You asked about legal limits for imidacloprid residues.
Hi Bob and All

You asked about legal limits for imidacloprid residues.  A note first: I *do* accept that imidacloprid is safer for man than the OPs that it and other neonicotinoids replace, and as a crop scientist I'm well aware that there is a place for pesticides in production systems.

So, are the levels from this 1998 decision still in force?

http://regulations.vlex.com/vid/pesticides-raw-commodities-imidacloprid-23415850

'This rule extends the time-limited tolerances for residues of the insecticide imidacloprid and its metabolites in or on the citrus fruits crop group at 1.0 part per million (ppm), dried citrus pulp at 5.0 ppm, beet roots at 0.3 ppm, turnip roots at 0.3 ppm, and turnip tops 3.5 ppm for an additional 18-month period, to June 30, 2000.'

Perhaps they are, as this document updated limits for imported produce in Canada in 2004.

http://canadagazette.gc.ca/archives/p1/2004/2004-09-25/html/reg3-eng.html

'... 3 p.p.m. in sour cherries, sweet cherries and tomato purée, 1 p.p.m. in blueberries and tomatoes, 0.5 p.p.m. in apples and cucumbers, 0.3 p.p.m. in potatoes, and 0.05 p.p.m. in mustard seed and rapeseed (canola), and at 3.5 p.p.m. in brassica crops, 1.5 p.p.m. in grapes, 1 p.p.m. in citrus fruits and peppers, 0.6 p.p.m. in pears, 0.2 p.p.m. in mangoes, and 0.05 p.p.m. in cottonseed oil ....'

I'm sure that everyone reading this will know to add three zeros to convert ppm to ppb.  I guess that I should try hard to keep the bees out of my fridge?

The arguments in Europe have been around levels in arable crops of around one to a few ppb - levels that I think are, probably, safe.

As far as I can tell from reading around last night, in the UK there is approval for thiacloprid for sprays for fruit trees, but no sign of these granular soil treatments and concentrates for the injection into trees that seem to be at the root (sorry!) of these concerns.

Just to re-iterate, such levels in for example citrus fruit, if coming from soil treatment or maybe tree injection, would imply multi-season contamination and therefore flowers with very high levels too.  Randy, for whom I have the utmost respect, suggested that bees de-toxify imidacloprid.  They may do so, but there is plenty of published evidence that imidacloprid really is toxic to bees, so I can't see how the production systems that generate these pesticide loads in produce can be benign for pollinators.

all the best

Gavin

PS Paul: I'm not saying take it off the market, I'm saying make sure that the uses are safe *before* approval rather than afterwards.  And yes, beekeepers abusing pesticides themselves should be pursued and prosecuted where appropriate.


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