Field Tests For Pesticides:
How Robust Are They And Do They Protect Bees?

In the UK, we are constantly told that field studies for pesticides offer the favoured and realistic method of assessing risk of pesticides to bees. In contrast, doubt is often cast over independent laboratory studies.

On 13 September, Defra published an analysis of the results of its review of research done earlier in the year on the effects of neonicotinoid pesticides on bees. DEFRA is the UK Department For Environment, Food And Rural Affairs. It relies on various departments to conduct different aspects of services that inform and support DEFRA, and two of these departments include FERA (Food And Environment Research Agency) and CRD (Chemical Regulations Directorate).

I read the report, and it was clear there was a regular theme running through the comments that CRD made with regard to the independent scientific studies, some of which were laboratory studies. I have included them on the right.

Can you spot the recurring theme?

Well, it seems at least Bayer Cropscience would agree with CRD. They also seem very keen to suggest that what is important is ‘What’s happening in the field” as demonstrated in their response to the Pettis study (below).

“I am sure there are some very interesting effects Dr Pettis has seen in the laboratory, but in reality, when you get to what’s important to everybody, which is what happens in the field, you don’t see these things happening.” – Dr Julian Little, Bayer CropScience; source: The Independent: 20/01/2011, Michael McCarthy).

So one wonders:

"just how good are regulatory field tests for pesticides, and do they protect our bees?"

Aside from the fact that some of the studies featured right, were at least partial field studies anyway, nowhere that I am aware of, do FERA/CRD/DEFRA justify:

  • Why field tests should be better than laboratory studies, especially given all the potentially uncontrollable variables in field tests.
  • How field tests for pesticides could, in a scientifically ROBUST manner, measure many of the potential effects being investigated by the laboratory studies, such as behavioural effects on bees.
  • What it is that makes the regulatory field tests for pesticides so reliable and robust, such that we can trust them above the independent data implicating that pesticides are harmful to bees.

…Afterall, their report also states:

“The regulatory field studies fully comply with current guidance and also cover some additional aspects, such as over-wintering. The power of the studies to detect statistically significant changes is not established and they would not show all of the specific sub-lethal effects suggested by academic studies. However, hives exposed to treated crops did not show any gross effects on a wide range of important endpoints when compared to control hives exposed to untreated crops”.


So How Robust Are Regulatory Field Tests For Pesticides?

Well, EFSA, the European Food Standards Authority, despite various controverial influences from industry, conducted a review: Scientific Opinion on the science behind the development of a risk assessment of Plant Protection Products on bees (Apis mellifera, Bombus spp. and solitary bees), and they have found many MAJOR weaknesses with the regulatory standards for the field tests for pesticides.


(find here - opens new window).

Weaknesses include, funnily enough, unrealistic field conditions, short duration of experiments, tiny fields (taking into account realistic foraging areas for bees), wishy washy flexibility regarding important elements of the tests, inability for the field tests to measure impacts on colony, behavioural effects, chronic effects and so on. I could go on and on. Check out the report for yourself.

But this did not surprise me, having read the guidelines myself. The field test guidelines EPPO170 are devised, it appears, by a group of pesticide manufacturers and those related to the industry (e.g. providing consultancy services), as well as a sprinkling of government civil servants, such as Helen Thompson and Selwyn Wilkins of FERA.

(see work of the EPPO - opens new window).

Note the quote:

"At the ICPBR- Bee Protection Group 10th Symposium (Bucharest, 2009-10-08/10.....the WGs (working groups) presented proposals for the revision of EPPO Standards, which were discussed in order to hear the expert comments and recommendations of all 79 participants and to reach a consensus."


So who were the 79 participants? They were mostly industry related people.....

(see pages 158 -159 - opens new window).



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CRD Response to Independent Tests:

Henry et al: A common pesticide decreases foraging success and survival in honey bees

“Due to the artificiality of the test design and dosing regime, there are uncertainties regarding the risk in a more realistic field exposure situation”.


Whitehorn et al: Neonicotinoid pesticide reduces bumble bee colony growth and queen production

“The key question for this study is how far it illuminates the likely real situation at field level - are the exposure and the resulting effects seen under normal conditions?”


Pettis et al: Pesticide exposure in honey bees results in increased levels of the gut pathogen Nosema

“The following points require consideration in trying to interpret this study: whether factors such as exposure are in line with field situations”.


Vidau et al: Exposure to sub-lethal doses of fipronil and thiacloprid highly increases mortality of honey bees previously infected by Nosema ceranae

“The key issue is how this relates to potential exposure under field conditions – i.e. will bees be exposed to this level of pesticide under field conditions?”


Wu et al: Honey bees (Apis mellifera) reared in brood combs containing high levels of pesticide residues exhibit increased susceptibility to Nosema (Microsporidia) infection

“There is no information regarding the relevance of the concentrations given to the bees – i.e. were the levels appropriate and/or realistic?”


Mommaerts et al: Risk assessment for side-effects of neonicotinoids against bumblebees with and without impairing foraging behaviour

"It is unclear as to the relevance of the concentrations tested and hence whether the results can be extrapolated to the field situation”.


Johnson et al: Ecological appropriate xenobiotics induce cytochrome P450s in Apis mellifera

“the issue of detoxification and the relevance of diet should be considered under realistic field conditions.”


Schneider et al: RFID Tracking of Sub-lethal Effects of Two Neonicotinoid Insecticides on the Foraging Behavior of Apis mellifera

“the next logical step would be to employ this methodology at the field scale to see if the effects observed in this study were replicated under field conditions”.


Teeters et al: Using video-tracking to assess sub-lethal effects of pesticides on honey bees (Apis mellifera L.)

“As regards the effects seen, it is important to note that they need to be related to what is likely to be encountered either in the hive (i.e. were the rates used realistic in terms of exposure to tau-fluvalinate) or in the field (i.e. were the rates used realistic in terms of what a worker honey bee is likely to encounter in the field.)”



Dr Chris Connolly,
University of Dundee (commenting on the
Sept 13th report):

“With respect to the criticism of the validity of all lab studies, past and future, in preference for the more relevant field studies, I consider this claim totally unprofessional and lacking all scientific credibility. Laboratory studies are the cornerstone of all therapeutic drug discovery as they provide a mechanistic description of events that can be controlled and tested experimentally. These studies identify real and quantified threats. In contrast, field studies are performed in a particular context with an uncontrolled surrounding area. What may be found at one site could be irrelevant to that found at another site. This is especially important given the multiple stresses to which our pollinators are exposed and the likelihood that multiple threats contribute to the pollinator decline. It is true that a laboratory based mechanistic explanation does not confirm that these effects are largely responsible for the pollinator decline. This will require countrywide bioinformatics once we know what pesticides have been used. An isolated field study has limited value”.