I put sticky boards under most of the hives last weekend, and pulled them for a mite count this evening. You may recall (if you watched the videos below) that I treated two hives with Apiguard because they had high mite counts, and treated the rest with powdered sugar.
Well... either I didn't do a good job of thoroughly powdering each hive, or powdered sugar just flat doesn't work. Apiguard, on the other hand, seems promising.
Here are the results. In parentheses are the counts from July 28:
1- 37 (106)
2- can’t place board, need to elevate hive.
3- Too many to count! Hundreds! A carpet of mites! (20)
4- 55 (6)
5- 66 (17)
6- 50 (111)
8- didn’t check; need to make another sticky board
So, the two hives I treated with Apiguard--- #1 and #6--- saw a reduction of roughly 50-66%. Pretty good.
The hives treated with powdered sugar simply exploded. Hive #3 was insane; the sticky board was carpeted with mites. Interestingly, I had noticed yellow jackets preying on fallen bees in front of that hive this weekend. I thought it was just drones being kicked out for the year, but now I'm thinking they were drones--- and maybe workers--- weakened by mite parasitism.
Obviously, I'm going to treat all the affected hives (except 1 and 6) with Apiguard asap; probably Friday AM.
Apiguard, by the way, is a thymol-based solution. Thymol is an essential oil, not an insecticide. While you should not pull honey during Apiguard treatments, it's okay to place supers and pull honey immediately afterwards, that's how benign it is.
As for #1 and #6- I'm gonna give powdered sugar another try, this time with a bellows applicator I just bought. I've read mixed reviews on how these work; but I'll give it a shot. Maybe it'll be more effective than just shaking the sugar from the top. Since I just did a full treatment with Apiguard on these two, I don't want to repeat that this soon.
If I can talk my fearless videographer into showing up next weekend, I'll have some video of the process.