?> The image is at http://www.honeybeeworld.com/diary/articles/images/DSCF7708_1024.jpg and is a slide presented at the BCHPA meeting in Cranbrook recently....
Not surprisingly, fumagillan was the most effective of those tested at the arbitrary concentration chosen. There was no mention of consumption or mortality among the caged bees, so what you se is what you get and it is hard to draw conclusions, but some trends are apparent.
The concentration may not be not be optimal for many of the substances tested, and in some cases there may only be a window of efficacy, not a continuous progression from zero to max to toxicity.
For example, Nosevit recommends "A 500ml bottle is to be mixed into 44 gallons of "thin" or "light" syrup". These are not exact terms, so I'll guess that a gallon (US) of thin syrup weighs 3.78 l/gal x 1100 g/l = 4200 g.
If 500 ml of Nosevit weighs about he same as water (guessing again) then that recommended concentration is 500g in 184,800 g of syrup. (44 gal x 4200 g/gal = 184,800). That works out to ~0.003 or 3 parts per 1,000. The test shown on the slide uses 1mg/g or 1 part per 1,000, so it tests 1/3 of the recommended dose. (Why they did that is beyond me).
Beekeepers use thymol in syrup at anywhere from 1/4 to 1 g/US gallon. Using the same rough weight for thin syrup (beekeepers usually use thicker syrup) and 1/2g/gal, 0.5g/gal is 0.5g/4200g or 1000mg/8400g. That works out to 1mg/8.4g, not 1mg/g.
As for fumagillin, the recommendation from Medivet is 25mg (ai)/l ie. 25mg/1200g (thick syrup) or 1mg/48g, not 1mg/g. That appears to me to be a 48x overdose, but under the 75x safety factor claimed by Medivet. (No wonder it worked!)
Please check my math. I often make mistakes.
***********************************************
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
Guidelines for posting to BEE-L can be found at:
http://honeybeeworld.com/bee-l/guidelines.htm
|
