Canola’s flea beetles – enjoying a taste of heaven
I am still trying to understand why neonic-otinoids have not been a problem in western Canada. 40% of all seeded crops in Manitoba, Saskatchewan, and Alberta are canola. And 100% of the seed is treated with neonics. So, at least 40% of western Canada’s cropland is treated with neonicotinoids every year. (I say “at least” because some of the other crops out here are also treated.) I just attended a meeting in which guest speaker Greg Sekulic, a canola growers’ agronomist, spoke about the importance of bees to the canola growers. Greg spoke about the relationship of canola and bees, which can be boiled down to this: Canola needs bees; bees need canola. What’s good for bees is good for canola. Simple enough. Canola seed is vastly more plentiful if healthy bee populations are around to pollinate it.
Unfortunately, commercial plots of canola can not survive without pesticides. This monocultured oil seed is heaven on earth for the little flea beetles, which seem to imagine that the gods planted all those yellow flowers just for them. In the past, farmers ran across their fields with spray booms – or hired airplanes – to kill the nasty pest. I know, because beekeepers used to lose hives when foliar sprays were used exclusively in the old days. Beekeepers who have never stared in horror in a bee yard as spray planes pass overhead don’t understand this. It would be tragic to go back to the old ways and the old chemicals. I wish farmers would grow canola without pesticides, but I don’t think that will happen in my lifetime. Canola, related to cabbage, is affected by cabbage worms, cabbage root maggots, cabbage pod weevils, aphids, thrips, cutworms, blister beetles, grasshoppers and locusts, lygus bugs, flea beetles and their cousins the striped flea beetles. Poisons will be part of the farming business for a long time.
So we have the odd situation that a hugely important mid-summer nectar source for honey bees has been treated – 100% – with neonicotinoids for years, yet bees are not suffering. Before the hate mail starts again, let me remind you that I know neonicotinoids are poisons and I have written about this many times in the past. One tragic case of neonics sprayed on blossoming orange trees in Florida killed millions of bees and cost beekeepers hundreds of thousands of dollars. (The offending party had not followed label instructions which clearly state no spraying during blooming. The state of Florida slapped a couple of tiny little $1,500 fines on the bad guys who killed the bees – which turned out to be a huge multi-million-dollar conglomerate. You should read the whole story.)
Last winter Ontario beekeepers suffered horrific losses – almost 60% of the hives put into winter died. Some are blaming neonics used on corn seed. Maybe they are right. But southern Alberta beekeepers with their hundred thousand hives sitting in nico-treated canola fields lost only 15% of their colonies. Figuring out this paradox should make a fascinating – and important – research project.
Bad Beekeeping Blog 
Hi Ron. Are you aware of a study that shows that the neonic IMI, being systemic, travesl through a plant (red maple) in the xylem sap and concentrates in the leaves because of evapotranspiration. Very little in the pollen and nectar. Starting with p.52. https://archive.hshsl.umaryland.edu/bitstream/10713/2147/1/Johnson_umaryland_0373D_10323.pdf.
If I was a scientist, the first thing that I would do would go to Alberta and check the neonic levels in the leaves, nectar and pollen of the canola plants.
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Hi, Thanks for sending the link to the pdf: “The role of pesticides on honey bee health and hive maintenance with an emphasis on the neonicotinoid, imidacloprid”, a Ph.D thesis by J.D. Johnson, 2012. It’s a good read.
Dr Johnson’s sample sets are small (n=4, experimental; n=8, control), but the average uptake of IMI (the neonicotinoid, imidacloprid) was significant in the red maples which had soil treated or direct injections. The levels in leaves jumped from undetectable to 25 parts per million (though this involves n=4 trees and standard of deviation is 26 pbm). I noticed that p-values range from highly insignificant (.42) to highly significant (<.0001). None of this detracts from the fact that IMI was definitely taken up through the laced soil and through the direct injections into the maples’ trunks. Dr Johnson acknowledges the statistically small sample size, of course:
Dr Johnson tested red maple pollen foraged by honey bees to see IMI levels. Using 16 colonies taken from the ARS centre in Beltsville to the treated (and control areas) of red maples inside NYC. This part of the experiment involved trapped samples of red maple pollen, averaging 41.6% of the pollen. In soil treated areas, over a 3-year period, IMI was not detected in 9 samples of pollen, but was found at levels of 1.2 to 30.6 parts per billion in 8 pollen samples. Of this, Dr Johnson says, “The average [IMI]s in pollen from both soil and trunk injected trees are low enough not to be of concern to honey bee health.”
Finally, Dr. Johnson’s PhD thesis sums up:
Dr Johnson’s research then involves studies of sub lethal IMI effects on honey bees. At 100 ppb IMI added to pollen supplements, she finds unconvincing results. It seems adults may spend less time per larvae in the hive with this dosage, but no other irregular adult behaviour. (Such larvae were followed through adult life and found to be normal.) Dr Johnson also finds, “IMI exposures to honey bees through pollen under environmental real-world conditions may be allayed somewhat.” – meaning that it’s unlikely bees are carrying enough pollen or nectar in damaging amounts of neonicotinoid imidacloprid. However, Dr Johnson cautions that over the years, IMI may reach levels in the environment that could eventually hurt honey bees.
Now, to get to the comment you made about Alberta and our canola plants. I have never seen studies about neonicotinoids in Alberta pollen or nectar. However, it must be present in canola leaves because it kills the striped leaf beetle that would destroy canola crops. They eat the leaf, they get the poison. Dr Johnson tells us that in NYC red maple, most samples had no detectable IMI and where it was detected, amounts were 1.2 to 31 ppb (50% lethal level is 280 ppb). On the basis of no known bee losses due to neonicotinoids in Alberta, it’s likely Dr Johnson’s conclusions are correct. Neonics have been used here for 20 years. Most commercial beekeepers in Alberta would like to see their use continued because the alternative is known to kill bees. Without neonicotinoids, farmers would be using pesticides that wipe out bees by the million.
I am not saying that I’d like to see neonicotinoids continue forever. Eventually, it may build up in the soil enough to reach levels that will be lethal. I’d like to see biological treatments developed to arrest pests like the striped leaf beetle that farmers are poisoning. But, in the meanwhile, Alberta beekeepers make 200 pound averages year after year with 15% winter losses and no CCD. I know that this could change in a season. You make a really good comment, “If I was a scientist, the first thing that I would do would go to Alberta and check the neonic levels in the leaves, nectar and pollen of the canola plants.” Maybe someone like Dr Johnson will do similar research as her New York City maple tree study, but make the study on the vast scale of Alberta’s 300,000 colonies and western Canada’s millions of acres of canola.
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