Imidacloprid and the Vanishing Bees

Joe Shaw
Wed, 25 Apr 2007 15:23:54 PDT
Hi Gang,

The recent news about honey bee colony collapse disorder and imidacloprid is 
interesting.  We know for sure that pesticides can have unintended effects, 
but imidacloprid is fairly new and maybe still an "unknown."  It would be 
sad if it were causing problems worldwide.

A colleague recently told me an interesting story about imidacloprid and its 
use in Brazil.  Citrus greening disease is a serious economic problem in 
Brazil, Asia, and now the USA.  The bacterium that causes the problem is 
spread by an insect (Asian citrus psyllid).  The insects have spread around 
the world to many places where citrus trees are grown and they are spreading 
the bacterium (and hence the disease).  My colleague reported (anecdotally) 
that one of the controls (in Brazil) that is keeping the disease under 
control is based upon the treatment of huge tracts of citrus trees with 
imidacloprid; repeated applications of the insecticide controls the psyllids 
and hence prevents them from spreading the bacterium from tree to tree.

I don't know if the story about massive applications of imidacloprid to 
citrus groves in Brazil is true.  However, in this country, nurseries are 
encouraged to produce clean nursery stock through the use of systemic 
insecticides (and by other means as well).  Additionally, imidacloprid is 
widely used on many other crops.

I did not find information about total imidacloprid use in the US, or 
worldwide; perhaps such information is pre-tabulated and easily obtained.  I 
did find numbers for California in 2005.  The report stated that 163, 618 lb 
of imidacloprid was used over 1,200,738 acres.  The largest single use was 
for structural pest control (control of termites).  Lettuce crops got the 
most imidacloprid, but grapes were high on the list as well as cotton and 
"general" vegetables as well as citrus crops.  I think the data is for 
agricultural use and does not include home use, use on ornamentals around 
buildings, or turf use.   I suspect total use was much greater than 1-2 
million acres.

Biology and nature are complicated; when you toss in agriculture and 
horticulture who knows what will result.  Overall, you and I probably eat 
imidacloprid as a trace component of many vegetables and fruits.  I hope 
colony collapse disorder is not caused by imidacloprid, and if so I hope 
humans don't acquire that particular problem.



Conroe TX

LINK:  Asian Citrus Psyllid

LINK:  Citrus Greening (Huanglongbing disease)

LINK:  California Pesticide Use (2005), Imidacloprid… 

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