I don’t know if you all get Bee Culture magazine or if you read all the articles, so I condensed an article on Nosema from the Jan 2010 publication.
Nosema Disease
Condensed from an article by Clarence Collison and Audry Sheridan in Jan 2010 Bee Culture.
Nosema disease is one of the most prevalent adult honeybee diseases and is caused by two species of microsporida. Nosema apis and Nosema ceranae.
Nosema is spread when adult bees ingest Nosema spores when they are eating contaminated food and when they are cleaning up fecal material from infected bees. The spores germinate within the midgut and release polar tubes that transfer their sporoplasm into the midgut cells where they generate more spores. A few weeks after initial infection the spores excreted with feces become new sources of infection in the colonies.
Although infected bees do not exhibit obvious disease symptoms, infection of Nosema causes digestive disorders, shortens the life span of honeybees, decreases population size of honeybee colonies and reduces honey production and crop pollination.
Nosema ceranae is associated with reduction in honey production and increased winter mortality.
Nosema free bees inoculated with 125,000 n. ceranae spores had a 100 % mortality rate in 8 days.
A study showed that bees infected with N. ceranae had a higher hunger level that leads to reduced survival and concluded that energetic stress is the probable cause of the shortened life span. It also indicated that infected bees have a reduction in the capacity to feed larvae royal jelly therefore the brood suffers.
Queens infected with active Nosema eventually ceased oviposition and became sluggish and the last batch of eggs laid often dried up in their cells.
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Ski’s note:
I was taught that you treat bees when you have a problem, and with Nosema Apis you will see bee poop in the hive or on the outside of the hive but with Nosema ceranae you will notice the problem when the bees are dead. Treating with Fumagilin-B in the spring and fall per the directions has reportedly taken care of both types of Nosema.
Jan 2010 Bee Culture Nosema Disease
I treat and have done my Fall treatments this year. Until I get a 400 power microscope or hear that treating may lead to resistence, I will treat. Since the ceranae version's manifestation is a dead hive in 7-10 days, and routine testing requires samples sent to labs, I am inclined to do at least Fall treatments. The bees are about to spend a great deal more time confined and in close quarters than they have spent in Spring and Summer.
I'm treating for Nosema as I stated in my post: Fall Treating with Fumidil-B.
The reason I believe in doing treatments:
http://guilfordbeekeepers.org/forum/vie ... ght=nosema
The reason I believe in doing treatments:
http://guilfordbeekeepers.org/forum/vie ... ght=nosema
Everyone has an opinion, this is mine.
Norma
Norma
Re: Jan 2010 Bee Culture Nosema Disease
For those that do not get or have time to read the bee magazines I thought I would list a few points that I thought were interesting in an article by Randy Oliver on Nosema in the January 2012 issue of the American Bee Journal.
Sick Bees part 15
American Bee Journal January 2012
Sick Bees by Randy Oliver
Interesting note - Young bees do consume pollen.
Randy Oliver questions weather spore counts can be translated into meaningful treatment thresholds because in a 50 bee sample a few highly infected bees skewed the spore count to an alarming level. This would be even worse in a 10 bee sample if one infected bee was included.
What may be a better way is to look at the infection rate of bees rather then an average spore count. It appears that the tip point for colony health occurs when more then about 40% of the bees in the hive become infected (a 40% infection rate). – It may be more important to determine the relative proportion of infected bees to healthy bees.
It appears that in order to make a decision whether to treat or not, that a couple of 5-bee samples should be adequate, interpreted as follows:
Zero infected bees in each sample – safe!
1 Positive bee in each sample – probably safe.
2 Positive bees in each sample - probably should treat.
3 Or more bees in each sample – that hive is in trouble.
What could be simpler than that?
The article continues to read as follows:
One huge assumption
All of these probabilities are contingent upon your taking a representative sample that reflects the overall infection rate of the hive. Would this be the case in real life? Would 5-bee samples give consistent results? I didn’t know, so I decided to put it to the test.
……I took samples of bees from the weakest hives in each yard, and later processed subsamples of 5 bees at a time.
The article reads:
Pratical application: I found the above a reality check instructive to say the least! In fact I could say that I learned more about the degree of Nosema infection in my operation in 3 hours of bee squashing then I’d learned in the last 4 years of counting spores! I doubt that I will ever do another spore count.
The article reads:
I love this method! For one. I learned that Nosema was only associated with half of my weakest hives, so I can now sleep a bit better. On the other hand, half of those weak hives did have high Nosema levels, so I need to address this (spot treatment?). I am now eager to go sample some strong colonies. What is also apparent is that the method worked remarkably well! Its not perfect, but it appears that I’d rarely miss an infection if I processed two samples of 5 bees for each tested hive. And the method readily picked out the really sick hive! Clearly this is only a preliminary test of the procedure, and needs to be repeated with a lot more hives, but the apparent accuracy of the method is very encouraging to me.
The article concludes:
The only remaining problem is that most beekeepers will choke at the thought of how much time it would take them to squash and microscopically view 10 bees out of each hive. And that leads us to: A neat Little Shortcut (to be concluded in the February 2012 issue)
Note – There is a lot more to this article and is very interesting to read, I just hit some of the high points. It reads like a great who done it novel. I can’t wait until February.
Sick Bees part 15
American Bee Journal January 2012
Sick Bees by Randy Oliver
Interesting note - Young bees do consume pollen.
Randy Oliver questions weather spore counts can be translated into meaningful treatment thresholds because in a 50 bee sample a few highly infected bees skewed the spore count to an alarming level. This would be even worse in a 10 bee sample if one infected bee was included.
What may be a better way is to look at the infection rate of bees rather then an average spore count. It appears that the tip point for colony health occurs when more then about 40% of the bees in the hive become infected (a 40% infection rate). – It may be more important to determine the relative proportion of infected bees to healthy bees.
It appears that in order to make a decision whether to treat or not, that a couple of 5-bee samples should be adequate, interpreted as follows:
Zero infected bees in each sample – safe!
1 Positive bee in each sample – probably safe.
2 Positive bees in each sample - probably should treat.
3 Or more bees in each sample – that hive is in trouble.
What could be simpler than that?
The article continues to read as follows:
One huge assumption
All of these probabilities are contingent upon your taking a representative sample that reflects the overall infection rate of the hive. Would this be the case in real life? Would 5-bee samples give consistent results? I didn’t know, so I decided to put it to the test.
……I took samples of bees from the weakest hives in each yard, and later processed subsamples of 5 bees at a time.
The article reads:
Pratical application: I found the above a reality check instructive to say the least! In fact I could say that I learned more about the degree of Nosema infection in my operation in 3 hours of bee squashing then I’d learned in the last 4 years of counting spores! I doubt that I will ever do another spore count.
The article reads:
I love this method! For one. I learned that Nosema was only associated with half of my weakest hives, so I can now sleep a bit better. On the other hand, half of those weak hives did have high Nosema levels, so I need to address this (spot treatment?). I am now eager to go sample some strong colonies. What is also apparent is that the method worked remarkably well! Its not perfect, but it appears that I’d rarely miss an infection if I processed two samples of 5 bees for each tested hive. And the method readily picked out the really sick hive! Clearly this is only a preliminary test of the procedure, and needs to be repeated with a lot more hives, but the apparent accuracy of the method is very encouraging to me.
The article concludes:
The only remaining problem is that most beekeepers will choke at the thought of how much time it would take them to squash and microscopically view 10 bees out of each hive. And that leads us to: A neat Little Shortcut (to be concluded in the February 2012 issue)
Note – There is a lot more to this article and is very interesting to read, I just hit some of the high points. It reads like a great who done it novel. I can’t wait until February.
Just some thoughts.