Agriculture Reference
In-Depth Information
European foulbrood-infected larvae are first noted because they are tan to yellowish,
turning dark brown and eventually to black. The larvae die before the cell is capped,
and the remains are easily removed by the bees, thus somewhat reducing the incidence
of further infestation.
The best defense is to have bees that are extremely hygienic who will clean out dead
larvae before the fungus matures and produces spores. This pretty much stops the in-
festation. For a brand new package on foundation the likelihood of this developing the
first season is next to zero. Next spring be on the watch for it though, and if feeding
and time don't reduce or eliminate the problem consider requeening your colony with a
strain of bees claiming to be more hygienic than the norm. There are no chemical cures
or treatments for this disease. Good management and resistant bees are the things that
work.
European Foulbrood
Yet another stress disease, the bacteria
Melissococcus pluton
is associated with spring-
time stress. Much like chalk, spores are fed to young larvae by nurse bees. Spores
emerge, compete for food, and the larva starves at a very young age. The bacteria con-
sume the larval tissue until all that's left is a twisted, brown rubbery mess, usually still
curled at the bottom of the cell. Sometimes they are stretched out lengthwise along the
side. These scales are removed by nurse bees who then come in contact with the spores.
Like chalk, spores are first encountered when bees from your colony rob an infected
colony, bees with spores drift into your colony, or you exchange equipment from an in-
fected colony.
Your first indication of an infestation is a brood pattern that appears spotty. Careful
examination shows scales—these dead larvae—in the cells. You can remove one with a
toothpick to examine and see if it matches the description above.
Consider treatment the same as for chalk. Use hygienic bees, reduce stress to a min-
imum, make sure adequate food is available, provide good ventilation, and make sure
that the colony gets as much sun as possible. Generally a good honey flow, warm weath-
er, and a healthy population of hygienic nurse bees cleans up European foulbrood. You
most likely won't see this the first season you have bees from a package, but, like chalk,
watch for it the next spring. Requeening is always a good idea if this becomes a persist-
ent problem.
