Subject: Almost Full Text of http://www.wvu.edu/~agexten/varroa.htm >>FORMULAS<<

From: Tom Smith <[email-masked]>
Date: Tue, 20 Aug 1996 15:56:08 -0400

Adam Finkelstein wrote:
> 
> In article <[email-masked]>, Allen Dick <[email-masked]> wrote:
> >In article <[email-masked]>,
> >   nickhull@ (Nick Hull) wrote:
> >>I saw the following in the news.  Does anyone know where on the net
> >this
> >>info is posted?  How about Arine's e-mail address?
> >
> >http://www.wvu.edu/~agexten/varroa.htm

I am very close to WVU and I had a hard time getting varroa.htm so I am 
posting it:
Letter to Editor, ABJ

                                        Preliminary Results of Research 

                                                Varroa Mite Control, 24 
June, 1996

Dear Editor,

We have been working with Bob Noel, a beekeeper in Cumberland, Maryland, 
since August, 1995.

In our opinion, Bob has discovered an effective and economical control 
for varroa mite (Varroa jacobsoni Oudemans (Acari: Varroidae)) and 
probably also for
tracheal mite (Acarapis woodi (Rennie) (Acari: Tarsonemidae)); we saw 
very few tracheal mites in the hives examined.

The following is a brief account of our work and preliminary findings 
during the past year.

In summer and fall of 1995, Bob fed syrups containing essential oils1 to 
his bees, specifically wintergreen oil and spearmint oil. He mixed 10 to 
20 drops (1/2 to 1
cc, respectively) of the oils to 453.6 grams (one pound) of sugar in a 
0.95 liter (1 quart) jar, and hot water was added to fill the jar. This 
syrup was then fed to the
bees at the entrance using a standard boardman feeder. He applied the 
two syrups to 14 hives as follows: spearmint oil to 5 colonies and 
wintergreen to 9 colonies
beginning in July and continuing until October. In July, 1995, several 
of the colonies displayed typical PMS (parasitic mite syndrome): they 
were suffering from mite
viruses, such as CBPV, from sacbrood which was quite heavy, and the 
brood pattern was scattered and incomplete, very similar to American 
foul brood (AFB),
however, none of the colonies had AFB. Many of the emerging workers were 
small with shriveled wings and very small abdomens. Two of the colonies 
were so
weak in July that wax moths were attacking comb and brood. Syrups were 
given ad lib and topped up daily. Bob assayed varroa mite populations by 
opening
sealed brood cells, both drone and worker, by observing emerging brood 
and by directly observing varroa mite behavior. 

Results: after using treated syrups for three weeks, Bob noticed 
improved brood patterns, healthier bees, and reduced mite populations. 
After 30 days of
treatment (we inspected the colonies in August, 1995) varroa mites were 
definitely in decline and the bees were considerably recovered from PMS. 
On 21
September, we thoroughly inspected several hives; those that were 
treated with syrups were virtually free of varroa mite, whereas 
untreated control colonies in the
area were heavily attacked by varroa mite, had typical PMS, and were 
beginning to die off.

In November 1995, Bob found that two of his bee yards (Oldtown, MD and 
Kifer, MD) which were free of varroa mites in July and August, were 
heavily infested
with varroa mites (2-3 mites per adult bee). We believe that workers 
>from  collapsing feral colonies had joined with these colonies bringing 
in enormous numbers of
varroa mites. Bob treated some colonies with apistan strips and grease 
patties (without essential oils) and others with grease patties 
containing the following: four
cups of granulated sugar, two cups of shortening and 4.8 cc's of 
wintergreen oil. This mixture was made into 8 oz patties and placed one 
per colony above the
cluster. The following spring and early summer only a trace of varroa 
mite could be found in the hives treated with the grease patties 
containing wintergreen oil;
several of the colonies treated only with apistan and standard grease 
patties died out. 

In May 1996, Bob devised the tracking strip method of varroa mite 
control: strips of 1/8 in. plexiglass, 7.5 cm by 35.5 cm (3" by 14"), 
were used as a support
for a slurry made as follows: 4 parts mineral oil mixed with 1.5 parts 
melted beeswax; this liquid was then poured into 4 oz. baby food jars to 
which 2 cc's of
patchouli oil and 2 cc's of wintergreen oil were added. Then ½ to 3 
teaspoons of the slurry were applied to the each tracking strip with 
fingers, which were placed
lengthwise just inside the front entrance of each colony. He began these 
treatments early in May. The day after strips were applied, dead varroa 
mites were found
on the tracking strips--several dead mites per colony. 

Bob's associate, Harry Mallow (a beekeeper for 30 years, former Maryland 
bee inspector, and former president of the Maryland State Beekeepers 
Association)
treated one hive (his last surviving colony at beeyard No. 2) with the 
tracking strip on 31 May, 1996 (double the dose of patchouli and 
wintergreen oils; i.e., 4 cc
of each oil in 4 ozs. of the slurry). On June 1st, both Harry and Bob 
observed several 100's of dead varroa mites at the entrance, on and 
around the strip. They
returned on June 2nd to videotape the dead mites--most had been carried 
off by ants, but several dozen dead mites still remained at the 
entrance. Amrine
inspected this colony on 6 June, 1996, and found very few live varroa 
mites on workers in the hive (two were seen on 1000's of bees examined). 
About 100
sealed drone cells were examined; several recently capped drone cells 
contained 18 to 25 highly aggitated varroa mites--they ran around the 
larva or pupa very
rapidly and ran quickly onto and over the combs. It appears that at the 
time of treatment they entered nearly capped drone cells as if they were 
"bomb shelters" to
avoid the tracking material. The older capped drone cells (with colored 
pupae and capped before the treatment) contained normal numbers of 
normally developing
varroa mites.

On June 6, 1996, Amrine inspected 12 of Bob Noel's colonies, in three 
bee yards, and collected all varroa mites that could be found. About 100 
sealed drone
cells and several worker cells were opened in each colony. Four sealed 
drone cells were found infested with varroa at his "Rick's" bee yard in 
Cumberland, MD:
two in colony number 4, treated with a tracking strip containing the 
mineral oil-beeswax slurry and 4 cc of patchouli oil in a baby food jar 
(4 oz); and one each in
colonies 2 and 3 which were treated with the same slurry containing 2 cc 
of wintergreen oil and 2 cc of patchouli oil (in 4 oz.). Varroa mites 
were not found in hive
number 1 (same treatment as hives 2 and 3). We regard these numbers as a 
trace infestation of varroa mites. (The same colonies were inspected by 
Maryland
bee inspector Dave Thomas, who found no live varroa mites on 18 May, 
1996). No deformed bees were found; there were 12 to 14 frames of brood 
in each
colony which were the best looking colonies we have seen in the last 
three years.

Inspection of the Kifer, MD bee yard resulted in finding only two sealed 
drone cells with varroa mites (one each) out of 100 drone cells examined 
(hive number 3).
This hive had been treated only with grease patty + wintergreen oil in 
November 1995, and a tracking strip (slurry made from 4 parts canola oil 
+ 1.5 parts melted
beeswax and 2 cc of patchouli oil) was added 30 May 1996. The colonies 
had two or three mites per adult bee in November, 1995.

Inspection of the Oldtown, MD, bee yard resulted in finding 3 sealed 
drone cells containing varroa mites out of 100 cells examined in each of 
two colonies. These
had been treated with grease patties containing wintergreen oil in 
November 1995, and had received no other treatment. In November, the 
colonies had two or
three varroa mites per adult bee.

Summary of Treatments:

1). Syrup: 10-20 drops of wintergreen or spearmint to one pound (453.6 
grams)of sugar in a quart jar (0.95 liter); hot water added to fill jar.

2). Grease patties: made with four cups of granulated sugar, two cups of 
shortening and 4.8 cc's of wintergreen oil. 

3). Tracking strips: strips of 1/8 in. plexiglass, 7.5 cm by 35.5 cm (3" 
by 14"), were used as a base for holding a treated slurry made as 
follows: 4 parts mineral
oil mixed with 1.5 parts melted beeswax; this liquid was then poured 
into 4 oz. baby food jars to which 2 cc's of patchouli oil and 2 cc's of 
wintergreen oil were
added. Then ½ to 3 teaspoons of the cooled slurry were applied to the 
tracking strip which was placed lengthwise just inside the front 
entrance of each colony.
These treatments were repeated after 5 days: the old slurry, dead mites 
and dead deformed bees were scraped off and new slurry added. 

CONCLUSIONS:

Bob Noel's experiments from July 1995 to the present have demonstrated 
that essential oils in sugar syrup, grease patties and tracking strips 
are able to greatly
reduce populations of varroa mites in bee colonies. 1) Spearmint oil at 
the rate of ½ to 1 cc per quart of syrup (1# of sugar) had the best 
results when fed in July
through October; wintergreen oil was less effective, but still highly 
effective, in these experiments. 2) Grease patties containing 4.8 cc's 
of wintergreen oil were very
effective from November until April in reducing and nearly eliminating 
varroa mites in heavily infested colonies treated in November. 3) 
Tracking strips containing
2cc of patchouli oil and 2 cc of wintergreen oil (or 4 cc of patchouli 
oil) are very effective in controlling varroa mites during spring build 
up. 4) In all cases of
successful treatments, the essential oils were delivered to the brood 
nest of the treated colonies. The importance of this last observation 
can not be
overemphasized. Two experiments of ours support the importance of this 
point.

First, Harry Mallow began sugar syrup treatment of 16 colonies at his 
bee yard No. 1 in September, 1995. He treated 8 colonies with syrup and 
essential oils only
(4 with 15 drops of wintergreen oil per pound of sugar, and 4 with 15 
drops of spearmint oil); the cans were placed at the top of the colonies 
(in contrast to
boardman feeders placed at the entrance by Bob Noel). [Nurse bees and 
foragers collect nectar from a boardman feeder and the syrup and 
essential oils go to the
brood; feeders at the top of a hive do not usually deliver syrups or 
food directly to the brood nest.] Four more of his colonies were given 
wintergreen syrup +
apistan strips and the last four colonies were given untreated syrup as 
controls. Only the four colonies with wintergreen syrup + apistan 
survived. These colonies
were treated too late and the syrup was fed in the wrong location: at 
the top of the colony instead of the entrance.

Second, Harry also treated one colony located in his beeyard No. 3 in 
April of 1996 with canola oil + wintergreen oil (4 cc of wintergreen in 
4 ozs. of canola); a
folded paper towel with canola + wintergreen was laid on a queen 
excluder above the cluster. He got a good kill of varroa mites (many 
were found dead on the
bottom board). He continued this treatment for several weeks. We 
inspected the colony on 6 June, 1996: a paper towel with canola oil was 
on top of a queen
excluder at the top of the colony (1 and ½ story); it had not been 
touched by the bees (in contrast, the original paper towel was shredded 
by the bees in April).
[After April, the bees have little reason to go to the upper part of the 
hive and will not be affected by treatments placed there.] About 100 
sealed brood cells
(mostly drone) were examined in this colony; about 1/4 of the drone 
cells contained normally developing varroa mites. Obviously, this 
treatment, though effective in
April when the cluster was near the top of the upper super, was no 
longer working. Thus the presence of the essential oils in the top of 
the hive was insufficient to
cause reduction of varroa mite. This probably explains some of the 
negative reports we have read or heard from other researchers using 
essential oils--they
apparently did not deliver the oils to the brood nest in a way that 
nurse bees and foraging bees would be treated; thus the tracking board 
at the entrance is highly
effective, the syrup fed by boardman feeder is highly effective, and 
treated grease patties above the fall and winter cluster proved highly 
effective. The treatments
must be delivered to the brood nest--in such a way that nurse bees and 
foraging bees are treated.

Proposed mechanisms of action:

Our observations of Bob Noel's experiments in 1995 and 1996 indicate the 
following mechanisms are probably at work in controlling varroa mites:

1) Direct toxicity: The grease patties and tracking strips indicate that 
the essential oils are able to kill varroa mites by direct contact, 
within 24 hours or less.
Honey bees are not harmed by these oils at the rates used; honey has not 
been found to be contaminated by any of the treatments used to date 
(taste test). The
evidence to date is strong enough to prove that this is definitely a 
mechanism of varroa mite control; however, no case has been observed 
where direct toxicity has
totally elliminated the mites. For now, it can only be regarded as a 
partial control and effective only at time of treatment and for several 
days following. 

2) Sensory disruption: it seems that the essential oils from grease 
patties and tracking strips are able to mask the normal chemosensory 
receptors on the tarsi and
mouthparts of varroa mites, disrupting the mite's ability to function 
normally. As a result, they are not able to properly invade larval cells 
about to be capped, nor
do they seem to be able to properly insert themselves under the 
sternites of worker bees and feed on bee hemolymph. They may not be able 
to recognize adults
and mature larvae of honey bees because of the presence of the grease + 
oils on the mites' cuticle and sensory receptors. This mechanism is 
hypothetical and is
supported indirectly by observations of behavior of varroa mites in 
treated colonies by Bob Noel, Harry Mallow and us.

3) Reproductive disruption: it is apparent that varroa mites in all 
three methods of treatments are not able to reproduce normally. 
Examination of cells at or near
the time of emergence of bees and mites from mite-infested cells in 
treated colonies show that few newly developed females are found; many 
cells have been found
containing dead immature mites and single females that never reproduced 
(so-called nonreproducing or sterile females). We conclude that the 
essential oils are able
to disrupt the reproductive mechanism of the varroa mite. 

It is known that under natural, untreated conditions, the female varroa 
mite, after feeding on a larva in a sealed cell for 1-2 days, normally 
becomes "gravid"--she
appears swollen and the cuticular membrane between the sternal and 
genital plates becomes stretched and evident as white borders around the 
plates. The
so-called "eggs" deposited by the female are in reality immature mites 
that are ready to emerge as protonymphs, the embryonic and larval stages 
having been
completed within the chorion inside the body of the female. Thus, the 
female is converting the blood of the bee larva and/or pupa into 
nutrients for each developing
immature mite. This part of the varroa's development is viewed by us as 
its weakest point, the so-called "Achilles' Heel" of the varroa mite, 
and appears to be the
major target of action of the essential oils. The oils may be disrupting 
enzyme systems used to convert bee blood nutrients into nutrients for 
the developing
immature mites and so the females are not able to produce "eggs". Also, 
after hatching, very few of the mites in treated colonies were able to 
complete
development by the time the bee emerged from the cell. 

These mechanisms help explain observations given to us by several 
beekeepers where honey bee colonies were located in regions with 
blooming plants rich with essential oils, such as mints,

>>>> sorry, tha's all I got.   tom