David's blog posts tagged with 'pollinator'

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

Pesticides in “Bee-Friendly” flowers

Jun

01

Take a walk around your local garden centre and you will see a mouth-watering display of gorgeous plants on display. You might note that some are specifically labelled as bee or pollinator friendly, with a picture of a cartoon bumblebee on the label. The Royal Horticultural Society (RHS) provide a “Perfect for Pollinators” logo which can be added to the label of any of the long list of garden plants that they judge to be good for pollinators. If you like hearing the buzz of bees in your garden, and want to do your bit to help our wildlife, you might well be tempted. Indeed, I have often spent a small fortune myself on potted plants when I only went to the garden centre to buy a pack of vegetable seeds. The big DIY and supermarket chains are similar – somewhere by the main entrance you will see a range of colourful plants in plastic pots and trays, some of them labelled as bee-friendly.

            If, like me, you’ve ever succumbed to the temptation to buy these plants, you may be somewhat concerned by the results of our latest research. Here at Sussex University we have been busy screening the leaves, pollen and nectar of these plants to see if they contain pesticides. We bought flowering plants from a range of major outlets; Wyevale (the biggest garden centre chain in the UK) and also Aldi, B&Q and Homebase. We deliberately bought plants that are known to be attractive to bees and butterflies; most of them had a bee-friendly logo, often the RHS one.

We found that most of these plants contained a cocktail of pesticides, usually a mixture of fungicides and insecticides. I wish I could say that I was surprised by the results, but sadly I wasn’t, for this mirrors similar studies performed in other countries. Only two out of 29 plants contained no pesticides. Seventy six percent of them (22/29) contained at least one insecticide, and 38% contained two or more insecticides. One flowering heather plant contained five different insecticides and five different fungicides – a veritable toxic bouquet. Seventy percent of the plants contained neonicotinoids (insecticides that are notorious for their harmful effects on bees), commonly including the ones banned for use on flowering crops by the EU (for the technically minded, 38% contained imidacloprid, 14% contained thiamethoxam and one contained clothianidin). Enough detail; you get the picture. Plants sold as ‘bee-friendly’ plants are usually stuffed full of pesticides.

Just before our results went public, B&Q (who knew that out study was appearing imminently) announced that they were prohibiting their suppliers from using neonicotinoids on their plants from February 2018. This is of course a great step forwards; well done B&Q, next time I need some screws or shelving I will be heading your way, and I hope others do likewise. Once our results were out Aldi declared that they stopped using neonicotinoids in October 2016 (we bought the plants we tested from them in July 2016). Also great news.  

Homebase and Wyevale have so far declined to make any public comment, despite high profile articles about the work in the Daily Mail and Independent. The Horticultural Trades Association, which represents the gardening industry, has been less than positive (http://bit.ly/2rXM4sL). Firstly, they claim that the three neonicotinoids banned by the EU on flowering crops are not used in horticulture (which would seem to simply be untrue). They then go on to say the “industry works closely with government bodies and other stakeholders to uphold high standards of environmental management”. They say that the concentrations of pesticides we found are at “low levels”, that we only sampled from “a very restricted area of the country”, and they suggest that the presence of clothianidin in one plant shows that our samples were contaminated, since this product has never been approved for use on ornamentals. In other words, instead of engaging positively, they try to undermine and play down our work.

Let’s have a closer look at their criticisms. Firstly, the concentration of the pesticide is of course important. Modern analytical techniques are very sensitive and tiny concentrations can be detected. Perhaps the concentrations we detected are all too low to do any actual harm? For neonicotinoids, the concentrations typically found in the nectar and pollen of treated crops such as oilseed rape are in the range 1-10 parts per billion (ppb). Exposure to such concentrations has been found to impair bee navigation and learning, reduce egg laying, lower sperm viability, and suppress the immune system. In a study with bumblebee nests we found that giving them pollen with 6ppb of neonicotinoid reduced nest growth and resulted in an 85% drop in the number of new queens produced[1]. In the ornamental flowers, we found imidacloprid at up to a maximum concentration of 29ppb, clothianidin at 13ppb and thiamethoxam at 119ppb. In other words, concentrations far higher than those known to harm bees. The claim that we only sampled from a “very restricted area” is pretty absurd. It is true, we sampled from stores near Brighton, but these are huge chains with a national/international supply network. Are HTA really suggesting the problem is peculiar to East Sussex? On the presence of clothianidin and the suggestion that our samples were contaminated, HTA need to learn a bit more about pesticides. As well as being used as a pesticide in its own right, clothianidin is a breakdown product of the closely related chemical thiamethoxam. The Ageratum plant containing the clothianidin also contained much higher levels of thiamethoxam, presumably the product with which it had been treated. So, not evidence of contamination at all.          

            I would argue that, by quibbling over details and focussing on neonicotinoids, HTA are missing the bigger picture, as indeed are B&Q and Aldi. Neonicotinoids are undoubtedly bad for bees, but what about all the other chemicals? If I buy a plant to feed to bees I don’t want it to have been drenched with a pyrethroid or organophosphate insecticide either. Both are highly poisonous to bees (and organophosphates are exceedingly toxic to people too). Even some of the fungicides have been found to harm bees[2]. If I’m buying plants to encourage wildlife, I don’t want the lingering worry that I might be accidentally poisoning my bees, hoverflies and butterflies. I don’t use any pesticides in my garden – I simply don’t need them. I don’t want to bring them in accidentally.   

            It is a shame that the horticulture industry seems largely unwilling to engage over this issue. It is perhaps not surprising, since their track record is not great. They’ve been continuing to promote and use peat-based composts for many decades despite the ready availability of perfectly good alternatives (in case you didn’t know, peat extraction does terrible damage to peat bogs, exacerbates flooding and ultimately releases huge amounts of carbon dioxide into the atmosphere). With birds, bees and butterflies all in rapid decline (2016 was the worst year ever for British butterflies), we all need to be willing to admit our mistakes and change our ways. HTA and the big garden chains such as Wyevale could really help to make a difference if they wanted to. I’d be very happy to help if they would like some advice (Wyevale, how about launching a new organic range of genuinely bee-friendly plants?)

Until the gardening industry gets its act together, I’d suggest the following. If you must buy plants, buy from an organic nursery, or failing that from B&Q or Aldi. Better still grow them from seeds, or if you haven’t the patience, plant swap with your friends and neighbours (if anyone wants some comfrey roots and lives near E Sussex I’d be happy to give you some, pesticide free, it is a fabulous plant for bees). We really can make our gardens into havens for wildlife, but not by driving to the garden centre to buy pesticide-laced plants grown in peat-based compost inside disposable plastic pots.    

 -----------------------------

Our research describing in detail the pesticides we found is here: http://www.sciencedirect.com/science/article/pii/S0269749117305158 

It was published in the journal Environmental Pollution, May 2017. 



[1] Whitehorn et al. 2012, Science, 336: 351-352.

[2] Bernauer et al. 2015, Insects 6: 478-488