforced toxicity,” meaning that its metabolites bioaccumulate in an insect’s body tissue, resulting in a lethal cumulative dose after a few days’ feeding.

Practical application: we beekeepers must demand that EPA require long-term feeding trials as a requisite for pesticide registrations.

Glyphosate in Your Groceries?

I’m not about to take an opinion on the recent concerns about glyphosate/Roundup® ― I’ll let our regulatory agencies review the evidence.  To date, none have been able to make a compelling case against the herbicide, which has transformed farming in the U.S., allowing growers to reduce erosion and improve soil structure by practicing “no till.”  And when I review the prevalence of Non-Hodgkin’s Lymphoma since glyphosate came on the market, I don’t see a huge spike.  Those applicators that claim that Roundup caused their disease, generally also admit to not following label instructions to wear protective clothing.  It’s unfortunate that the debate, instead of being conducted scientifically, is taking place in the courtroom, with attorneys and plaintiffs hoping for huge judgements in their favor.  That said, a recent study may explode both the science and the number of lawsuits:

Transgenerational effects of glyphosate?

A new paper in the journal Nature may, if it gets traction, shift the entire way that the chemical companies and EPA would need to assess any chemicals for allowed use.  Currently, registrants must submit data for short-term toxicity, and if indicated, for longer-term trials over perhaps multiple generations of test animals.  But these methods were arrived at before we understood transgenerational epigenetic inheritance, by which environmental exposure to temperature, diet, calamity, or any other stress or strong benefit can affect how the genes of the exposed individual’s children, grandchildren, or great-grandchildren may be expressed.

And that is exactly what Deepika Kubsad of Washington State University’s Michael Skinner lab, did with glyphosate [[7]].  Their results were stunning.  Smithsonian Magazine headlined its coverage with:

Biologist Michael Skinner has enraged the chemical community and shocked his peers with his breakthrough research.

The rest of the Smithsonian article is well worth reading [[8]].  What Skinner has shown is that a number of common chemicals can not only act as “endocrine disruptors,” but that exposed individuals can pass those effects on to their offspring without any change to their DNA, but rather by epigenetic (meaning “on the outside of genes”) changes that may be passed on  for generations.  This is called “transgenerational epigenetic inheritance.”  Skinner’s team found that the great-grandchildren of the rats exposed to glyphosate exhibited disease and pathologies associated with the exposure of their great-grandparents.

Before you jump to conclusions, be aware that the researchers had “exposed” pregnant female rats to extreme doses of glyphosate, which was injected under their skin, rather than consumed.  By my quick calculations, each pregnant female rat was injected with the amount of glyphosate equivalent to what a 140-lb pregnant human being would receive if injected with a full cup of the recommended dilution of Roundup to be sprayed upon weeds — and injected for six days in a row (to be clear, this is far more glyphosate than any human being, pregnant or otherwise, would ever be exposed to).

Despite the high dose of glyphosate (which did not appear to adversely affect the pregnant females): “There was no effect on litter size or sex ratio observed for any generation…”

But in subsequent generations there were some differences in weights and other abnormalities.

Thus, my worry level about glyphosate has not appreciably increased until we see this experiment replicated with more field realistic doses.  But that doesn’t mean that the study hasn’t gotten a lot of attention in principle.

The use of glyphosate and Roundup Ready® crops has revolutionized agriculture.  Glyphosate has been touted as one of the safest chemicals used in agriculture; but could it have insidious effects? [[9]]

Practical application: There’s a possibility that these findings may directly apply to honey bees, but more importantly, the chemical industry, chemical users in manufacturing, the ag industry, and the world’s regulatory agencies are in shock.  This study could disrupt the status quo, and signal a new beginning for how modern human societies — which have embraced the thousands of chemicals that we all use in everyday life — would need to test every new, and previously-registered, chemical for “safety.”  We can expect serious pushback and delaying tactics, but we may be entering a new age of chemical regulation.

Climate change and the “new Normal”

Speaking of new ages, we are now in the Anthropocene — the geological age in which Homo sapiens is the major cause of environmental and biological change on our planet.

One of those changes is in weather patterns (a.k.a. “climate”).  The Earth has been coming out of its current ice age for some tens of thousands of years (during which time human civilization developed).  But that change has accelerated in recent years, and many species on this planet are likely going to be unable to adjust.  Depending upon one’s politics, humans appear to be responsible for this rapid change, due to our unquenchable demand for the burning of fossil fuels.

One effect of the resulting higher CO₂ content of the atmosphere is warming, resulting in both droughts (as we suffered through for several years in California), or massive rainfall (due to greater evaporation of water into the atmosphere) — as many areas of the Midwest and East are enjoying this season.  Farming in the U.S. and much of the world may never again be the same.

I shot this photo of a field in Kansas this spring.  Note the center pivot irrigation system at the upper left.  Many acres of farmland will not be planted this season, due to excessive moisture.

A recent paper in Scientific American [[10]] helps to explain why we are seeing such extreme weather.  It appears that the warming of the poles affects how the jet stream moves the highs and lows that cause what we call “weather” from west to east across the continents.  The North Pole is warming more quickly than the lower latitudes, resulting in abnormally wide oscillations in the high- and low-pressure zones that used to progress across our continent.  These zones now often stall in place, leading to prolonged periods of drought or heavy rain.

Practical application: These extreme weather events are likely to be the “New Normal” [[11]].  They’ve made beekeeping far more difficult for us in California — our plant phenology is all screwed up, and in recent years we’ve either been parched or drowning in rain.  And this year, heavy rainfall is affecting agricultural areas across the country.  Independent of one’s political persuasion, there is a strong case to be made for invoking the Precautionary Principle — in this case, since we know that CO₂ traps heat in the atmosphere, perhaps it would be wise for us to stop throwing gasoline on the fire.

Wrap Up

The demands of the human population of our planet, coupled with our current chemical-heavy methods of agricultural production and urban life in general, along with our daily burning of incredible quantities of fossil fuels, are finally getting to the point that we will no longer be able to ignore the consequences.  Luckily, consumer and voter activism are starting to ignite in response, with the honey bee being a poster child for all pollinators and wildlife.  We beekeepers can perhaps help to shift the way we do things to a more sustainable manner, with less harm to man and the environment.

citations and notes

[1] Berheim, EH, et al (2019) Effects of neonicotinoid insecticides on physiology and reproductive characteristics of captive female and fawn white-tailed deer.  Scientific Reports 9: 4534.  Open access.

[2] Photo by Veledan – https://commons.wikimedia.org/w/index.php?curid=326306

[3] Mullin CA, et al (2010) High levels of miticides and agrochemicals in North American apiaries: Implications for honey bee health. PLoS ONE 5(3): e9754. doi:10.1371/journal.pone.0009754

[4] See Figure 16.3 in EEA (2013) Late Lessons from Early Warnings: Chapter 16 – Seed-dressing systemic insecticides and honeybees.  https://www.eea.europa.eu/publications/late-lessons-2/late-lessons-chapters/late-lessons-ii-chapter-16/at_download/file

[5] http://www.ipsnews.net/2004/03/environment-europe-alarm-sounds-on-bee-killing-pesticides/

[6] Holder, P, et al (2018) Fipronil pesticide as a suspect in historical mass mortalities of honey bees.  https://www.pnas.org/content/pnas/early/2018/11/26/1804934115.full.pdf

[7] Kubsad, D, et al (2019) Assessment of glyphosate induced epigenetic transgenerational inheritance of pathologies and sperm epimutations: Generational toxicology.  Scientific Reports 9: 6372. https://www.nature.com/articles/s41598-019-42860-0

[8] https://www.smithsonianmag.com/innovation/the-toxins-that-affected-your-great-grandparents-could-be-in-your-genes-180947644/ Just Google “skinner epigenetics.”

[9] Photo credit: By USFWS Mountain-Prairie. https://commons.wikimedia.org/w/index.php?curid=47582798

[10] Mann, M (2019) The Weather Amplifier. Scientific American, March.  http://www.meteo.psu.edu/holocene/public_html/Mann/articles/articles/MannSciAmFeb19.pdf

[11] Francis, J (2019) Rough Weather Ahead.  Scientific American 320(6): 46-53.