METHODS OF APPLICATION AND TEST RESULTS.

Dr. Pedro P. Rodriguez
Dr. Veterinary Medicine, U. P. 1962
Retired GS-13 United States Department of Agriculture
Retired United States Army Colonel

Abstract

Parasitic bee mites represent a formidable threat to susceptible honey bees
of the Apis mellifera species. Destruction of most feral colonies and a high
percent of domestic bees has alarmed the scientific community worldwide
giving rise to teams of investigators studying various forms of treatment to
combat them. Because of the bees' vulnerability and potential contamination
of honey, the number of substances that can be utilized for that purpose are
few and restricted by law. Mites have developed resistance to fluvalinate
increasing the need for alternative methods of treatment. Food grade mineral
oil, FGMO, is assayed in search of a bee friendly, environmentally friendly
and cost effective method of treatment for bee mites.

Key words

Varroa jacobsoni Oud, food grade mineral oil (FGMO), Apis mellifera, Apis cerana,
parasitic bee mites, fluvalinate.

Introduction

Although mites have been known as parasites of honey bees for nearly a hundred
years, their notoriety is recent in the western hemisphere. In Asia, their
original habitat, parasite and host have achieved an optimum state of coexistence.
Many researchers agree that one bee species, Apis cerana, has developed its own
form of protection against the mites, through individual and colony hygenic
habits. In this species, bees groom themselves to remove adult mites and discard
infested bee larvae (Peng et al, 1987) thus keeping the mite population low. Spivak
and Gilliam, 1998, give high praise to the value of hygenic behavior in mite and
disease control citing an abundance of literature on this subject (33 authors).
Other contributing factors found in this bee species are: mites preference for drone
larvae (Koeninger, 1981); temperature and climate (Eischen, 1987). On the contrary,
it is generally accepted that European bee species lack some of the factors observed
in A. cerana species (Faucon, 1991). Spivak and Gray, 1998, reported that in the
United States hygenic behavior is estimated to be found in only about 10% of managed
colonies, fact that contributes to the vulnerability of managed bees.

According to general opinion, many factors have combined in favor of the mites.
In Europe, generalized skepticism by beekeepers about the mites' harmful potential
contributed to spread of the mites from middle European countries to the southern tip
of the Iberian Peninsula with an amazing rate of dissemination. In the United States,
Varroa made its initial appearance in the state of Florida in 1987 and has spread
practically throughout the entire continent within a decade destroying in its wake
nearly 100% of the feral bee population and a very high per cent of managed bees
(Sammataro, 1997). Several researchers have indicated that misuse, misinterpretation
of instructions about Apistan and lack of knowledge about the genetics of bee mites has
led to development of resistant generations of mites in the United States and abroad.
Resistance to fluvalinate has been documented in Italy (Faucon et al, 1995; Lodesani et al,
1995; Milani, 1995). In the United States, resistance to fluvalinate has been verified in
the states of Florida and South Dakota (Eischen, 1998) and rumored identified in as many as
six states.

Material and Methods

A. Materials

	1. Standard Langstroth type hive body chambers and medium size supers. 2. Penreco Food grade white mineral oil. 3. 14 1/2" x 18" waxed paper or freezer paper. 4. 1 1/2" x 10" waxed paper strips. 5. Calibrated eye dropper. 6. One pint bottle dispenser provided with a wick and mounted on a Luan wood stand. 7. Portable propane insect fogger. 8. Tobacco leaves and stems. 9. Penreco Food Grade White Mineral oil/sugar emulsion patties. 10. Bee colonies of similar strength.

B. Methods of Application.

Several methods of application of food grade mineral oil have been tested in
a period of time spanning from 13 April 1996 to 21 November 1998.

1. Laboratory.

Fiftyfive mites collected from eleven colonies in a wide mouth glass jar and driven
a short distance for testing. (Mites were removed from the jar by allowing them to
crawl on tooth picks).

	a. 10 mites placed on a glass slide and gently dabbed with a Q-tip soaked with FGMO. b. 10 mites placed on a top bar previously smeared with FGMO. c. 10 mites placed on a sheet of waxed paper smeared with FGMO. d. 10 mites placed on a "sticky trap" prepared with waxed paper smeared with FGMO. e. 10 mites placed in another jar smeared with FGMO. f. 5 remaining mites allowed to stay in original jar. Top edge of jar was smeared with (OFF) insect repellent to keep mites from escaping.

2. Field Tests.

	a. sheets of waxed paper smeared with FGMO placed on the bottom boards. b. strips of waxed paper smeared with FGMO inserted between frames. c. 2.5 cc FGMO placed on top bars in a continuous bead. (previously reported on the internet). d. FGMO in one pint bottle dispenser with stand placed on top bars. e. portable propane insect fogger.

1996-1997 Trials

(1). Twenty five Italian bee colonies (twenty test colonies and five control
colonies) of similar characteristics and size. Bees were distributed in three
sites at least 16 miles apart. Initial mite counts were performed on each
colony by uncapping 100 capped cells within a 3" x 4" inch homogeneous area
of brood combs.

1998 Trials

(2) Five test sites were established in cooperation with area beekeepers.
Colonies utilized were of similar characteristics and size, forty colonies
being last year's bees. All colonies consisted of a full body brood chamber
and one medium sized super (1) and additional supers added as needed for
stored honey. All colonies were numbered and control colonies were selected
at random at each site. Initial mite counts were performed by uncapping 100
capped cells within a 3" x 4" inch homogeneous area. Test colonies were treated
every two weeks with FGMO applied with a Burgess brand portable propane insect
fogger. Beginning on 5 July 1998, all colonies were smoked with tobacco smoke
and mites were collected on "sticky traps" on the bottom boards.

(1) Several swarms of unknown origin collected during the Spring and Summer of
1998 were added to project at site # 5 and treated with FGMO.

Distribution of test colonies:

	Site No. 1.	Ten test colonies; three control colonies. The number of test colonies at this site diminished as site owner joined the colonies that became weak.
	Site No. 2.	Four test colonies; one control colony.
	Site No. 3.	Three test colonies; one control colony.
	Site No. 4.	Six test colonies; three control colonies.
	Site No. 5.	Two colonies owned by site owner. Seven additional colonies developed from swarms. Colonies were divided into 7 test colonies and two control colonies.

Results

A. In vitro tests.

	a. mites died within one minute. b. mites died within two minutes. c. mites died within two minutes. d. mites died within two minutes. e. mites died within two minutes. f. mites died on the 4th day.

B. Field tests.
Penreco White Food Grade Mineral Oil (FGMO).

a. 27 April 1996: Waxed paper sheets 14 1/2 wide by 18 inches long coated
with mineral oil (one tablespoon per sheet) were placed on bottom boards of twenty
colonies. Five colonies randomly selected were left untreated for control purposes.
Inspection of waxed papers on bottom boards revealed a varied number of mites
(19 to 108). The number of mites found on these sheets is not accurate since the
bees chewed and removed part of the paper before mites were counted.

	Capped cell mite count: 36% in treated colonies. Capped cell mite count: 54% in control colonies.

b. 11 May 1996: Waxed paper sheets coated with FGMO (one tablespoon per
sheet) placed on top bars between brood chambers and honey supers. (On 25 May 1996,
waxed paper sheets were replaced with freezer paper obtaining similar results).

	Dead mites harvested on sticky trap 28%. Capped cell mite count: 30%.

c. 6 June 1996 - 4 January 1997. Twentythree Italian race bees in Langstroth
type hives (one brood chamber and one medium size super) distributed in three sites.
Colonies were labeled with continuous numbers 1-23, (#'s 10, 13, 15, 18, 20, 23
randomly selected as controls (2)). Waxed paper strips coated with FGMO inserted
between frames of brood chamber revealed the following findings. Strips were replaced
every two weeks.

	((2) All colonies utilized as controls died.) Capped cell mite counts at two week intervals. 13%, 9%, 8%, 6%, 5%, 4%, 3,%, 2%, 2%, 0%(3), 0%(3), 0%(3) ( (3) There was no brood present in the last three colonies listed.)

In the Spring of 1997, the form of application of FGMO was changed from waxed paper
strips to a continuous bead of oil spread on the top surface of the top bars. This
form of treatment was applied to 23 colonies surviving from the precious year and some
colonies formed from swarms strengthened with package bees and distributed in 3 sites.
At first, the amount of oil was measured and applied with a graduated eye dropper, arriving
at 2.5 cc of oil as a safe quantity. Later, it was applied with a bottle similar to a
honey bear with a spout with an opening measuring 1/16" in diameter. During the course
of application, it was determined that it was not necessary to spread the oil, the bees
spread it as soon as they walk on it. The following results were observed. Of the 20
colonies treated with FGMO, one absconded and two were small and weak and died due to
pilferage. Three colonies used as controls died. Capped cells examined revealed mites in
both drone and worker bee cells. Mite counts varied from 54% to 4% during this test
period.

On Sunday, August 24, 1997, a new method of application of FGMO was initiated on 24 colonies (remaining colonies from previous tests and collected swarms). In this test, oil was applied by means of pint bottle dispensers. See diagram. Although promising, this form of application was discontinued because the bees did not come in contact with enough oil for it to be effective. There was not enough time left to make modifications needed since it was started late in the season.

f. Application of FGMO with the Burgess Portable Propane Insect Fogger.

Site No. 1.Ten test colonies and three control colonies. The number of colonies at this site diminished as participant joined the colonies that became weak. Significantly, mite counts nearly doubled in the colonies that were joined together. Conversely, in colonies that remained intact, mite counts diminished with treatment or showed very slight increase.

1). 72 mites during first count to 134 mites counted after joined together. 2). 40 mites during first count to 150 and 259 after joined together. 3). 92 mites during first count to 206 and 580 mites in subsequent counts. 4). 27 initial mites counted followed by 60 mites and 35 mites in subsequent counts. 5). 67 initial mites counted followed by 60 mites and 85 mites in subsequent counts. 6). 23 initial mites counted followed by 64 mites and 47 mites in subsequent counts. 7). One of the control colonies died and one colony absconded.

Site No. 2: Four test colonies and one control colony. (Colonies had two supers). Although two of the test colonies developed AFB during the course of the test, results were fairly consistent with results obtained at sites 3, 4, and 5.

1). 3 initial mites counted followed by 12 mites and 17 mites in subsequent counts. 2). 4 initial mites counted followed by 9 mites and 13 mites in subsequent counts. 3). 2 initial mites counted followed by 4 mites and 23 mites in subsequent counts. 4). 5 initial mites counted followed by 9 mites and 56 mites in subsequent counts. 5). Control colony: 2 initial mites counted followed by 21 mites, 39 mites and 1004 mites when submitted by the owner to an Apistan knock-down test at the end of the test period.

Site No. 3: Three test colonies and one control colony.

1). 3 initial mites counted followed by 14 mites and 17 mites on subsequent counts. 2). 5 initial mites counted followed by 7 mites and 12 mites on subsequent counts. 3). 6 initial mites counted followed by 13 mites and 3 mites on subsequent counts. 4). Control colony: 8 initial mites counted followed by 30 mites and 195 on subsequent counts. This colony died in September.

Site No. 4: Six test colonies and 3 control colonies.

1). 3 initial mites counted followed by 19 mites and 24 mites on subsequent counts. 2). 0 initial mites counted followed by 3 mites and 4 mites on subsequent counts. 3). 2 initial mites counted followed by 26 mites and 23 mites on subsequent counts. 4). Control colony: 3 initial mites counted followed by 35 and 109 mites.(4) 5). 2 initial mites counted followed by 10 mites and 22 mites on subsequent counts. 6). 11 initial mites counted followed by 16 mites and 27 mites on subsequent counts. 7). Control colony: 4 initial mites counted followed by 19 mites and 90 mites. (4) 8). 2 initial mites counted followed by 3 mites and 22 mites on subsequent counts. 9) 6 initial mites counted followed by 25 mites and 108 mites. (4)

(4) All three control colonies developed chalk brood disease and died when robbed by their neighbors.

Site No. 5: Two original colonies and seven additional colonies developed from swarms. Tests at this site began in mid summer when participant joined test program with two colonies, one test and one control. All but one of the swarm colonies responded well to FGMO treatments.

	1). 11 mites initial count followed by 13 mites and 13 mites on subsequent counts. 2). Control: 33 initial mites counted followed by 57 and 100 mites subsequent counts. (5) 3). 7 initial counted followed by 14 on subsequent count. 4). 33 initial mites counted followed by 57 on subsequent count. 5). 24 initial mite count followed by 73 on subsequent count. 6). Weak, re-queened, absconded. 7). Queenless, re-queened, absconded. 8). Died. 9). Absconded
	(5) Control colony became weak, diseased, robbed and died.

On 21 November 1998, 21 colonies were treated with 40% FGMO/sugar emulsion
patties at sites 3, 4 and 5 in an effort to assay the feasibility of continued treatment
with FGMO during the winter without recurring to chemical treatments. Efficacy of this
form of treatment will be assayed next Spring and results made available in a follow
up report.

Conclusions

These tests and those of other investigators indicate that oil may be an efficient
alternative form of treatment for bee mites. The body of bee mites is flat thus
having a high ratio of surface volume (factor also used by Italian researchers) of
bee mites. Also, a study by British researchers indicate that female mites control
gaseous exchange through adjustment of components of their respiratory system.
These characteristics together with the bee/mite body size differential ratio make
bee mites vulnerable to treatment with oils without harming the bees. Applied
with the Burgess Portable Propane Insect Fogger, mineral oil is delivered in
microscopic particles averaging 15 microns in diameter dispersing the particles
through the entire hive in fog form.

The microscopic size of the particles is believed to play a very important role in the
use of FGMO as an acaricide. In this form, the oil penetrates the respiratory
system of mites, blocking it and causing death by suffocation. Most importantly, it
appears that mineral oil applied in this form is also effective for the treatment of
tracheal mites since the oil penetrates the respiratory system of the bees,
exposing the mites to the effect of the oil as it does to Varroa mites. Continued
dissection of bee tracheas revealed total absence of tracheal mites in test
colonies. These findings are consistent with those of a beekeeper in the Canary
Islands (Spain) utilizing mineral oil for treatment of tracheal mites. The beekeeper
wrote indicating great degree of effectiveness of FGMO for that purpose.

Initial phases of tests with mineral oil proved labor intensive, reducing the
allure of mineral oil as an alternative treatment. However, when applied in
fog form the procedure becomes fast, easy and economic requiring five
seconds per hive and less than one gallon of oil for the entire year. The
fogger is not a complex machine. It is easy to operate by bee yard workers,
facilitating its use by individual and commercial beekeepers. Thus, achieving
one of the goals of the last test period, to evaluate a cost effective method of
application of mineral oil as an acaricide.

In large size colonies that require larger amounts of oil fog, the bees may
become agitated but never aggressive contrary to initial reports across the
nation indicating that the use of FGMO aroused aggressiveness. Mineral
oil applied in this form does not seem to have deleterious effects on the
hive population including queens, larvae and adults. Brood patterns are full
and uniform and no signs of larval mortality were observed. Queens continued
to lay unimpeded until late fall when last checked.

Test results indicate that at $4.50 per gallon and $65.00 for a fogger, mineral
oil with its benign characteristics can be a reliable, environment friendly and
cost effective alternative treatment for bee mites especially with increasing
mite resistance to known chemical pesticides. FGMO is far more effective
than what these tests reveal if judged by the number of mites remaining after
treatments since treated colonies continue to be subject to infestation from
neighboring control colonies. Also, FGMO would be more effective if it were to
be applied in the form of fog combined with a continuous FGMO source such
as FGMO patties or FGMO dispensers. This phase of combined forms of
application is planned to begin next Spring.

References

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Biologia de las poblaciones de Varroa jacobsoni. Resumenes del XXVIII
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Varroa Control Problems: More Answers from Florida . ABJ 137 (4): 267
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