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Purdue university study confirms neonicotinoids on maize killing honeybees

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#1 ·
AMERICAN UNIVERSITY STUDY CONFIRMS NEONICOTINOIDS ON MAIZE KILLING HONEYBEES ON A VAST SCAL



The full text of this Purdue University Study can be downloaded (.pdf 120Kb) from the scientific journal 'Plus One' at this link
Multiple Routes of Pesticide Exposure for Honey Bees Living Near Agricultural Fields
http://www.moraybeedinosaurs.co.uk/neonicotinoid/routes%20of%20pesticide%20exposure%20for%20honey%20bees.pdf


Corn Seed Treatment As Lethal As It Gets For Honey Bees;
All Season Long, And Long After The Season Is Gone. It Just Keeps On Killing.


Alan Harman

Frightening new research shows honey bees are being exposed to deadly neonicotinoid insecticides and several other agricultural pesticides throughout their foraging period. The research, published in the scientific journal 'PLoS One' says extremely high levels of clothianidin and thiamethoxam were found in planter exhaust material produced during the planting of treated maize seed. The work, which could raise new questions about the long-term survival of the honey bee, was conducted by Christian H. Krupke of the Department of Entomology at Purdue University, Brian D. Eitzer of the Department of Analytical Chemistry at the Connecticut Agricultural Experiment Station and Krispn Given of Purdue.

Neonicotinoids were found in the soil of each field we sampled, including unplanted fields, they report. Dandelions visited by foraging bees growing near these fields were found to contain neonicotinoids as well. “This indicates deposition of neonicotinoids on the flowers, uptake by the root system, or both,” the report says. “Dead bees collected near hive entrances during the spring sampling period were found to contain clothianidin as well.”

The researchers also detected the insecticide clothianidin in pollen collected by bees and stored in the hive. “When maize plants in our field reached anthesis, maize pollen from treated seed was found to contain clothianidin and other pesticides; and honey bees in our study readily collected maize pollen. “These results have implications for a wide range of large-scale annual cropping systems that utilize neonicotinoid seed treatments,” the report says. The research was funded by grants from the North American Pollinator Protection Campaign and the Managed Pollinator Coordinated Agricultural Project.

There have been red flags about pesticide exposure for some time and of the many compounds detected, the neo-nicotinoid group has received the most attention. As a group, neonicotinoids possess several key attributes that have seen their heavy adoption in both agricultural and urban environments, including low vertebrate toxicity and the ability to be translocated by plants.

Neonicotinoids are also persistent, offering the potential for a large window of activity. The new report says the half-lives of these compounds in aerobic soil conditions can vary widely, but are best measured in months – 148 - 1,155 days for clothianidin.

Among the largest single uses of these compounds is application to maize seed. Production of maize for food, feed and ethanol production represents the largest single use of arable land in North America, reaching a record 35.7 million hectares (88,216,620 acres) in 2010 and is expected to increase. All of the maize seed planted in North America except for 0.2% used in organic production is coated with neonicotinoid insecticides.

Two major compounds are used – clothianidin and thiamethoxam, with the latter metabolized to clothianidin in the insect. The application rates for these compounds range from 0.25 to 1.25 mg/kernel. These compounds are highly toxic to honey bees – a single kernel contains several orders of magnitude of active ingredient more than the published LD50 values for honey bees – defined as the amount of material that will kill 50% of exposed individuals, which ranges from 22–44 ng/bee for clothianidin (contact toxicity).

In fact, the amount of clothianidin on a single maize seed at the rate of 0.5 mg/kernel contains enough active ingredient to kill more than 80,000 honey bees.

Maize seeds are typically planted at a rate of about 12,500 kernels/hectare (30,875 kernels/acre). The latest research was begun after reports of bee kills at Indiana apiaries in the spring of 2010 that coincided with the peak period of maize planting in the area. Analyses of these bees and pollen from the hives revealed that both clothianidin and thiamethoxam were present on dead bees and in pollen collected from a single hive. The compounds were also present in dead bees from other hives but not in bees from hives that did not show mortality. Also found was atrazine, a herbicide that is commonly used in maize production and is relatively non-toxic to honey bees.

The results prompted researchers to carry out more experiments to determine how honey bees may be gaining exposure to clothianidin and other pesticides commonly applied to either maize seed or to plants later in the season. They collected samples from a variety of potential exposure routes near agricultural fields and analyzed them to determine whether pesticides were present. They sampled soils, pollen both collected by honey bees and directly from plants, dandelion flowers, and dead and healthy bees. They even checked waste products produced during the planting of treated seed. Maize seed is sewn with tractor-drawn planters that use a forced air/vacuum system and a perforated disc to pick up individual seeds and drop them into the planting furrow at the selected spacing. Maize kernels treated with neonicotinoids and other compounds such as fungicides do not flow readily and may stick to one another, causing uneven plant spacing. To overcome this, talc (a mineral composed of hydrated magnesium silicate) is added to seed boxes to reduce friction and stickiness and ensure the smooth flow of seed. Much of the talc is exhausted during planting, either down with the seed or behind the planter and into the air using an exhaust fan. Researchers sampled the waste talc after planting to determine whether this material was contaminated with pesticides abraded from treated seeds. The waste is a mixture of the talc that has been in contact with treated maize kernels and minute pieces of the seeds.

“Soil collected from areas near our test site revealed that neonicotinoid insecticide residues were present in all samples tested, with clothianidin occurring in each field sampled,” the research report says. “Herbicide residues were also found in these samples.”

Extremely high concentrations of clothianidin were found in talc exposed to treated seed along with fungicides applied to the seed. Analysis of talc used to plant untreated seed found low quantities of the same pesticides, likely due to contamination and reflecting the difficulties associated with thorough cleaning of equipment between plantings. Direct sampling of anthers revealed that many of the same compounds were present in maize grown from treated seed, but in far lower concentrations. Collection of pollen from traps in the field showed thiamethoxam was present in three of 20 samples, while pollen containing clothianidin was present in 10 of 20 samples. Fungicides were also frequently detected: azoxystrobin and propiconazole were found in all pollen samples, while trifloxystrobin was found in 12 of the 20 samples. Maize pollen is frequently collected b y foraging honey bees while it was available and maize pollen made up more than 50% of the pollen collected by bees in 10 of 20 samples. Samples collected again last year revealed some similar trends.

“Clothianidin was found on all the dead and dying bees we sampled, while the apparently healthy bees we sampled from the same locations did not contain detectable levels of clothianidin,” the report says. “Atrazine and metolachlor were also found, providing further evidence that these bees were foraging near agricultural fields; as these herbicides are commonly applied prior to or during maize planting.

When sampled, the contents of wax combs removed from two hives at the same apiary, researchers found both clothianidin and thiamethoxam in pollen removed from both hives. Nectar did not contain either compound. The miticide coumaphos was found at low levels in each nectar and pollen sample as well.

Both soil and dandelion flowers obtained from the fields closest to the affected apiary contained clothianidin and this could have resulted from translocation from the soil to the flower, from surface contamination of the flowers from dust, or a combination of these two mechanisms. Dandelion flowers growing far from agricultural areas served as controls and no neonicotinoids were detected.

“These results demonstrate that honey bees living and foraging near agricultural fields are exposed to neonicotinoids and other pesticides through multiple mechanisms throughout the spring and summer. The potential for greatest exposure (and the period when mortality was noted), occurs during planting time when there is potential for exposure to extremely high concentrations of neonicotinoids in waste talc that is exhausted to the environment during and after planting. Furthermore, we show that bees living in these environments will forage for maize pollen and transport pollen containing neonicotinoids to the hive. Pollen contaminated with levels of neonicotinoids similar to those shown in our results has been known to impair pollinator health,” researchers said.

The levels of clothianidin in bee-collected pollen the researchers found were about 10-fold higher than reported from experiments conducted in canola grown from clothianidin-treated seed. “Detection of clothianidin in pollen, both in stored pollen in cells and in pollen traps is a critical finding because clothianidin is even more toxic when administered to bees orally, with an LD50 of 2.8–3.7 ng/bee,” the report says. “Given an average weight of 80–100 mg/bee, some of our pollen sample concentrations exceed the oral LD50. This, combined with the result that our samples of dead and dying honey bees consistently demonstrated the presence of clothianidin, suggests that the levels of both clothianidin and thiamethoxam found in our sampling of stored pollen in May of 2011 may have contributed to the deaths of the bees we analyzed.”

The results also showed clothianidin present in the surface soil of fields long after treated seed has been planted. “All soil samples we collected contained clothianidin, even in cases where no treated seed had been planted for two growing seasons,” the report says.

During the spring planting period, dust that arises from this soil may land on flowers frequented by bees, or possibly on the insects themselves. Of potentially greater concern are the very high levels of neonicotinoids and fungicides found in the talc that has been exposed to treated seed. “The large areas being planted with neonicotinoid treated seeds, combined with the high persistence of these materials and the mobility of disturbed soil and talc dust, carry potential for effects over an area that may exceed the boundaries of the production fields themselves.”

“A key mechanism for honey bee exposure may occur during the period when maize is typically planted across much of the Midwest (mid-April through early May). At this time, the energetic requirements of honey bee colonies are increasing rapidly and pollen and nectar resources are being gathered for colony growth. Talc and soil dusts from planting are mobile and have the potential to contaminate any flowering plants that are commonly found in or near agricultural fields and are visited by honey bees, including dandelion. It is a preferred pollen and nectar source for honey bees during this period, when floral resources are relatively limited.”

Later in the season, when planting is largely complete, the researchers found bees collect maize pollen that contains translocated neonicotinoids and other pesticides from seed. Translocation of neonicotinoids into pollen has previously been reported for maize grown from imidacloprid-treated seed, but the researchers say the degree to which honey bees in their study gathered maize pollen was surprising. “The finding that bee-collected pollen contained neonicotinoids is of particular concern because of the risks to newly-emerged nurse bees, which must feed upon pollen reserves in the hive immediately following emergence,” they say.

“Lethal levels of insecticides in pollen are an obvious concern, but sub-lethal levels are also worthy of study as even slight behavioral effects may impact how affected bees carry out important tasks such as brood rearing, orientation and communication.” Also potentially important are the three fungicides found in bee-collected pollen samples – trifloxystrobin and azoxystrobin and propiconazole. Azoxystrobin and trifloxystrobin are frequently used in maize seed treatments as protectants and all three are widely applied to maize in North America, even in the absence of disease symptoms. These findings have implications both for honey bees located near these crops year-round, but also for migratory colonies such as almonds and other fruit and nut crops, the report says.
 
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#3 ·
In the spring of 2010, many of the Purdue bees were killed (along with the bees of many other Northern Indiana beekeepers) during a time of heavy corn planting. It had been a very dry spring, and there was a lot of dust created by the pesticide-coated corn seed as it was jostled about in the planting hoppers. Dr. Greg Hunt and his staff have been working on this research since then. Glad to see that it's finally been published.
 
#5 ·
My reading on this study is that it dosent really break any new ground (pardon the pun). It is not news that these neonics are highly toxic to bees that are directly exposed to it. If hives are near dusty planting conditions especially when foraging is taking place in those fields bee losses will most definitely result. With the no-till that is so commonly done it is not that unusual to have some stand of weeds that the bees may be working that is being planted through. Most often these fields are "black" but certainly not always. This is all very condition specific and something that could be addressed with a local farmer ahead of the planting season. To make the leap from this to assuming that any pollen gathered later in the summer is an equally significant problem that is either a cause or contributing factor to overall hive health is where significant disagreement has taken place among researchers. In our area we have seen a considerable increase in corn and bean acreages in the past two years yet the overall condition of our bees has improved during the same time frame. It is important to note, though, that all of our bees are moved in after virtually all the spring planting has been done.
 
#7 ·
Jim -

Thanks for giving your input on this, which I value. Since my bees are sitting there year round, I'll be watching this spring to see if I see any possible impact. I'll also observe what the routine is with the local farmers.
 
#16 ·
most of my hives are very close to cow corn fields, most of the farmers don't use no-till, none of the farmers are aware that there are neonics on the seeds from what I can tell. all of the fields have weeds close to them but they till under the fields, I haven't had any problems that I can attribute to the corn, one thing to remember though, this is a very wet area so usually dust is at a minimum. I'm more worried about when they follow the corn with alfalfa, since the neonics stay in the soil for years I really hope they get it cut b/4 it blooms.
My partner did have a bee kill at the same time they were planting around him, once in the last 4 years, we weren't aware of the seed's being treated or else would have sent away some dead bees for testing. I monitor my honey harvest closely and have not seen any decrease since they planted the corn two years ago, but they are plowing in all my golden rod at a terrible pace.:eek:
 
#8 ·
Both soil and dandelion flowers obtained from the fields closest to the affected apiary contained clothianidin and this could have resulted from translocation from the soil to the flower, from surface contamination of the flowers from dust, or a combination of these two mechanisms. Dandelion flowers growing far from agricultural areas served as controls and no neonicotinoids were detected.
I think you are back-dooring this point. It is not just the planting time that the nectar and pollen is toxic and toxicity increases with time (use).
 
#9 ·
Great shock and consternation to discover (gasp!) that chlorinated hydrocarbons accumulate in the environment, eh?

Obviously the current crop of mad chemists at the agrobusiness firms haven't read any of the environmental research from the last 50 years, since they advocate dumping hundreds of millions of tons of very highly toxic very persistent materials into the soil.

The major problem here is that no one seems to have tested for the persistence of neo-nics in soil. It was assumed they would wash out and degrade very rapidly and never accumulate. Why anyone thought that I don't know, as there is more than ample literature concerning the persistence and bioaccumulation of any number of other chlorinated substances (DDT, Toxaphene, Heptaclor, etc) going back 60 or 70 years now, all equally supposed to "deteriorate" rapidly in the environment. They do, actually, degrade fairly rapidly when exposed to sunlight and the UV in it, but UV only penetrates a few thousandths of an inch into soil for some reason.

EPA and USDA more or less grandfathered these chemicals into use, assuming they were very similar to the realted pyrethrins, which do NOT accumulate or persist (and I assume they were told this by Bayer, et al.). Nope, they hang around for months if not years, so treated seed, much of which is probably seriously overtreated in good old agribusiness style, leads to higher and higher amounts of neo-nics in the soil, hence in the plants, hence in the pollen, nectar, and guttation exudates -- these are probably the worst thing for bees, as bees will greedily pick up the high sugar guttation droplets from small corn seedlings, where the neo-nics will be in the highest concentrations (very small plants, after all, lots of cool, damp nights in the early spring, lots of guttation).

The other area not investigated at all was the low level, non-lethal exposure effects of neo-nics. Most likely this will result in the same sorts of things mites cause -- lower brood success, shorter lived, lower weight bees, and general lack of vigor. Same as anything else that impacts general health.

Mix all of this in with the gross overspraying of glyphosates on "RoundUp Ready" crops and you will have serious lack of forage to add to the problems bees have. In my area, there are very few roadside plants left, just roundup resistant grasses, since the farmers spray very sloppily. No blackberries, no wildflowers, nothing. In many cases, severe erosion from lack of plant life on the sides of the huge drainage ditches.

I flew home from Chicago in early June this year at fairly low altitude, and was rather shocked at the lack of anything green. Corn was planted (late, due to very wet weather) and not showing yet, and so the ground was brown for dozens of miles in all directions. Nothing green along the roadways since the feilds extend right up to the pavement, obvious severe erosion in feilds, just brown soil and pavement, releived once in a long while by a flat, mowed short lawn. The only woodlands were where it was impossible to plow.

Hardly a surprise beekeeping is in decline -- they have to eat, after all, and these days in "farmland" there is nothing for bees to collect the vast majority of the year. They will collect huge amounts of corn pollen, mainly because there isn't any other pollen for them out there. It's not the best for them, doesn't have the correct amino acids, but it's all they have. Since there are VERY few farms raising livestock, there is no clover or anthing like that, just the weeds in the fields before they are drenched in RoundUp.

Peter
 
#17 ·
I flew home from Chicago in early June this year at fairly low altitude, and was rather shocked at the lack of anything green. Corn was planted (late, due to very wet weather) and not showing yet, and so the ground was brown for dozens of miles in all directions. Nothing green along the roadways since the feilds extend right up to the pavement, obvious severe erosion in feilds, just brown soil and pavement, releived once in a long while by a flat, mowed short lawn. The only woodlands were where it was impossible to plow.
You must be referring to central Illinois, where my family is from. Northern and southern Illinois is not like that. Around here there are lots of ditch weeds and stands of trees and brush between fields.
 
#10 ·
So what does this report mean to us? I am surrounded by corn fields, cow corn mostly for silage. Will this report get other universities looking in this direction, I would hope they have been anyway
after the ban in Europe. Does this mean we will see a ban in Neo-cides here? I could move my bees out of here during planting season, that may help but its not a fix. The U.S. gov may do something about it in 2020 but what do we do until then?
 
#12 ·
So if I'm a big Ag Chem company and start feeling pressure from USDA about my chemicals (how likely is that?), then I lobby to have the treated corn, etc. labeled as strictly an energy/ethanol fuel (not fit for human/animal consumption) & transfer its control to the Department of Energy as vital to national security.

I doubt that I am the originator of this thought.
 
#14 · (Edited)
Unless they can make clothianidin or thiamethoxam taste and appear as one or more of the following:

Salt, Pepper, Butter, Honey, Molasses, Sugar, Milk, Cream, Cheese, Numerous Type of Gravy (Sausage, Red-Eye, Bacon/Drippins, Flour...)

And doesn't kill/disable any of the following (in general order of importance):

Pick-up, Dogs, Pigs, Cows, Chickens, Fish, Bees, Wild Turkey, Children, Us, Racoons, Possums, Our Cousin-in-Law Spouses, our Neighbors Spouses, Our Spouses

Here in the South, we would prefer our grits not messed with - and what about my moonshine reputation?
 
#15 ·
This is a very serious issue, as probably 90% of beehives are withing flying range of a cornfield, at least in the easter half of the US.

The real problem is indiscriminant use of pesticides with no evaluation of effects beyond the immediate application to crops.

Most pest can be controlled by changing the way we grow crops, but those alternate methods are not conducive to massive corperate agribuisness. I dont' see that as a problem, but the people getting rich soaking us with chemicals do.

Certainly the problems neo-nics cause with bees is another argument to ban them, on top of the other issues no one wants to talk about (like aquatic toxicity -- anyone in favor of no fish in the rivers, streams, and lakes?).

Peter
 
#18 ·
So we are applying chemicals with half lives of years. So if we should decide that this is a mistake the fields might have to be left fallow for a century or so until one could say that they are essentially gone. These chemicals are taken up by the plants so that the plant becomes poisonous to the target insect. Poisonous enough that (I hear) ear worms that attempt to burrow into the ears are killed. And poison which remains in the plant at harvest. And then I get to eat it. Milk cows get to eat it and (pure conjecture here) concentrate the poison in their milk. And I drink it. If we find out that there is some slow to show bad effect (say birth defects or cancer...) then what to do, essentially all the farm land in this country now contains this stuff. All on the assurance of agribusiness and agrigovernment that all is well, don't worry. Meanwhile we hear of increasing autism, food allergy, asthma and who knows what all. None of which can be explained. So far we don't even know the chronic toxic effects on bees, which are much more sensitive and have a much shorter life cycle. Good luck to us all.
Bill
 
#20 ·
Meanwhile we hear of increasing autism, food allergy, asthma and who knows what all. None of which can be explained.
Ah, Bill it can be explained but even cutting off the financial benefits of medical solutions is hard to give up when you are on the receiving end. Do you really think it would take a 100 years to solve the cure for most cancers when it only took 10 years to land on the moon when the Russians wanted to do it?
 
#23 ·
I do think it is important to keep perspective on this issue. I know what pesticide poisoning does to bee hives, I have seen it many times in years past with foliar spraying. Neonics have lessened the need for foliar spraying. Since corn is the largest crop in the US and I would assume the majority of hives are within flying distance of a corn field it seems that the easily observed effects of pesticide poisoning should be quite apparent if direct contact kill was a problem. As far as any residue in the fields it would be nice to see some hard data on that as far as how common it might be and what the concentrations are as this report (as near as I can tell) is only dealing with a specific case. The real issue on neonics has always been the potential of sub lethal dosages and if that could be more of a stealth killer. The majority of the testing up to this point has failed to show a connection to the original ccd type symptoms but instead has suggested that viruses is probably a much more plausible culprit. That is not to say that neonics arent perhaps a contributing factor. In any case let's work off what we know and any documented losses that can be proven.
Here are my unscientific observations, we have bees on over 100 locations all within flying distance of corn fields. Figuring a 2 mile flight radius they would cover well over 1000 square miles and I haven't yet seen anything that concerns me. I think that is a pretty significant piece of evidence.
 
#25 ·
I don't like biased studies, and this study is biased. I don't like fear mongering and that is a lot of what I am reading in this thread. I also don't like pesticides in all their various flavors.

This study is biased because of who paid for it and the innuendo that is included in lieu of hard facts. The association of bees dead with small amounts of neonics in them does not prove that the neonics killed the bees. They are going to have to back up this observation with cold hard provable facts.

The statements made so far in this thread sound like someone is holding a smoking gun. This gun is not smoking folks. Read the article with a bit less bias and see what it is really getting down to.

The significant issue found in this study is the proliferation of dust from the seed during planting. There is a reasonable establishment of cause and effect that bees are dying during corn planting and that they are dying from neonic exposure. This means the seed companies are going to make a huge effort to coat the seed with a second layer of inert material to reduce the dust problem.

The buildup of neonics in soil was pretty much limited to 3 years. What they didn't say is what happens in a dry region where rainfall is less than 20 inches per year. It would be reasonable to guess they would persist longer under such conditions. There is also reason to suspect that the residue buildup will be incorporated into corn plants and into corn pollen since these chemicals have definite systemic activity. What is not established is whether or not the bees are getting a lethal dose from the pollen.

The Bayer studies that led to licensing of these chemicals was seriously flawed. It did not take into account interactions between bees and corn when the area of distribution is as large as it is in the real world.

My take on this is that it is one more sign of a serious problem with a relatively new pesticide. We need more studies.
 
#26 ·
I read the study and the most interesting new piece of information was the used talc exhausted out of the air planter. This appears to be the significant, new, potential exposure to honey bees. Although, at this point there is no evidence of how they are being exposed. It could be they would forage this material if it were found in concentrated areas. I haven't worked with these planters so I'm not sure how the exhausted material will accumulate. This will be something for me to find out this spring!

When reading the tables at first I was a little confused since I couldn't understand how foraging bees could bring in corn pollen during planting time. While reading the study I learned that the plots for the study were not planted until July. This is concerning since this is not "typical" planting time and does not represent what colonies in mid-western agricultural areas will face during a typical planting season.

Also, if dead bees were tested for clothiandin levels in July what is the source of the clothiandin? Pollen from surrounding corn fields? Dandelion, July is well past peak flowering. Exhausted planter talc? The authors noted it was not clear how bees would be exposed to high levels of clothiandin after the seed was planted.

As far as soil pesticide levels. I found it interesting that clothiandin levels were essentially the same in the unplanted soil as the production fields surrounding the test plots. This data is starting to develop a baseline. It would be interesting if the authors continued to collect this data to see what soil levels do.

Another interesting point made was that pollen had sub-acutely toxic levels of clothiandin. It was estimated it would several days of consuming the pollen to reach the LD50 level and metabolic activity would decrease residual levels. The impact of sub-acute levels of exposure needs to be studied. It would also have been nice to check clothiandin levels in capped brood to see how much is making it into the bees.

I was surprised no clothiandin was found in nectar. It has been found in guttation from corn seedlings. It is found in pollen. I don't know if it isn't in nectar or the levels are below detection.

Something to note, all levels of pesticides are reported in parts per billion. It wasn't that long ago that those levels were almost undetectable.

I was surprised there was no discussion about the detection of coumaphos. What was the potential source? Was it actually applied to the hives for mite control?

The study is a first step to answering some questions about how, or if, neonics impact honey bee colonies. I hope the authors continue to pursue this research and provide some hard answers to the questions we all have.

Tom
 
#27 ·
Jim Lyon wrote:

Figuring a 2 mile flight radius they would cover well over 1000 square miles and I haven't yet seen anything that concerns me. I think that is a pretty significant piece of evidence.

I agree. Keep up the keen observations please.

Crazy Roland
 
#29 ·
Here is a link more easily downloaded than the one provided by borderbeeman. http://www.plosone.org/article/info:doi/10.1371/journal.pone.0029268
As you may notice it allows you to cut, copy, and paste so you can more easily make a side by side comparison between the un-quoted material in the beginning post and the information published by those who authored the final paper.

I found it somewhat unusual that despite all the previous claims to the contrary NO traces of clothianidin and thiamethoxam were detected in any of the nectar tested, despite numerous previous claims that these chemicals readly translocate to nectar and corn seedling guttation droplets. But for the sake of honesty I admit that there is this little thing about corn not producing nectar.

I call you attention to table 4. http://www.plosone.org/article/slid...RI=info:doi/10.1371/journal.pone.0029268.t004
One of the two hives situated at a TREATED corn field showed LOWER concentrations of clothianidin after planting than before clothianidin treated seeds were planted. Why? One of the 2 hives situated at an UNTREATED corn field showed HIGHER concentrations of clothianidin after planting untreated corn seeds than before untreated seeds were planted. Why?

Because no base line information was available for 2010 or earlier. I can only assume that table 4 means the clothianidin and thiamethoxam contamination of pollen occurred during the dry and dusty planting conditions encountered in 2010 and not during 2011. In a previous thread I already discussed the late and damp 2011 planting season in the American Mid-West. The good news is that this study dove tails perfectly with the brief suspension of clothianidin and thiamethoxam use in Europe following a similar corn planting accident.
 
#30 ·
Or it could indicate contamination from a source farther away. Mary Anne Frazier, and others, have shown that bees forage a lot farther away from the hive than previously thought, covering a lot more acreage. Is it possible that the contamination came from another source, farther away?
 
#31 ·
All wax from hives treated with coumaphos contain fairly large amounts of it, since it dissolves in the wax. This includes "new" foundation, which is made from recycled wax. Probably a good way to breed resistant mites, along with low level toxicity to bees (and possible cause for absconding -- too much nasty stuff in the comb).

Bees metabolize neo-nics quite rapidly, and excrete them fairly quickly as well, so I'm not surprised at low levels in live bees. Usually they die very quickly at lethal levels, and non-lethal levels vanish over a few hours as the bees excrete them. The question is what does low levels of neo-nics do to bees? They are central nervous system poisons, after all -- what does something like this do to the developing brood? Change behaviors? Make them nice homes for phorid flies?

Lots of questions, not very many answers, and remember, neo-nics are not used in trace amounts. At a few mg per seed, the dosage on a field is in the dozens to hundreds of pounds range, and if they do persist in the soil, the amount starts to get really high.

Another question is what are we doing to the ecology of the field when we poison EVERY insect out there.

All of this should have been answered BEFORE neo-nics were approved for field use, whatever the crop. Neo-nics are a huge problem in Europe, and there is considerable pressure to have them banned completely.

Peter
 
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