| |
|
|
The parasitic mite Acarapis woodi Hirst is not visible with the naked eye; microscopic examination is necessary as they vary in size between only 125 and 174 microns (Delfinado-Baker and Baker 1982). They are basically oval in shape and translucent-white in colour. The mite infests the breathing tubes or tracheae and the air sacs of honeybees, often in large numbers, where they pierce the trachea walls to feed on the bee haemolymph. |
| |
|
|
The life cycle of the tracheal mite, Acarapis woodi is spent entirely on adult bees; mites do not infest the brood but infect young adult bees upon or shortly after emergence.
Female mites enter the first thoracic spiracle of the young honeybee and lay 5-7 eggs. Eggs hatch in 3-4 days. The six-legged larva develops through a nymphal stage to the adult male in 11-12 days or to an adult female mite in 14-15 days (Morgenthaler, 1931).
Mating occurs within the trachea where the mites develop. Gravid female mites then leave the bee via the spiracle and attach themselves at the tips of the bee’s body hairs. When another bee comes into contact with the original host, they transfer host and infest again through the spiracles. |
Tracheal mites are as mobile as the bees carrying them
and they move within and between apiaries due on foraging
and drifting bees and swarms; however movement of honeybee
colonies by beekeepers is the greatest factor in the
spread of this parasite.
Only young adult bees under 4 days old are susceptible
to infection (Gary et al. 1989); the physiological
state of older bees seems to be a prohibitive factor
in tracheal
mite infestation. Mites transfer readily from one bee
to another and are attracted by wing vibration to the
thoracic spiracles just in the region of the wing roots
of the bee (Sachs 1952).
A common symptom of colonies heavily infested with tracheal
mite is the occurrence of adult bees crawling on the
ground or on grass around hive entrances. This may be
symptomatic of other bacterial or viral diseases the
effects of which may be enhanced by the additional stress
from tracheal mite infestation. See Miscellaneous Disease
section also.
| Disease Detection
Methods |
|
|
| |
|
To check for infection: Adult bees are decapitated and the prothoracic collar removed with a scalpel. The thoracic tracheae can then be inspected. Infested honeybee tracheae when stained show brown or black scabs or may be entirely black depending on the infestation level. In comparison, non-infested healthy tracheae appear transparent and clear-amber (Delfinado-Baker 1984). |
| Control of
Tracheal Mites |
|
|
| |
Races of bee more resistant to tracheal mite should
be used where possible. Buckfast bees are known to be
highly resistant to this mite while New Zealand strains
are very susceptible to attack.
Selective bee breeding then is the first measure that
beekeepers should employ to counteract this pest.
Menthol crystals have been used with considerable success
in North America although relatively high environmental
temperatures are required to sublime the crystals and
the effects are variable.
The Vita product APIGUARD® is especially formulated
for control of varroa and tracheal mites. Good control
levels of tracheal mite have been observed with use of
Apiguard in several countries.
See APIGUARD® in our product section or click here...
