First detected in the United States in 1984 the Tracheal mite has caused the loss of tens of thousands of colonies and millions of dollars. The tracheal mite will infest the tracheal system of the adult honey bee, they prefer adult bees less than four days old. Levels seem to be at the highest during the winter and spring. Once they are on the bee, the mites are attracted to the carbon dioxide exhaled and enter the spiracles located on the thorax, which lead to the tracheal system. They will puncture the wall of the trachea and suck the blood of the bee. Once in the tracheal system the mites live, breed and la eggs. The adult and the eggs plug the tubes of the trachea, which impairs oxygen intact of the bee. Since they puncture the trachea in order to feed, they will spread secondary diseases and pathogens. The bee dies from the disruption to respiration damage to the trachea, and from the loss of blood. Once over 30 percent of the population are infected with tracheal mites, honey production may be reduced. The likelihood of winter survival decreases with increasing infestation of the mite. Mites are transmitted from bee to bee within a colony by robbing or drifting bees.
Infested bees will be seen leaving the colony and crawling on the grass just outside the hive. They will crawl up the blades of grass or the hive, fall back down and try again. The wings will be disjointed and the bees will be unable to fly. If you are unsure about a tracheal mite infestation, send sample bees in alcohol to your local county extension agent for verification.
One method of preventing tracheal mites is an oil extender patty. It consists of two parts sugar to one part vegetable shortening. Make a small patty about four inches in diameter. Sandwich it between was paper. Cut the wax paper around the edges so the bees have access to the patty. Place the patty on top of the frames in the center within the hive body. The bees will be attracted to the sugar and get oil on their body. The oil makes it difficult for the mites to identify suitable bee hosts. The oil patties will not contaminate the honey supply so they can be used for prolonged periods.
There is one other method for controlling tracheal mite infestations. Menthol can be used and is available in most bee supply stores. The temperature must be above 60F in order for the menthol to work. The bees breathe the vapor, which dehydrates the mites. Menthol must be removed during a nectar flow so that the honey is not contaminated.