Menthol-Canola Mix for Treating Tracheal Mites: Results of Research Conducted from Fall 1996 to April 1997

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Jim Amrine, Terry Stasny, & Robert Skidmore
West Virginia University
Division of Plant and Soil Sciences,
P. O. Box 6108, West Virginia University
Morgantown, WV 26505-6108 USA
Telephone: 304-293-6023
Fax: 304-293-2960
E-mail: jamrine@wvnvm.wvnet.edu

 

1): Measure and mix components:

Place two standard packs of menthol crystals (3.4 ozs. or 100 grams) in an 8 oz. (118.3 cc) measuring cup, then add canola oil to fill. Microwave for 4 mins. at 50% power. Check to see that all crystals dissolved--if not, microwave for an additional minute at 50% power. Must be used while warm otherwise crystals will reform.

2): Add to paper towels:

Remove 30 paper towels from one roll; fold in half and stack. Put stack of paper towels into a large zip-lock bag and add 1 cup of warm menthol-canola.

Zip the bag shut then squeeze the towels in the bag until all towels are evenly saturated. If one end of towels are somewhat dry, turn the bag sideways putting dry end down--in about 10 minutes, all will be evenly saturated.

Thus, one cup of menthol-canola mix will treat 30 paper towels--using 2 towels per colony, this will treat 15 colonies.

Towels can be stored at room temperature indefinitely if the bag is zipped closed.

3): Add to colonies:

Do not add to colonies while a honey flow is on. Place one paper towel over the top bars of each brood chamber. Best time to treat is September. (Tracheal mites are usually not a problem from May to September, so no menthol needs to be used until the time that mites begin to build up in late August or September). Colonies can be treated anytime during the winter when temperatures rise above about 45 F. We recommend this treatment whenever tracheal mites are found; additional treatments can be made in December, January and February. The bees will chew up the paper towels and discard them at the entrance in 3-4 days (or longer in winter). This mix caused no harm to our bees but definitely reduced or eliminated the tracheal mites.

Don Jackson's Shop Towel technique: A very similar technique was published in the February issue of the American Bee Journal by Don Jackson (Jackson, Don. 1997. Tracheal mites, menthol, and shop towels. Amer. Bee J. 137(2):138-139). He used a 50-50 mix of canola and menthol, heated on a stove, and then cut rolls of shop towels in half and dipped them into the pan to saturate with the mix.

 

Additional Research:

We intend to find the optimum amount of menthol needed to obtain control--maybe of this amount could be used--maybe more should be used. We also intend to observe the effects of this mix on varroa mites.

4): Calculation of costs (29 April 1997):

One cup of mix contains 100 grams of menthol = 100/453.6 = 0.22 lbs or 3.4 ozs.

One lb of menthol costs:
Lorann Oils: $36.30 per lb. (bucket of crystals)
Dadant: $24.82 per lb. (12, 50 gram packs for $31.50)
W. T. Kelley: $23.68 per lb. (10, 50 gram packs for $25.00)
Mann Lake: $19.85 per lb.

Menthol for one cup of treatment costs:
Lorann 0.22 * 36.30 = $7.99
Dadant 0.22 * 24.82 = $5.46
W. T. Kelley 0.22 * 23.68 = $5.21
Mann Lake 0.22 * 19.85 =$4.37

1 cup or 8 ozs of canola cost (47 oz bottle) 8/47 * $2.20 = $0.37

Total cost for materials (not counting labor):
Lorann: 7.99 + .37 = $8.36 for 15 colonies = $0.56 per colony
Dadant: 5.46 + .37 = $5.83 for 15 colonies = $0.39 per colony
Kelley: 5.21 + .37 = $5.58 for 15 colonies or $0.372 per colony,
Mann Lake: 4.37 = .37 = $4.74 for 15 colonies = $0.32 per colony

Costs using 50 gram packets for standard menthol fumigation:
Lorann Oils: $36.30 per lb. (36.30 / (453.6/50)) = $4.10 per colony
(you provide the perforated packets at $.10 each)
Dadant: $24.82 per lb. (12, 50 gram packs for $31.50) = $2.62 per colony
W. T. Kelley: $23.68 per lb. (10, 50 gram packs for $25.00) = $2.50 per colony
Mann Lake: $19.85 per lb. / (453.6/50) = $2.29 per colony
(you provide the perforated packets at $.10 each)

5): Storage experiment:

We conducted an experiment for two year storage of menthol packets (from Man Lake) sealed in a heavy plastic bag and kept in a refrigerator at 35 degrees F.

After storage:

 Packet  Weight of Packet (grams)*
 1  53.71
 2  51.00
 3  52.23
 4  53.18
 5  51.88
   Average Value = 52.40 g (se = 1.07)
   Avg. Bucket Wt.= 2.34 g
   Avg. g menthol / packet = 50.05

Conclusion: very little menthol was lost.

 

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