OARDC/The Ohio State University

Horticulture and Crop Science

1680 Madison Ave., Wooster, OH 44691

Controlling Tracheal Mites in the Bee Hive

HYG-2164-97

E-mail Tew.1@osu.edu

Tracheal mites (Acarapis woodi) were first reported in the United States from Texas in 1984. By 1992, severe colony losses due to tracheal mites were recorded throughout Ohio. Tracheal mites are microscopic parasites that live in the breathing tubes of adult honey bees where they feed on bee blood. Suffering colonies have dwindling populations, do not cluster well, and often die in the winter, frequently leaving behind large amounts of honey. Infested adults may act irritated or disoriented. Weak adults may be found crawling aimlessly near the entrance of the hive. Unfortunately, tracheal mites cannot be positively identified without dissecting the bees under a microscope. Two materials, vegetable oil patties and menthol, are useful in suppressing tracheal mite populations. Eradicating mite populations is not practical. Since any material only suppresses mite populations temporarily, beekeepers should be prepared to contend with tracheal mite infestations indefinitely.

Vegetable Shortening Patties

Precautions: As a matter of principle, don't have patties, or any other medications on during a nectar flow. Always follow label instructions.

Product: Vegetable Shortening (eg. Crisco™)

Ratio: One part vegetable shortening to 2 parts white granulated sugar. Patty size should be about one-half pound (size of a hamburger).

Exposure Time: Continuous (except during nectar flow). Replace as often as needed. Most effective during spring and autumn.

Location within the colony: On broodnest top bars.

Comments and Suggestions:

1. Vegetable shortening appears to disrupt the life cycle of the tracheal mite, thus suppressing mite populations.
2. Vegetable shortening patties are considered to be more effective in controlling mites in Ohio than menthol. However, menthol is still useful.
3. Vegetable patties with terramycin is useful in controlling American Foulbrood. Refer to the factsheet on American Foulbrood for specific recommendations.

Menthol

Menthol is available in bulk quantities or in 1.8-ounce (50 grams) packets from most major bee suppliers. Treat only over-wintered colonies having no surplus honey intended for human consumption. Colonies should be treated in the fall or early spring when daytime temperatures are expect to be above 60°F but not over 95°F. Treatment must end one month before the first nectar flow to avoid contaminating marketable honey. Use one menthol pact per hive, on top bars in temperatures up to 80°F. Above 80°F, place the packet on the bottom board. Treat for 14 to 28 days with an entrance-reducer on the hive. Replace the menthol as needed during the treatment period.

Precautions: Treatments should not be in colony 4 weeks prior to honey flow. Allow vapors a few minutes to dissipate before working a treated colony. When stored, menthol crystals should be tightly sealed and refrigerated.

Product: Pure Menthol Crystals

Treatment: 1.8 oz (50 grams) packet of menthol crystals in a porous bag, such as a folded paper towel.

Rate: One 1.8 oz packet per average 2-story colony.

Number of Colonies per treatment: One (average 2-story colony).

Location within Colony: Above 8O°F, place crystals on bottom board, Below 8O°F, place crystals on top of frames in top supers.

Treatment Time: Spring preferably or autumn secondly

Treatment Duration: 14-28 days with entrance reduced, replace crystals as needed.

Comments and Suggestions: Menthol vaporization is temperature dependant. At temperatures above 7O°F, vaporization proceeds quickly; below 7O°F, vaporization proceeds more slowly. In essence, menthol treatments could stay on colonies anytime the temperature is high enough and there is no nectar flow in progress; however, this practice may be cost and labor prohibitive.