On Tue, 8 Sep 2009 22:32:51 -0500, Bob Harrison <[log in to unmask]> wrote:

>Pesticides are one of the four possible causes of CCD the CCD working group has 
published.

There are far more than 4 possible factors involved. The most recent work by Dennis 
vanEngelsdorp, et al, refers to *61 meaningful variables*. And, they concluded that there 
was *no evidence* supporting pesticides as causing or precipitating colony collapse.

* * *

Of the more
than 200 variables we quantified in this study, 61 were found with
enough frequency to permit meaningful comparisons between
populations. None of these measures on its own could distinguish
CCD from control colonies. Moreover, no single risk factor was
found consistently or sufficiently abundantly in CCD colonies to
suggest a single causal agent.

Chronic or sub-lethal exposure to agricultural- or beekeeperapplied
pesticides can weaken the honey bee immune system,
hampering the ability of bees to fight off infection. This study
found no evidence that the presence or amount of any individual
pesticide occurred more frequently or abundantly in CCD affected
apiaries or colonies.

This study suggests that future, longitudinal studies should focus on
monitoring parasite (varroa mite), pathogen, and pesticide loads
while quantifying pesticide tolerance in study populations. More
specific studies that investigate potential interactions among
pesticides and pathogen loads are also warranted. Levels of the
miticide coumaphos were higher in control populations than CCDaffected
populations.

Citation: vanEngelsdorp D, Evans JD, Saegerman C, Mullin C, Haubruge E, et al. (2009) 
Colony Collapse Disorder: A Descriptive Study. 
PLoS ONE 4(8): e6481. Published August 3, 2009

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