Hi all
We have been having a hearty debate on this topic both onlist and off. I want to be clear that my intention is to scrutinize what is known and what is not known, and the manner in which these assessments are made. We do not have a clear recommendation from any particular agency that we can follow, so it looks as if it's to each his own, which is a bit ridiculous, if nosema is a serious pest. The closest thing to a coherent recommendation is this from Ontario:
> Feed bees a mix of Fumagilin-B with sugar syrup in spring if you have a high level of infection (> 1 million spores/bee). This threshold may not reflect the current virulence of nosema. The University of Guelph (Townsend House) and the Tech Transfer Program are addressing the virulence of nosema through applied research.
In other words, check for nosema but we don't know what levels are significant. We'll get back to you on that.
In the recent edition of Beekeeper's Handbook:
> N. ceranae may not be cured with this medication, or the medication dosage may have changed; be sure to stay current on the most up-todate procedures. Research is still investigating whether doubling the amount of fumagillin is effective against N. ceranae, so check the current literature. Fall feeding may be more effective than spring feeding.
How to stay current, then? Where do we go for up to date information? Check with UC Davis:
Diagnosing and Treating Nosema Disease Eric C. Mussen, Extension Apiculturist, UC Davis – 3/11/11
> Nosema disease in U.S. honey bees is caused by one of two (or both) fungi named Nosema apis and Nosema ceranae. With Nosema apis, this spike in the level of infection normally occurrs in early spring, then "goes away" as the weather improves and the bees defecate outside the hive. With Nosema ceranae having become the dominant species, infection and spore levels can be elevated all year.
Off to a good start!
> Medicating for Nosema ceranae is going to be different. For one thing, fumagillin no longer is available as Fumidil-B®. A Canadian company, Medivet, sells the product as Fumigilin-B®. The new fumagillin mixes more readily into solution and it appears to be less stable in solution, if the label instructions are correct. The label suggests using the antibiotic in the fall, as always has been the practice at that time of year for nosema control.
> Since N. ceranae tends to persist throughout the year, the label calls for increasing the dosage level, and feeding repeatedly in small amounts of sugar syrup, in the spring. Beyond that, Spanish researchers have found that N. ceranae-infected bees tend not to take medicated syrup from feeders, so they had to pour the syrup over the bees (called "drench"), down between the frames, to make them consume the medication.
What what am I supposed to do? Buy the drug and do what the company says to do? What do they know about Nosema ceranae? If anyone has seen a clear recommendation in print, aside from Randy's stuff, I'd like to see it. If you are still reading, this is from Australia:
> As this is a relatively new parasite in European honey bees, the full effect of this species of nosema on individual bees and colonies is still being researched. It does not appear to cause sudden, quick losses of bees as does Nosema apis.
> N. ceranae can be detected in all four seasons, while N. apis occurs mostly in the milder seasons of autumn and spring. N. ceranae infection affects more cells in the honey bee gut than N. apis infection at the same temperature. Researchers have suggested that this difference may explain why there is a higher mortality of bees when they are infected by N. ceranae than when they are infected with N. apis. N. ceranae can kill bees faster than N. apis.
It doesn't cause sudden, quick losses? But it kills bees faster? I'll check back later, when you make up your minds!
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