NIAB - National Institute of Agricultural Botany

Orson's Oracle

The only good magpie is a...?

Posted on 06/12/2011 by Jim Orson

Back in the late 1950s, when I was about 12-years-old, the local NFU office gave you a crispy 10 shillings note for a dead magpie. Now 10 shillings (equivalent to 50p) doesn’t sound a lot, but then you could take a bus into town, go to the cinema, have fish and chips and still get home with change. Or is that the opening line from a Monty Python sketch...?

I also remember waking up to deafening dawn choruses. According to statistics it was the halcyon days of farmland birds.

Can these two observations be just coincidental? Did a lack of predators, like magpies, enable farmland birds to flourish? Or, are there other factors involved in the decline in farmland bird numbers over the past forty years? 

I’m now old enough to know that nothing is that simple, but there is now a vigorous debate on the role of predators with regard to the decline of farmland birds. As a non-expert reading experimental results and listening to both sides of the debate, I think those who argue for predator control have the stronger case.

However, resolving this issue appears to be challenging for the RSPB. Sometimes it seems that it is totally against predator control, and sometimes the charity appears to say that if you want to control predators then go ahead; after all predator control is carried out on some of the RSPB’s reserves. The lack of a clear message might be due to differing internal views.  And, of course, predator control could be unpalatable for many of those who support the charity organisation.

But as I suggested earlier, the decline in farmland birds is bound to be much more complicated than just a single factor.

Pesticides seem to be the first port of call by the media when any environmental problem is reported. The 1950s and 1960s were also the halcyon days of organochlorine and organophosphate availability. And there’s proof that some of these insecticides may have had a direct impact on bird fertility, including reducing the thickness of egg shells. DDT was also used as a herbicide as late as the mid-1970s; in wheat DDT could control susceptible barley varieties.

The generally agreed position is that pesticides didn’t directly contribute to the decline in UK farmland bird numbers. However, one of the major factors in the decline has been land use change facilitated by pesticides.

I was reminded of the extensive availability of organochlorine and organophosphate insecticides in the late 1960s and early 1970s by reading the 1970 Approved Products for Farmers and Growers Guide. Someone lent me it as a result of my previous blog ‘What’s in a name?’ I hope say more about the contents of this publication at a later date.

By the way, as I walked back from the paper shop this morning there were five magpies standing on the road...

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Candidates for confusion?

Posted on 28/11/2011 by Jim Orson

Well it seems a good idea in theory.  The new EU pesticide legislation includes the concept that where there are a few products available for a particular use then only the least hazardous ones should be authorised.  The legislation accepts that the products that remain authorised should be significantly safer than those that are not-authorised.  In addition, there should not be a significant economic disadvantage to the withdrawal of authorisation of products and that resistance management and product availability for minor crops should be considered.

There are two stages to this process.  Firstly, identifying those active substances that could be withdrawn because they may be significantly more hazardous than the alternatives for the same use.  These are called Candidates for Substitution and are selected by the European Authorities.  Secondly a Comparative Assessment is performed when an application for a product containing an active substance approved as a Candidate for Substitution is made.  This is done at the Member State level because the decision will depend on what products are locally available.

The European Authorities have to define the list of Candidates for Substitution by the end of 2014. The process for their selection is not yet completely clear nor is the process of how Comparative Assessment will be done in practice!  However our CRD have had a go at identifying possible Candidates for Substitution based on the information they have on the possible criteria.  In this study, virtually all the most effective black-grass herbicides in cereals are Candidates for Substitution.  Well, virtually all those that they expect to clear the first hurdle and get approved under the new EU legislation!

There is growing realisation that this process may be too difficult to introduce into practice.  There are several issues to resolve in practice, including:

• What does ‘significantly more hazardous’ mean?
• Once active substances are approved under the higher standards of the new legislation, will there be products based on these that are significantly more hazardous than others?
• Will all active substances have to be approved as meeting the standards of the new EU legislation before this process can kick in (this will mean no decisions on substitution before 2021)?
• How many active substances or modes of action are required for effective resistance management?
• How to define a significant economic impact?
• Finally and perhaps most significantly, will the process withstand legal challenge because of the difficulty of translating this process into practice?  There is now an example where there has been a successful legal challenge to the non-approval of an active substance in the EU.

Hence, after much heat and energy will this process become a candidate for confusion?

There is the option in the legislation that all pesticides for a particular use could be withdrawn if there was a non-chemical option available.  This reminds me what a former chairman of the Government’s Advisory Committee on Pesticides once said.  He had calculated from the record of the instances of farm deaths that if herbicides were banned and replaced by mechanical weed control there would be an extra 6 or 26 deaths/annum (I cannot remember which of the two, but you get the drift).  And he should have known; he was a Professor of Morbid Pathology.

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What’s in a name?

Posted on 23/11/2011 by Jim Orson

I remember speaking to a soft fruit grower in the early 1970s about the early days of pesticide use. There appeared to be no regulation. He claimed that he fed his treated crops to rabbits on the evening before marketing and went ahead and sold the produce if the rabbits appeared to be fit and well the next morning. Apparently, they always appeared to be fit and well!

Then things got a bit more complicated. Those who have been around the industry will remember the orange book of Approved pesticide products. It was quite a volume and was distributed free every year by MAFF. The last edition was in 1985 when the old Agricultural Approvals Scheme came to an end. This was a voluntary scheme where the efficacy of a product was Approved. These products were based on pesticides that had been ‘cleared’ for use.

The system was replaced by a system that included a statutory assessment of the efficacy of products. Eventually this was superseded by the EU directive 91/414 but the word ‘approval’ still had resonance as being a product whose efficacy had been independently validated.

The new EU regulation on pesticide registration came into force in June this year. It has resulted in a multitude of changes on how pesticides will be assessed. Unfortunately, to say the least, many of these changes will not be nailed down for two or three years. This uncertainty is not good for those seeking to get active ingredients registered or re-registered.

However, one simple thing has changed. The word ‘approval’ now means something different. Now active ingredients will be approved for use in the EU and products based on approved active ingredients will be authorised. After forty years of using the word ‘approved’ for products on the market this is going to get some getting used to.

I still have a copy of the 1985 Approved products book…

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