Lesson Two

A good beekeeper is one who can recognize bee diseases. An objective of this lesson and the next lesson is to help you in the identification of diseases of the honey bee. However, adequate understanding of diseases takes actual field experience. We would suggest that when you have completed the course work, you visit with the state or county bee inspector (if you have one) and ask if you might tag along on an inspection round so that you may see these diseases up close and personal.

Every beekeeper should be able to identify diseases they may encounter in the bee hive. It is important to identify the disease and take corrective action to combat it. We will examine the major bee diseases--look at examples of each and discuss treatment if there is one for the disease.

American foulbrood is wide spread and many beekeepers will encounter it on occasion. Many of our bee laws were enacted to combat the spread of American Foulbrood and resulted in states inspecting hives of bees. The laws vary from state to state but some are very strict. Some state restrict the importation of hives of bees on comb because of the threat of American Foulbrood.

Historically, American foulbrood was identified in bee books from the late 1800's in both the United States and England. However, according to Honey Bee Pests, Predators, and Diseases edited by Roger A. Morse and Richard Nowogrodzki, it wasn't until 1907 that it was demonstrated conclusively that B. larvae was the cause of American Foulbrood. Various treatments were attempted. However, it was recognized that any steps to eliminate the disease must be based on breaking the life cycle of the causative agent (Bacillus larvae). The disease is spread by careless beekeepers. Thus, we will find most state inspection programs requiring the burning of hives and bees. In states with more liberal laws, bee inspectors still feel that burning frames of comb, and the bees themselves is the best approach to the disease. Bees with a light infection of American Foulbrood can be treated with tM25 but this is a short term treatment and must be continued to avoid a reoccurring outbreak.

Young larva ingest the bacterial spores when fed by nurse bees. The spores then germinate and begin to grow rapidly. Death to the larva usually occurs as the pupae stage is reached. Larva that die turn a coffee brown and begin to melt down into a gooey mass. Housecleaning bees then try to remove the dead larva and in the process become contaminated with the bacterial spores that are now dormant. The house bees then carry the spores to other bees, and the spores end up either in the honey stores or are fed again to new larva. Thus the disease is spread within the colony rather rapidly.

Robbing is one of the ways that American foulbrood is spread. That is why we mentioned robbing in lesson one. Robbing bees will take back contaminated honey to their own hives which will result in larva being fed with spore laced honey. The disease will spread to many colonies within several miles from the infected hive.

You should always check for American foulbrood when examining your hives. If the beekeeper is able catch this disease early, further spread can be prevented.

We would like to thank the Ohio Department of Agriculture and Mr. Gordon Rudloff for permitting us to use Beekeeping Facts sheets with this course.

European foulbrood is not considered a serious disease. It occurs mostly in the spring and early summer when most colonies are in rapid development. It is noticed in weak colonies and is not spread like its cousin American Foulbrood. Reduced honey yields result but it can be easily treated.

Again just like American foulbrood, young larva less than three days old are infected by bacterial spores fed by nurse bees. Unlike American foulbrood, the larvae die before the cells are capped. The larvae generally have a yellowish cast to them and they are curled up in a cell in a "C" shape. The larvae will not rope as does American foulbrood. If European foulbrood is well advanced and widespread within the colony, the brood may have a shot gun effect similar to American Foulbrood. American foulbrood scales (dried up larval remains) are difficult to remove while European scales are soft and granular and can be removed without much difficulty. However, if European foulbrood is detected, the beekeeper should not transfer frames from this hive into other hives. On particular bad diseased frames, it might be best to remove the frame and burn it. Also see the treatment for AFB. It works for EFB as well.

Chalkbrood is caused by a fungus. Typical signs of this disease are little white chalk like mummies laying on the bottom board and near the front of the hive. House bees remove many of them. The mummies most likely will be white but also are gray as well as black. Good hygienic behavior in a hive of bees is the best defense against chalkbrood. This disease is seen in colonies under stress. The larva die in the cells before they are capped and take on a chalk like consistence in the cell. What can you do: requeening with good stock. Make sure the colony has a good supply of food and add additional bees if the colony is weak. Fungi spores (Ascosphaera apis) are resistant and long lived. Once diagnosed the disease can reoccur if the conditions are favorable. It seems that wet weather conditions favor chalkbrood.

Sacbrood is caused by a virus. Larva die during the prepupa stage. This disease gets it name from the sac that forms from the rubber like skin around the dead larva. Again, the beekeeper might try new stock by requeening, and following good hygienic patterns in keeping bees. We will discuss that in an upcoming lesson.

Click here to go to "PMS" This disease may be mis-named. Many viruses can be associated with honey bees. A combination of mites and viruses often results in a condition referred to as "PMS". One good clue is to look for deformed bees. One may also find what looks like American foulbrood. By the time "PMS" is identified, it is usually too late to save the colony. Please read the Beekeeping information sheet provided by the Ohio Department of Agriculture.

Character	American Foulbrood	European Foulbrood	Chalkbrood	Sacbrood
Cause	bacterium	bacterium	fungus	Virus
Brood comb	Sealed brood Sunken or punctured cappings	Unsealed Brood	Unsealed Brood	Sealed brood Scatted with punctured cappings
Color of dead brood	Coffee color brown to black	Dull white to yellowish turning to brown	White to gray or black	Gray or straw colored and dark
Consistency of dead brood	Soft and sticky Melted down	Watery or pasty	Chalk- hard	Watery, tough sac.
Toothpick test	sticky to ropy--ropes 1" or so	Not ropy	Hard - soft pellet like mummy will pull out.	punctures sac - watery
Odor of brood	Sulfur like - distinctive	Not as noticeable but described by some as sour	None that can be detected unless up close	Little odor
Scales	Adheres tightly to bottom side of cell.	Removes easily.	No scale - just a mummy	Brittle and removes easily.

Sealed brood Sunken or punctured cappings