My understanding concerning Nosema is essentially the same as Mr. Bach's.  I
recall some university research with proper controls, etc. that determined
(1) Nosema is endemic and only the worst cases are seen by the beekeeper;
(2) While spring feeding will control the Nosema, it is usually "too late"
to have a lot of effect on the honey crop (therefore beekeepers who have
tried it feel it does not have much benefit) and, (3) fall feeding will
increase the next year's honey crop (all things being equal) by truly
astonishing amounts.  I recall the increase at around 30%.
All that said, I have to admit I usually only feed my nucs with Fumidil-B in
the fall because my deeps are choked with honey.  So...I think I know
better, but don't do it anyways.
Can anyone help with the research references concerning the effect of fall
vrs spring feeding of Fumidil-D and both compared to not feeding at all?
feeding
-----Original Message-----
From: James C Bach <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Sunday, February 22, 1998 2:15 PM
Subject: Nosema, patties, and other things.
 
 
>To Bee-L colleagues:
>
>I hope this message doesn't cross the line for being too long for
>downloading.  But I think I have observed by the questions asked to the
>list that many beginning beekeepers are in the audience.  And some of the
>answers I read appear to be based on conjecture and the opinions of others
>rather than on the literature, data and experience.
>
>I would like to express a few ideas about how we approach Nosema and other
>issues regarding our bee colonies.  It is often heard among beekeepers that
>they do not have any problem with Nosema, or Honey Bee Tracheal Mites
>(HBTM), or brood survivability, or even queens.  But when they are asked if
>they had some bees checked in a laboratory for Nosema or HBTM, or if they
>measured brood survivability or queen quality, they say no.  I suggest that
>without a lab diagnosis or conducting measurements, we cannot tell whether
>our bees have these maladies, or whether they do not.  I base this opinion
>on the following grounds:
>
>a.  I have dissected thousands of bees for Nosema.  When I put the midgut
>into a petri dish I observe the difference between the color and distention
>or swelling of the midgut between the 25 midguts in the dish.  I only
>rarely see a midgut that is so swollen that I can't see the rings around it
>or one that is whitish in color.  Yet the samples will have between 4,000
>spores (the lower detectable limit) and as high as 3,500,000 spores per
>bee.
>
>b.  The four hives that had the 3.5 million spores were sampled in early
>July on Vashon Island in Puget Sound in western Washington.  They were
>managed in an excellent manner, were five deep boxes high and full of bees.
> They each produced a 125 lb. crop that year.  Was I surprised after all
>the stories I had heard about Nosema.
>
>c.  When we were running 250+ samples of bees for HBTM in the lab in 1985
>we checked all samples for Nosema.  The samples were taken in early June as
>I recall.  The Nosema levels in wet and rainy western WA samples didn't go
>over 150,000 spores per bee.  Only three samples from commercial colonies
>showed Nosema in dry eastern WA .  When I checked the location from which
>the samples came I found one apiary setting below the surrounding grade
>level in a gravel pit (very high chalkbrood levels too), another backed up
>against a southerly exposed granite rock bluff exposed to high temperatures
>day and night, and the third was in the bottom of a steep canyon which had
>a stream flowing through it.  I suggested that the beekeeper move the
>apiary out of the gravel pit.  He did so and the bees removed the
>chalkbrood in two days!  The observed condition of the colonies - vitality,
>temperament, brood survival - improved rapidly.  Nosema appears to be
>highest and have the most negative impact on queens and package bees
>following shipment, and colonies in the spring if one or more other
>maladies are affecting them.
>
>d. I have also cut thousands of thoracic disks of bees and put them in a
>potassium hydroxide solution to check for HBTM with a microscope.  In many
>of these cases I have removed the trachea from surrounding muscle tissue
>and looked at it for mites with a 10x hand lens before putting them in the
>chemical bath.  I found that often I didn't see mites with the hand lens
>but after clearing the muscle tissue for 4-6 hours in the solution I found
>between one and 10 mites per trachea.  My observations suggest that low
>levels of mites may be missed with a hand lens.
>
>e.  My experience has been that Nosema was highest in those colonies which
>appear not to build up rapidly in the spring, though HBTM causes the same
>symptoms nowadays.  But it is also true that reduced brood survivability,
>poor nutrition, and unattractive queens may all occur at the same time in
>the hive resulting in a slow building colony in the spring.  So now we have
>to measure several things before we can determine the cause of a
>symptom(s).  See how complicated these issues get?
>
>f.  Beekeepers often notice spotty brood patterns in their hives.  I have
>checked brood survivability under these conditions and found that only 35
>percent of the cells with eggs I had previously identified were dark eyed
>worker pupae 14 days later.  I have checked larval survivability in
>colonies over a period of time pre and post feeding of Fumidil-B
>(regrettably without testing for Nosema).  I found that pretreatment
>survivability ranged between 35 and 60 percent.  Treatment of the six to
>eight frame splits in mid May consisted of gorging the bees with four
>feedings poured over the cluster (rate of one tsp. of Fumidil-B in one
>gallon of 1:1 syrup); twice one hour apart on a 60F day, and two subsequent
>gorgings ten days apart.  Sufficient syrup was poured between the combs to
>moisten the bees without letting too much  run out the hive entrance.
>Three weeks post treatment, larval survivability ranged between 85 and 95
>percent.
>
>g.  Beekeepers say their colonies look excellent following the use of
>unlabeled miticides.  They don't know what the mite levels were before they
>treated.  When the right questions are asked, it is often found that they
>lost a lot of colonies the previous fall even after treating (using
>Apistan) because they let the mite levels get too high.  The remaining
>colonies contained young bees with low levels of mites.  The next spring
>they use an unapproved chemical, and report the bees looked fine all year.
>Of course they would, because of very low mite levels in the spring
>(perhaps entirely unaffected by the miticide).  Talk with them in the fall
>or the following spring and they report 30 to 40 percent losses.  They will
>claim the miticide worked because that is what is being commonly reported,
>and they look around for some other thing upon which to blame the losses.
>You'd be surprised at the stories I've heard.
>
>h.  Grease patties - TM or plain, powdered or granulated sugar.  Many
>beekeepers assume that bees eat the patty.  Others think that bees only
>remove the patty from the hive in response to hygienic behavior cues and in
>so doing they get some TM on their mouth parts which happens to get to
>larvae during feeding activities.  To my knowledge neither of these have
>been proven by research.  (But then there is so much research published
>that I can't possibly keep up with it all, and I don't have a formal
>research library at my disposal.)  I do know a beekeeper who fed large
>amounts of cheap powdered sugar to a bee colony for winter stores instead
>of syrup or honey.  The colony died in short order because powdered sugar
>contains cornstarch.  Powdered sugar holds a patty together better than
>granulated sugar during comb manipulations.
>
>You simply cannot evaluate a colony's health by looking at the bees, though
>you may be able to make some observations about the colony's condition.
>That is why scientists insist that research colonies be essentially equal
>in all respects, that treated and control colonies be used, and accurate
>measurements be taken, before any deductions may be made about the success
>or failure of a treatment.  But I will suggest further, that there are a
>significant number of things going on in the colony, like larval
>survivability, queen attractiveness, etc. that are also influencing the
>outcome of the treatments we apply.
>
>We attribute human behavior to honey bees, dogs, cats, and other animals.
>This is the source of many errant conclusions about what bees are doing and
>how they respond to what we are doing to them.
>
>It is also very import for beekeepers to check out the technical references
>available to them in their search for information about diseases and mites.
> Much has been published on the subject since 1983.  Where we have problems
>is in determining appropriate bee and hive management techniques for
>various conditions.  Here it is easy to get at least 11 answers from ten
>beekeepers on any question that is asked.  Some answers are technically
>accurate but many are anecdotal observations or repetition of answers that
>have been passed around for several years and which are now much different
>than the original answer.
>
>Does this help you look and think differently about your observations,
>perceptions, and experience?  Then I have obtained my goal in writing this.
>
>Best wishes all.
>
>James C. Bach
>WSDA State Apiarist
>Yakima WA
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