The Precautionary Principle

[EmsE]

Heres hoping for a pesticide discussion with a difference- it remains civil

There is a lot of talk about calling for the government to invoke the precautionary principle on the use of neonicotinoids.
I can fully appreciate the precautionary principle being utilised before a product is used and also in cases where for example, it was shown that the pesticide was a serious threat to the wild life- not just the honey bees and that by implementing it would have less of on impact than the chemical it's self.
From what I've read so far, and I have to put my hands up and say that it's not a lot as the tone of the threads tend to become unpalatable, everyone agrees that the neonicotinoids aren't good for the insects but it is the extent of the harm they cause that is under question.

So, we've had these neonics around for a good few years and unlike the former pesticides, colonies are able to thrive whether or not there are other effects going on that aren't immediately obvious. It is logical to assume that there will be some impact on the other insects, but again they're still present and are they going to suffer serious consequences if the precautionary principle isn't invoked immediately?

Those calling for the ban tell us that the soil is becoming infertile and the effects of these neonics will last for years. So, if there is an outright ban, how on earth do we grow our crops on this land if that is the case and what will the pollinators forage on? Surely a carefully managed plan on reducing the use of chemicals in our food chain whilst increasing the hedgerows & biodiversity would be better for all involved?
And the good old question than no one can escape from is what would replace the neonicotinoids?

[Bumble]

Those calling for the ban tell us that the soil is becoming infertile and the effects of these neonics will last for years. So, if there is an outright ban, how on earth do we grow our crops on this land if that is the case and what will the pollinators forage on? Surely a carefully managed plan on reducing the use of chemicals in our food chain whilst increasing the hedgerows & biodiversity would be better for all involved?
And the good old question than no one can escape from is what would replace the neonicotinoids?

I haven't read much of the background material either because it's all too much, but this wikipedia articles says that, "Independent studies show that while the photodegradation half-life time of most neonicotinoids is around 34 days when exposed to sunlight, it might take up to 1386 days for these compounds to degrade in the absence of sunlight and microorganism activity."

I don't know how true this is, I don't know it it's alarmist rubbish and I don't know of any counter-statements. I don't know the effect of seed coatings on micro-organisms and I don't know how deep OSR roots travel nor how far cemicals in seed dressings will migrate in the soil, if at all. I have seen oil seed rape feilds with plenty of weeds around the margins and plenty of rooks and crows looking for worms and grubs, so perhaps the long half life quoted is in sterile, laboratory controlled, conditions and not in the real outdoor world where the remains of crops are ploughed in and what was the root area is exposed to daylight in preparation for the next xcrop.

[gavin]

I haven't read much of the background material either because it's all too much, but this wikipedia articles says that, "Independent studies show that while the photodegradation half-life time of most neonicotinoids is around 34 days when exposed to sunlight, it might take up to 1386 days for these compounds to degrade in the absence of sunlight and microorganism activity."

I don't know how true this is, I don't know it it's alarmist rubbish and I don't know of any counter-statements. I don't know the effect of seed coatings on micro-organisms and I don't know how deep OSR roots travel nor how far cemicals in seed dressings will migrate in the soil, if at all. I have seen oil seed rape feilds with plenty of weeds around the margins and plenty of rooks and crows looking for worms and grubs, so perhaps the long half life quoted is in sterile, laboratory controlled, conditions and not in the real outdoor world where the remains of crops are ploughed in and what was the root area is exposed to daylight in preparation for the next xcrop.

I think that this is one area where Wikipedia isn't a reliable source. However it does seem pretty well established that neonics can have a long half-life in some situations. There is a need to be careful though. I remember apparent problems with rape after potatoes on Prince Edward Island when the application for potatoes was huge and the long half life gave problems for subsequent rape crops. Do we permit such applications? I suspect not for potatoes, but best be careful as it was pointed out just yesterday that it is possible to buy Merit Turf (5g/kg imidacloprid) granules to beautify and poison your lawns and golf courses. The point I was trying to make is that OSR seed is sown at a rate of 5kg per hectare, so the left-over residue gets spread into a large volume of soil (where it continues to break down slowly) and seems to me unlikely to give appreciable contamination in subsequent crops.

[EmsE]

Which crops do they use the neonics on in the UK? I've only seen reference to OSR and I understand there is a difference in the effects of the pesticides depending on when the crop is sown? Why would that be?

Is there a big difference in the type of neonics used?

[Jon]

There is a big difference.
Imidacloprid, Clothianidin and Thiamethoxam are more toxic to the bees than the others.
These are the 3 that are likely to face a 2 year suspension while further safety tests are carried out.

They are used on some crops such as potatoes and sugar beet which are of no interest to bees for either pollen or nectar.

They are also used on maize which bees occasionally visit for pollen but only when there is no better pollen on offer elsewhere.

Oil seed rape is the main treated crop of interest to bees and over 90% in the UK is treated with one or other of the neonicotinoids, increasingly thiamethoxam as opposed to Imidacloprid.

The curious thing is that these products have been used on oilseed rape for many years now and beekeepers report that their bees build up well on it. I have several fields of it right beside my main apiary most years and I have never had a problem with it.
I see Murray McGregor has reported the same over on BKF and he runs thousands of colonies.
There is also supposed to be a lower level of product in the pollen and nectar of the autumn sown oil seed rape as opposed to the spring sown stuff.

One thing to look out for is application method. Anything sprayed on is likely to be of much greater danger to bees than anything applied as a seed treatment.

[Bumble]

Sorry, I know Wikipedia isn't te most accurate of sources, but the massive list of Google hits is just too much to wade through, unless you know what you're looking for. There are too many scare stories too.

I live somewhere where there's virtually no crop growing as such, although there's a fair bit of livestock farming and hay and there are a lot of beekeepers. I know a some who keep colonies behind a cricket club, and I'd guess the pitch is treated with soemthing to get rid of cockchafers which can wreck an area of grass in no time at all. They've had their hives there for years without any problems.

It's the same with OSR. Not many beekeepers are idiots, and not many are reckless with their colonies. The old boys who've been doing it for years can tell almost instinctively if there's something wrong with their bees and they'd talk about it when they get together and write about it in the club newsletter. The only complaints I've ever heard ahve been about varroa, the viruses it vectors, and the weather being too cold for a summer, and too wet for too long so the bees couldn't get out. That's what they keep coming back to - 2010 was bad, 2011 was worse, and 2012 was the worst in 40 years. They do also talk, and write, about taking their bees to the rape. Some of them travel quite a distance. Why would they do this if it hurts their bees? Why should they take precautions when they see no need?

[gavin]

Here is another piece of the jigsaw. Provisional results from a large Canadian study (funded by Bayer, performed by respected bee scientists including Cynthia Scott-Dupree) of clothianidin-treated oilseed rape. As it is in Canada I would imagine that this is spring-sown oilseed rape. Canola according to the N Americans. Thirty scientists participating (well, 8 did the fieldwork), nearly $1m (Canadian), 40 colonies. Fairly small fields (5 acre, 2 ha), 10 fields 10 km apart.

http://www.producer.com/daily/ontari...ts-bee-deaths/

- Hives comprising bees that foraged on canola grown with clothianidin treated seed produced 52.8 kilograms of honey, while the control group produced 51 kg. Average Ontario honey yield in 2012 was 37 kg.

- There was no difference in colony weight gain between bees exposed to clothianidin and the control group.

- Dead bee counts, done over four assessment dates during canola bloom, showed 140 dead bees in hives exposed to clothianidin and 133 dead bees in the control group.

It is all still provisional but it does seem to indicate that even spring OSR, which was shown by the Poles (Pohorecka et al. 2012) to have a lot higher neonic residues than winter OSR, doesn't affect honeybees (deleteriously). I'm still sitting on the fence regarding bumble bees.

G.

[Trog]

"Independent studies show that while the photodegradation half-life time of most neonicotinoids is around 34 days when exposed to sunlight, it might take up to 1386 days for these compounds to degrade in the absence of sunlight and microorganism activity."

The doom-mongers might well go for the 1386 days figure without noting that that requires absence of sunlight and microorganisms. As far as I know, most crops are grown in sunlight - the more the better (though I grow mung beans in the dark, of course!).

[Neils]

That study will be discounted then because it was funded by Bayer and doesn't conclude that the bees are dying.

The media narrative remains that these are new pesticides rather than something that's been in pretty widespread use for nearly 20 years. It's also largely specific to Honeybees and them being the "canary in the coal mine" I'm still not seeing them as being any worse than what was in use before and specific to honeybees they largely seem to be significantly less worse when you look at known pesticide poisonings across Europe since their introduction. Yes there's a massive spike in Germany over the seed dust issue a few years back but if we continue to accept that the world isn't going to go Organic overnight then these do, on current evidence, seem to be the best of a bad lot from a honey bee perspective.

This campaign is very much limited to beekeepers even though the RSPB have weighed in with a rather wooly statement, and I wonder whether that is largely down to a lack of appetite, even if Neonics were/are laying waste to non target insects, to having pyrethoids etc coming back into use, as happened in France, which are definitely much worse for the wildlife that they're interested in.

[Jon]

I read an article about otters earlier today you might be interested in Neil.

Apparently they used to be seriously damaged by organochlorine pesticides, DDT and Endosulphans and others but these have been largely phased out. They face a new problem from Endocrine disruptors.