New Sulfoxaflor Insecticide Harms Bees

o-DEAD-900Minneapolis, September 15 Several months ago, the European Union banned the three major neonicotinoid (neonic) insecticides, following years of accumulating and convincing evidence that they harm bees and other organisms.

Global research with a European emphasis  and research focused on the U.S. meanwhile show that neonics rarely benefit crops in their most prevalent application as seed coatings.

Regardless of the science, the pesticide industry will undoubtedly try to reinstate neonicotinoids, and prevent restrictions in the U.S. It will also try to substitute other insecticides for the same purposes and try to convince farmers and regulators that they are needed and safe.

New research that one of the leading candidates for replacing neonics, called sulfoxaflor, could be similarly harmful to bees shows that switching to alternative insecticides is not a solution for the environment. It is yet more evidence that we need a new way of thinking about pests, and farming generally, based on agroecology.

Sulfoxaflor’s effects

It should be kept in mind that the neonicotinoids themselves were considered generally safe when first introduced. Given the failings of the regulatory agencies to ascertain their risks, which allowed neonics to become the most widely used insecticides on the planet, it is especially important to understand the potential risks from insecticides that might replace them.

The new research found that, as with neonics, extremely small quantities of sulfoxaflor is toxic to bees. And, also like neonics, it can affect reproduction and other aspects of bee life that are not immediately apparent, but nonetheless harm bee populations over time.

These types of effects are often as or more important than immediate mortality, but more insidious in that they are often not as obvious or detectable in the short term.

For example, the new research shows that reproduction of sexual bumblebees was reduced by 54% after exposure to realistic levels of sulfoxaflor sprayed onto plants. Exposure was 5 parts per billion (PPB) for two weeks after spraying. This is also not an uncommon level of residues seen previously from seed treatments with neonics.

The ability to use sulfoxaflor as a seed treatment is in fact one of the most important attributes that it shares with neonics. It is highly soluble in water, which allows it to be absorbed and circulated throughout the plant, a property called systemic. By circulating through the plant, it ends up in pollen and nectar that pollinators and other helpful insects feed on, as well as leaves and stems. This is a property that many current insecticides do not possess.

And it is extremely toxic to insects, so that very small amounts, even compared to many other common insecticides, can kill pests, but also myriad helpful insects like pollinators.

It is also likely that this will make sulfoxaflor toxic to other insects and related organisms (invertebrates) that control insect pests, recycle organic matter in the soil and elsewhere, serve as food, and perform other important functions. And because it is very water soluble, it is likely to readily enter streams and harm aquatic insects that are the foundation of food webs in aquatic ecosystems.

Only about 5 percent of neonicotinoids are taken up by the seed, while the rest ends up in the soil and the wider environment. I have not seen similar data on sulfoxaflor, but its biochemical properties suggest that it will act similarly.

Most older insecticides are not systemic. Some that are systemic are not acutely toxic enough to be effective at low concentrations when dispersed throughout the plant.

The tests required by regulatory agencies for environmental safety of pesticides have not reliably identified long-term types of harm, such as lower reproductive potential or reduced foraging ability of bees. For example, while the EU has banned three major neonicotinoids, it approved the use of sulfoxaflor in 2014.

Hence, the importance of the kinds of independent research that the new paper provides.

Sulfoxaflor isn’t the only threat

There are a number of other newer insecticides, developed over the past 10 or 15 years and just recently entering commercialization, that are also systemic, and might replace neonicotinoids for many of their functions, including as seed treatments.

Several have been described as narrow spectrum, suggesting that that are safer than previous insecticides. But what this means in practice is often just that they seem less harmful to humans or some classes of organisms based on industry data submissions to EPA, while still being extremely toxic to many types of insects or other organisms.

Some of these insecticides have actually been designated “reduced risk” by U.S. EPA, but again, that designation has a limited meaning. It designates pesticides that are purportedly somewhat less risky in some ways than older pesticides used for the same purposes under EPA testing requirements. It does not necessarily mean that they have no or little risk. And when it comes to the population level risks I have described above, they may be as or more risky than previous insecticides.

In fact, as I recently wrote, there is already evidence that some of these insecticides may be harmful to important beneficial insects such as those that protect our crops.

Because they are new, there is considerably less research on these insecticides than for neonics or older chemicals. But the early evidence that they can harm beneficial insects should be taken as a warning.

This is especially true given the past failures of the regulatory agencies to identify longer-term environmental impacts. It is also true because of the tradeoff between efficacy and safety, which I described in the article linked above.

In practice, it is very challenging to produce an insecticide that is effective against enough different insect pests to provide profits desired by pesticide corporations, but at the same time is safe for beneficial insects that share similar genes and metabolism with pest insects.

Agroecology, a new paradigm

The dilemma of the tradeoffs between efficacy and safety, along with the fundamental motivation of profit from pesticides, leads to ever newer generations of insecticides. This also leads to claims of safety, at least when “used according to the pesticide label” (the mantra of the pesticide industry and EPA).

This in turn is justified by the ag chemical industry and its supporters, such as the Farm Bureau and large commodity crop grower organizations like the National Corn Growers Association, by the supposed need for largely unimpeded use of pesticides to support high levels of production.

But this is simply factually and scientifically wrong.

Following the science of agroecology greatly reduces or eliminates the need for synthetic pesticides while maintaining or increasing productivity. Long-term research shows that for Midwestern crop rotations  the succession of crops from year to year in the same field that include more than corn and soybeans have higher yield than commercial corn-soybean rotations.

They are also much better for water quality, soil health, and biodiversity, while greatly reducing pesticide use. Other research shows similar results in Europe. Another study shows that yields are higher than industrial agriculture in droughts or excessive precipitation, which are likely to become more common in many regions with climate change.

But as with climate change, where the entrenched and politically powerful fossil fuel industry tries to delay or prevent the changes needed to prevent climate catastrophe and has undue influence over politicians, the industrial agriculture industry stands in the way of vitally needed changes in farming.

The reasons for this go way beyond mere matters of farming methods, into areas of social justice, intersectionality, federal farm and food policy, and international agriculture trade.  I hope to address some of these issues in future posts here.

Will Minnesota restrict neonicotinoids?

The clash over insecticides reverberates here in the Upper Midwest.

One of the important issues being considered by Minnesota governor Mark Dayton’s Committee on Pollinator Protection is the use of neonicotinoid insecticides (see nearby USGS/ARERC maps for one corn-soybean neonicotinoid, thiamethoxam). The committee posted a draft report dated August 3, replete with recommendations. The committee will be working on finalizing this report over the next few months.

Map Thiamethoxam U.S. Use 2000-2014The draft currently mostly favors voluntary measures, education, and incentives to reduce pesticide use, as well as provisions to increase badly needed pollinator habitat. But it also contains several reasonable restrictions on the use of neonics, such as eliminating the use of soybean seed treatments.

One opportunity missed in the draft is the lack of any mention of the value of agroecology.

Instead, the adoption of integrated pest management (IPM) is incentivized. IPM is often favored by entomologists, whose focus is understandably on pest management, rather than the ecological health of the entire ecosystem. Although it can include aspects of ecological farm management, in practice it often defaults to merely monitoring pests and foregoing insecticide use unless economically-damaging levels are reached.

Agroecology puts primary focus on growing food in ways that reduce pest levels, but also closes nutrient cycles which limits water pollution, improves soil fertility, reduces climate change emissions, and increases all kinds of biological diversity.

The current draft includes an indemnity plan that could encourage risk-averse farmers to forego use of neonic seed treatments. Under this provision, farmers who do forego would be insured in the unusual event of damaging pests that may have been otherwise controlled by neonics.

Farmers currently may use these insecticides as a form of “cheap insurance” even if they are not convinced that they are needed. However, several research entomologists have disputed that thinking, given how rarely neonics prevent yield loss. Actual insurance against such rare losses would be better for everyone, because from an actuarial perspective, this should mean low cost. And in fact, a European study showed that the cost of such insurance would be much less than the cost of the insecticides.

That is why the Pollinator Committee has the potential for a win-win in supporting the elimination of neonic seed treatments and other uses. It should have done so for corn as well as soybeans, but the current draft would still be an important step forward if approved.

But the committee should also consider, or at least alert and advise the governor, on the risk in replacing neonics with other insecticides such as sulfoxaflor. It is difficult to preemptively consider all other insecticides that may be later approved by EPA, which is why there needs to be a standing advisory body on these issues, made up of independent citizen stakeholders.

The very infrequent benefit from neonics, and the existence of non-insecticide alternatives to seed treatments, are ample reasons why harmful alternatives, including sulfoxaflor, should not be allowed as substitutes for neonics.

doug_gurian-shermanDoug Gurian-Sherman, Ph.D., is a research consultant with Strategic Expansion and Trainings, LLC, Minneapolis, focused on supporting ecologically based sustainable agriculture, food sovereignty, and food equity. He was previously a scientist at the U.S. Environmental Protection Agency (EPA) and advised the National Research Council.

The ideas and opinions posted here are the author’s and not necessarily that of ARERC as an organization.





Creative Commons LicenseThis work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

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