The neonicotinoid saga continues

Jun

15

Yesterday saw publication of my review of the evidence for broader impacts of neonicotinoids on wildlife other than bees in the Journal of Applied Ecology. If you'd like to read it, please go to Goulson Lab publications page, scroll down, and click on the link to the pdf.

The key points are as follows:

1) Neonicotinoids are very widely used, and have extremely high toxicity to all insects and many crustaceans. They are commonly applied as a seed dressing to crops.

2) Most (<90%) of the active ingredient do NOT go into the crop, but get washed into the soil and ground water. They also leach into streams. Levels found in streams and California and the Netherlands commonly exceed lethal concentrations for aquatic wildlife. Data from UK waterways appear to be absent.

3) They have a half life in soil which commonly exceeds 3 years, meaning that they rapidly accumulate in soil if they are used annually. The effects of this on soil organisms and soil health are not understood.

4) Neonicotinoids have been found in field-margin vegetation, which is hardly surprising if they are accumulating in soils. Impacts of this on farmland wildlife such as butterfly caterpillars feeding on field margin vegetation have not been studied.

5) If dressed seeds are consumed by granivorous birds such as partridge, or by rodents such as voles, they need only eat a few seeds to recieve a lethal dose. During drilling, seed is inevitably spilled, but we do not know whether it is consumed by wildlife.

6) Evidence that neonicotinoid seed dressings actually increase yield is absent (or is not available for public scrutiny). Some US studies suggest that they have negligible benefit to farming. In short, modern farming practices do not seem to be EVIDENCE BASED, but are driven by marketing by the agrochemical industry.  

7) We seem to have forgotten all about Integrated Pest Management (IPM), an approach which emphasizes minimising pesticide use through monitoring of pest numbers, crop rotations, encouraging natural enemies etc... Instead we are simply using pesticides prophylactically.  

Although I supported the 2 year moratorium on use of neonics, which comes into effect in December 2013 (better than nothing), it is entirely unclear what it will achieve, or what will happen afterwards. Neonics will continue to be used extensively for non-flowering crops such as winter wheat. Even if we completely stopped using them they would be in soils for years to come. So any benefits from the partial moratorium will not be apparent in 2 years. In any case, there seems to be no plan to monitor the benefits, so if they did occur (which is unlikely) we wouldn't know.....

It is hard for most of us to make sense of what is going on here.....

 Dave Goulson's research lab website

 

  

 

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