About Beekeeping - The Backyard Beekeeper - page 130

For American foulbrood infestations look for scales, the dried remains of the dead larvae
in the cells. They are hard and difficult to remove. Here, they are shiny black, but some-
times they are dull black. Usually the bees can't remove them, but they try, and in the
process pick up spores, spreading them around the colony.
The Value of Early Detection
If you missed early detection, you can be fairly certain that most brood frames have sev-
eral to many infected brood, that most of the nurse bees have been contaminated, and
that some percent of the field force is contaminated also. This means when you destroy
a colony's equipment you must destroy the bees within.
Detecting early signs of AFB, or any brood disease for that matter, begins with
examining the brood very carefully. Healthy brood is glistening white. Diseased
brood—whether by AFB, EFB, chalk, or other diseases—are not white. The colors may
range from translucent to tan to brown to nearly black. Your first clue, and the key to
early detection, is the presence of larvae in their cells that are not pure, bright white.
Once an infected larva's cell is capped and the larva dies, the wax capping over the
cell changes. Rather than remaining just slightly convex, it sinks in and will usually
change color.
Some house bees with hygienic behavior traits may begin to investigate this odd cell
by opening it up at the center. Other bees with strong hygienic behavior will then re-
move the diseased larva before the bacteria have a chance to form spores.
This is where an effective integrated pest management program gets tricky. Because
of regulatory zero tolerance for AFB an infestation must be treated or destroyed. It's my
opinion that the antibiotic route is unacceptable because once applied it is a life sentence
for the equipment, the beekeeper, and the bees that live there because the equipment is
contaminated forever. However, a strong hygienic colony can tolerate a light infestation
of AFB by keeping it cleaned out. Destroying a colony like this removes those hygienic
genes from the population and leaves only bees that are susceptible to AFB.
Tracheal Mites
Tracheal mites, Acarapis woodi , are microscopic in size and cannot be directly ob-
served. These mites are considered to be universal, and unless you have known resistant
strains of bees, you should assume bees you buy have them and you will have to manage
them. Fertile female mites enter the main thoracic trachea (breathing tube) beneath