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Honey Bee Tracheal Mite

Division of Plant Industry – Apiculture
8995 East Main Street
Reynoldsburg, Ohio 43068-3399



Cause: A tiny endoparasitic mite, Acarapis woodi, (Rennie) which is not visible to the naked eye.

Identification: A positive mite diagnosis should be made in the laboratory with the aid of a microscope. The presence of the mite can be observed through the large thoracic trachea. A bees respiratory system consists of trachea and spiracles (breathing holes).

The trachea are branching tubes which lead from the spiracles to all parts of the body. Spiracles are located on the thorax and on the abdomen. Oxygen is transported directly to the cells by these tubes and carbon dioxide is eliminated in the same manner.

The appearance of an uninfested trachea is glistening white in color. Light mite infestations will cause the trachea to appear translucent. Severe infestations will show bronze or black spotted areas on the trachea. Many times adult mites and eggs are visible in the infested trachea.

The female mites measure from .004 – .007 inches long and the males, .003 – .005 inches long. The eggs are large, often exceeding the size of the adult male.

Spread: The spread of the mites can occur from:

  1. drifting of workers and drones between colonies;
  2. robbing;
  3. transferring bees;
  4. sale of bees;
  5. swarming.
The most serious of these is robbing.  Colonies heavily infested by mites become weak and subject to robbing. The colonies doing the robbing can become heavily infested.

Infestation can begin with a female mite which has mated and has left the trachea of the host bee. The mite crawls out of the trachea on a bee hair. where it waits to make contact with another bee. Once contact is made, the mite moves to the spiracle, then enters the trachea to lay 5 to 10 eggs. The mites breed and migrate all year. Mites usually die within 24 hours if removed from the bee.

Effects: Workers, queens and drones can all be invaded by the mite. This invasion of the trachea shortens the life of the bee and weakens the bee so it is unable to fly. Bees will die in the field and also can be found crawling in front of the hive. Pollination benefits and honey yields from infested colonies are reduced because of the shortened life of the worker bee.

Tracheal mites could persist in a colony for years causing little damage, but combined with other diseases, unfavorable conditions, scarcity of pollen, and/or a poor foraging season, the disease could significantly increase the mortality of colonies in the winter.

Control: Menthol crystals have shown to be effective in controlling the mites. Experiments have indicated approximately 2 oz. of the crystals killed 85% of the adult mites in only three days time. In four weeks all adults were apparently dead. The menthol is placed in packets. Remove all honey supers before any treatment. Always follow label directions.

Menthol can be obtained from most bee supply dealers.


Acorapis woodi in feeding position
(X500) photo: Baker & Slyer

Prepared by: Gordon Rudloff
State Apiarist
Ohio Department of Agriculture