soft options for managing varroa

[peterdbk]

The picture you posted for 16mar12 showing all that 'smoke' looks to me like a FGMO fogging operation. The fogging tool is a propane-powered pesticide fogger (for backyard mosquito control). New Hampshire beekeepers had Dr. Rodriguez come up and present on FGMO and a lot of these foggers got bought shortly thereafter. My measurements of varroa drop through a screened bb did not show significant kill. The next winter, hive mortality was in the 90%+ ballpark in New Hampshire. One sideliner had good survival and gave credit to FGMO but it turns out he pulled drone brood combs on a regular basis and I think that is what deserves the credit. There are still some small-scale beeks in NH who use FGMO fogging and claim it works for them. AFAIK, no one has figured out what is special about their methods or situation.

I did some work with FGMO saturated napkins and determined that FGMO does, indeed, kill varroa. The napkins go in between the brood chambers so nurse bees have good contact with them. I remember counting hundreds of dead mites stuck to the underside of the napkins. I got adequate varroa control for a few years using FGMO napkins, but then it was not adequate control. I think what changed is the interaction of varroa with other pathogens (viruses) resulted in serious hive damage at lower mite infestation levels. My hypothesis is that any varroa hanging onto the underside of the bee will get coated with FGMO when the bee walks across one of these napkins. Any varroa that have managed to squeeze in between the plates on the bee's abdomen are sheltered and not killed. It takes a fairly high varroa infestation level (by today's standards) to get all the sheltered spots on the bees occupied and have varroa left over that have to ride exposed.

A couple of years ago there was some excitement about coconut oil to kill varroa. I recall an article in ABJ by Jerry Hayes that supposedly tested coconut oil and found in ineffective. That experiment used tiny applicators and IMO that rendered the experiment uninformative. There has to be enough oil delivered to get on all the bees. When I was using FGMO seriously, I was giving 4 thick napkins, soaked so they almost dripped, and refreshed every 10 days or so. These napkins
covered most of the boundary between the two broodnest deeps. I have not tested coconut oil using these thick napkins.

[Allen Dick]

> The picture you posted for 16mar12 showing all that 'smoke' looks to me like a FGMO fogging operation. The fogging tool is a propane-powered pesticide fogger (for backyard mosquito control).

I guess you are right. From the position in the article, I was hoping it was being used as an oxalic machine. Maybe it was. People are now taking a look at their units to see if that is possible.

> New Hampshire beekeepers had Dr. Rodriguez come up and present on FGMO

I met Dr. Rodriguez at the Virginai Beach ABF meeting. At one time, he was active on BEE-L.

Oil does kill mites, but the delivery method has been a problem all along. Dr. R started with waxed paper, then went to strings and on to fogging. (Actually, I might have been the person who first suggested the idea of using a fogger. If so, that would be in the BEE-L archives. http://community.lsoft.com/scripts/wa-L ... e?A0=BEE-L ). I've never experimented with using oil, though, since I was not hearing credible success stories at the time.

> A couple of years ago there was some excitement about coconut oil to kill varroa.

I recall a session in the main session devoted to the idea. It was unproven and not even tested at the time, and was, apparently, just one beekeeper's notion.

Oil kills mites, but to find a method that is reliable and scalable and not overly dependant on technique has been elusive.