Large % of hives Nosema Positive

[MuswellMetro]

I have helped to run a Nosema testing evening and this Saturday afternoon, it was a free Nosema testing for our members, just bring 30 to 50 forager Bees

Nosema was present in 75% of the hives tested and in some areas 100% of the hives where quite severely infested .

Hives infected last year and treated wth fumidil B stilled showed signs and one that although treated but had no comb change was quite bad

We have now invested in two X400 magnification microscopes for our member to borrow in order to test in future

 

[beeno]

I have helped to run a Nosema testing evening and this Saturday afternoon, it was a free Nosema testing for our members, just bring 30 to 50 forager Bees

Nosema was present in 75% of the hives tested and in some areas 100% of the hives where quite severely infested .

Hives infected last year and treated wth fumidil B stilled showed signs and one that although treated but had no comb change was quite bad

We have now invested in two X400 magnification microscopes for our member to borrow in order to test in future

Hi there,
What do you mean by comb change? Seems to me you are doing a good job there!

 

[Tom Bick]

I have helped to run a Nosema testing evening and this Saturday afternoon, it was a free Nosema testing for our members, just bring 30 to 50 forager Bees

Nosema was present in 75% of the hives tested and in some areas 100% of the hives where quite severely infested .

Hives infected last year and treated wth fumidil B stilled showed signs and one that although treated but had no comb change was quite bad
We have now invested in two X400 magnification microscopes for our member to borrow in order to test in future

Hi MM Fumidil B was good to treat infected colonies as we know but no good in stopping them getting re-infected from a number of sources, bees drinking from contaminated water and perhaps in this case contaminated comb.

It may be that North London may be getting a bit of a problem with Nosema and hope you can get a hold of it or it will be a pain for years to come. Regular checks through the year is a good start and teaching how simple to test is also great and hope you can get plenty of beekeepers up for it. It’s a good thing that you ran the testing day.

 

[Nic Rhodes]

Nosema is a big problem up here as well, probably with similar infection rates. Each year we have a disease day and keep it current but although everyone is happy treating / dealing with Varroa, there still seems to be a pratical reluctance to deal with Nosema. I suspect the majority of my losses in the last 5 years are Nosema related rather than other causes.

 

[alanf]

...Each year we have a disease day and keep it current...

No idea how widespread sampling is, but many around here were checking for Nosema about now with a view to dosing the autumn feed with fumidil b. No more fumudil b, so the advice on beebase is "Instead of using medicines for treatment of Nosemosis, beekeepers should to maintain their colonies in good health...". Well, thanks a lot. That's not where we are when faced with a Nosema riddled colony in September. The next beebase suggestion is young prolific queens from "more tolerant stocks", most of those will already be occupied in their own colonies by now I'd have thought. Other sources suggest Bailey comb changes, another non option this time of year.

Best strategy now is what? Adding a little thymol mix to the feed? Some evidence it helps and in the NBU advice to prevent mould but not for countering Nosema.

Always valuable to know your enemy but I'm wondering how worthwhile Nosema sampling this time of year is any more. Ensuring they are fed enough to survive the winter is what we're generally doing anyway. It's counter intuitive to further handicap struggling colonies in spring by taking samples for Nosema checks but it might be the only realistic strategy we have.

 

[Tom Bick]

Hi Alan sampling at this time of the year better than nothing but sampling during the active season is the right way to go especially if colonies are not performing as well as expected.

There are a few papers testing the effects of thymol in the syrup that have shown good results with nosema not as good as fumidil b on infected colonies but very effective on reducing colonies becoming infected.

Personally I am glad fumidil b has gone as it seemed to me people just gave it to bees just as a precaution without first testing or suspecting anything was wrong.

 

[Nic Rhodes]

I use a four pronged attack against Nosema. Regular comb change, Thymol syrup, Fumidil B and 'oxalic' deployment or not. This is needed throughout the year rather than just september. By the latter 'oxalic' I mean that if I suspect serious Nosema still (especially if small colony) then I skip Jan 1st oxalic acid treatment even if they might need it. If I have a nosema positive hive I consider the apiary as positive, not just the hive. Thymol and Fumidil B are both effective but work in different ways on Nosema.

 

[Arfermo]

All very well suggesting use of Fumidil B but it's not readily available now as the company that made it found that the expense of complying with all the EU(?) regs made it economically unviable and has stopped marketing it, even at the price that used to be charged. Personally would prefer comb changing at least on a two yearly basis and best by shook swarm as it get it over and done with immediately. Bailey takes too long for me.

 

[Spadaman]

Best strategy now is what? Adding a little thymol mix to the feed? Some evidence it helps and in the NBU advice to prevent mould but not for countering Nosema.

Not sure this is correct. Search for Thymol treatment using the Search function - lots of scientific and anecdotal evidence that thymol in syrup reduces occurence of Nosema far more that fumidil b . This was copied ( for reference ) from a posting on this website but I don't have to hand the name of the original poster.

"I have done a fair bit of searching on treatments for Nosema, I came across a 3-year study done at Ege University in Turkey in 2002. They compared the effectiveness of Fumidil-B and Thymol. To summarize the results:

2002 First Year of treatment:
Fumidil-B, 55 colonies - Avg. 4.98 million spores per bee
Thymol, 55 colonies - Avg. 5.06 million spores per bee
Untreated, 52 colonies - Avg. 5.14 million spores per bee

2003 Second Year of treatment:
Fumidil-B, 40 colonies - Avg. 3.8 million spores per bee, Winter loss: 15 colonies (27%)
Thymol, 53 colonies - Avg. 2.8 million spores per bee, Winter loss: 2 colonies (4%)
Untreated, 31 colonies - Avg. 6.0 million spores per bee, Winter loss: 21 colonies (40%)

2004 Third Year of treatment:
Fumidil-B, 32 colonies - Avg. 3.7 million spores per bee, Winter loss: 8 colonies (20%)
Thymol, 51 colonies - Avg. 0.6 million spores per bee, Winter loss: 2 colonies (4%)
Untreated, 15 colonies - Avg. 6.7 million spores per bee, Winter loss: 16 colonies (50%)

The effectiveness of Thymol appears to be much better than Fumidil-B. The lack of a short term effect on spore counts in the first year can be explained by the fact that Thymol works by inactivating the spore, whereas Fumidil-B works after the spore is activated so many of the spores that were observed in the first year of the Thymol group were most likely inactive (as is supported by the significantly better overwintering stats). There was further evidence of the effectiveness of Thymol in the first year when the Avg. worker counts, brood surface area and honey production are compared between the groups.

The indication of this study is that with Thymol you can reduce the Nosema to a level that will not cause re-infection in subsequent years. Fumidil-B will not bring it down to that level and will require that the colonies be continuously treated (it seems to lose effectiveness over time). In addition the Thymol group outperformed the Fumidil-B group during all years of treatment.

There are also several additional advantages of Thymol:

1. It retards moulds in the syrup and pollen substitute.
2. It has been shown to have a repellent effect on the Small Hive Beetle (IMHO, this is because it retards the growth of the yeast that SHB infect the pollen with that helps attract them to the hive)."

I have been using Thymol in syrup primarily to prevent fermentation and a recent test for Nosema on one of my hives showed no infection. Maybe a coincidence or not but I will be using Thymol routinely in feed and as a varroa treatment ( using Hivemakers recipe).

Hope this helps.

 

[Poly Hive]

The presence of Nosema in colonies is certainly not new, it is pretty much a constant background infection, which under stress takes off to the detriment of the bees.

It's normal.

PH

 

[mbc]

The presence of Nosema in colonies is certainly not new, it is pretty much a constant background infection, which under stress takes off to the detriment of the bees.

It's normal.

PH

Without doubt the best way forwards with regard to nosema is to let Darwin sort the more susceptible colonies out, tough to practice as a hobby beekeeper with only a few hives in the short term, but if we all only propagated from non susceptible colonies then the whole nosema issue would fade away into obscurity.

It was a good point made above about not doing a winter oxalic treatment on struggling colonies, it can often be the final nail in the coffin.