To me, this paper seems very misleading.
Am I misreading something?

> "Synergistic toxicity was observed in the binary mixture of chlorothalonil

> with fluvalinate at the concentrations of 34 mg/L and 3 mg/L,
respectively;"

I through that 34 mg / Liter and 3 mg / Liter had to be typos, but they
weren't.
34 mg / Liter is roughly 34 parts per MILLION, roughly 34,000 parts per
BILLION. 

> "whereas, when diluted by 10 fold, the interaction switched to
antagonism."

OK, so "when diluted by tenfold" the still very high level of 3,400 ppb (3.4
ppm) fungicide  does not create any synergistic effect with the miticide.
Further, the interaction between the two is actually antagonist, so that's a
good thing for the bees, as one reduces the toxicity of the other.

But what prompted testing at such extremely high levels?

Quoting the paper:
"According to the survey of pesticide residues... 95th percentile values
(levels at which only 5% of detections are higher) in trapped pollen samples
were 0.3 mg/L (0.3 ppm) fluvalinate, 0.8 mg/L coumaphos, 0.15 mg/L
chlorpyrifos, and 3.4 mg/L chlorothalonil"

So, there appears no justification for a 34 mg/L dose of chlorothalonil, as
it is 10 times the 95th percentile dose found in the field.

I think it is stretching things just a tad to assume that comb might absorb
so much fungicide over time to deliver such a high dose to a larvae.

There may be "synergistic effects" between combinations of fungicides and
pesticides and/or miticides out there, but does not seem to be one to worry
about, despite the title.

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html