Does anyone remember Rachel Carson? More on pesticides and bees...

Jan

15

As part of a project to study impacts of pesticides on bumblebees, we have recently been surveying what chemicals the local farmers in East Sussex use each year. Perhaps I was naive, but I found the figures to be astonishing. Below, I’ve pasted a list of the chemicals applied to two fairly typical fields, one with winter oilseed rape, one with winter wheat, in a single growing season (2012/13). For both crops, it is a very long list.

I should stress that these are perfectly normal farms; not especially intensive, situated on the edge of the South Downs, an area of gentle hills, hedgerows and wooded valleys. Beautiful, rural England; Constable would have liked it here. But let’s look at it from a bee’s perspective, focussing on the oilseed rape, since this is a crop they will feed on when it flowers:

Firstly, the crop is sown in late summer with a seed dressing containing the insecticide thiamethoxam. This is a systemic neonicotinoid, with exceedingly high toxicity to bees. We know it is taken up by the plant, and that detectable levels will be in the nectar and pollen gathered by bees in the following spring. In November, despite the supposed protection of the neonicotinoid, the crop is sprayed with another insecticide, the charmingly named Gandalf. What harm could the wise old wizard possibly do? Gandalf contains beta-cyfluthrin, a pyrethroid. Pyrethroids are highly toxic to bees and other insects, but there should be no bees about in November so that is probably OK. The following May, when it is flowering, the crop is sprayed with another pyrethroid,  alpha-cypermethrin. Less than three weeks later, the crop is blitzed with three more pyrethroids, all mixed together, a real belt-and-braces approach. Why use one when three will do? The crop is still flowering at this point (it was a late year), and would be covered in foraging bumblebees and other pollinators.

In between, the crop is also treated with a barrage of herbicides, fungicides, molluscicides and fertilizers – 22 different chemicals in total. Most of these may have little toxicity to bees in themselves, but some, such as a group of fungicides (the DMI fungicides), are known to act synergistically with both neonicotinoids and pyrethroids, making the insecticides much more toxic to bees. On the final application date, when the crop is flowering, one of these fungicides (prothioconazole) is added to the tank mix with the three pyrethroids. Any bee feeding will be simultaneously exposed to the three pyrethroids, the thiamethoxam in the nectar and pollen, and a fungicide that makes these insecticides more toxic.     

We don’t know what impact all of this really has on them. The safety tests generally expose test insects to just one chemical at a time, usually for just 2 days, but in reality they are chronically exposed to multiple pesticides throughout their lives. The fact that we still have bees in farmland suggests that they must be pretty tough. More broadly, we don’t know what impacts all of this has on other pollinators, or wildlife in general. Industry would tell us that all is well. They would also tell us (and the farmers that they advise) that all of these applications are vitally important parts of crop production, and that without them food production would collapse. I have my doubts. Is this really how we want to see the countryside managed? Do we really want to eat food produced this way?

I think I might head home early and finish digging over my veggie plot. At least I can control what goes into that.  

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Winter Oilseed Rape

Date

Type of compound

Brand name

Active ingredients

Application method

25/08/2012

 

Insecticide and fungicide

Cruiser

280 g/l thiamethoxam, 8 g/l fludioxonil and 32.3 g/l metalaxyl-M

Seed dressing

Herbicide

Shadow

Quinmerac, Dimethenamid-p, Metazachlor

Spray

Herbicide

Dictate

480g/litre bentazone as sodium salt in the form of soluble concentrate

Spray

Fungicide

Fiddle

Clomazone

Spray

08/09/2012

Molluscicide

Tds Major

Metaldehyde

Slug pelleter

12/09/2012

Herbicide

Shadow

Quinmerac, Dimethenamid-p, Metazachlor

Spray

10/10/2012

Fungicide

Crawler

Carbetamide

Slug pelleter

05/11/2012

Fungicide

Genie 25

Flusilazole

Spray

Insecticide

Gandalf

Beta-cyfluthrin

Spray

16/02/2013

Fertiliser

Double Top

Ammonium Sulphate and Ammonium Nitrate

Fertiliser spreader

Fungicide

Crawler

Carbetamide

Slug pelleter

Herbicide

Pilot Ultra

Quizalofop-P-ethyl

Spray

10/04/2013

Fertiliser

Nitram

Ammonium nitrate

Fertiliser spreader

22/04/2013

Fertiliser

Nitram

Ammonium nitrate

Fertiliser spreader

17/05/2013

Fungicide

Filan

Boscalid

Spray

Fungicide

Flanker

Picoxystrobin

Spray

Insecticide

Alert

Alpha-cypermethrin

Spray

05/06/2013

Fungicide

Propulse

Fluopyram, Prothioconazole

Spray

Insecticide

Hallmark Zeon

100 g/l lambda-cyhalothrin and 1,2-benzisothiazolin-3-one

Spray

Insecticide

Gandalf

Beta-cyfluthrin

Spray

Insecticide

Mavrik

Tau-fluvalinate

Spray

  

Winter wheat

20/09/2012

Insecticide and fungicide

Redigo Deter

50 g/L (4.3% w/w) prothioconazole and 250 g/L (21.4% w/w) clothianidin

Seed treatment

28/09/2012

Molluscicide

Tds Major

Metaldehyde

Slug pelleter

26/10/2012

Molluscicide

Osarex W

Metaldehyde

Slug pelleter

02/11/2012

Molluscicide

Tds Major

Metaldehyde

Slug pelleter

06/11/2012

Herbicide

Dictate

480g/litre bentazone as sodium salt in the form of soluble concentrate

Spray

Herbicide

Fidox

Prosulfocarb

Spray

Herbicide

Liberator

Flufenacet, Diflufenican

Spray

Insecticide

Gandalf

Beta-cyfluthrin

Spray

10/01/2013

Molluscicide

Tds Major

Metaldehyde

Slug pelleter

06/03/2013

Fertiliser

Sulphur Gold

Amonium sulphate-nitrate

Fertiliser spreader

08/04/2013

Fertiliser

Nitram

Amonium nitrate

Fertiliser spreader

23/04/2013

Herbicide

Quintacel5c

645 g/l (57% w/w) chlormequat chloride

Spray

Herbicide

Scitec

Trinexapac-ethyl

Spray

Fertiliser

Bittersaltz

Magnesium Sulfate

Spray

Fertiliser

Nutriphite Excel

Phosphate

Spray

30/04/2013

Fertiliser

Nitram

Amonium nitrate

Fertiliser spreader

07/05/2013

Fungicide

Bassoon

Epoxiconazole

Spray

Fungicide

Kingdom

Boscalid, Epoxiconazole

Spray

Fungicide

Bravo 500

Chlorothalonil

Spray

Herbicide

Quintacel5c

645 g/l (57% w/w) chlormequat chloride

Spray

Herbicide

Oxytril Cm

Ioxynil, Bromoxynil

Spray

27/05/2013

Fungicide

Adexar

Epoxiconazole, Fluxapyroxad

Spray

Fungicide

Bassoon

Epoxiconazole

Spray

Fungicide

Bravo 500

Chlorothalonil

Spray

19/06/2013

Fungicide

Cello

Prothioconazole, Spiroxamine, Tebuconazole

Spray

Note: These data were compiled from information provided by the farmer, by my wonderful postdoc Dr Cristina Botias-Talamantes. Keep an eye on this blog for more revelations from her ongoing work.

Dave Goulson's research lab website

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