About Viruses and Fungal Diseases

Chronic Bee Paralysis is another of the viral infections that can plague a bee colony.  Like all of the other bee viruses there is no cure or medication that can be taken to eliminate the infection, the only preventative measure is sanitation.

There are clearly defined symptoms with the Chronic Bee Paralysis.  It only effects the adult bees.  The symptoms are an abnormal trembling in the wings and body, the bee’s inability to fly which forces them to crawl on the ground and crawl up the blade of grass in front of the hive.  The abdomens will be bloated and the wings will be partially spread or seem dislocated.  The infected bees will appear shiny and greasy because of the lack of hair, which has been confused with robbing bees.  Also, the infected adult bees are chewed on by the other bees and harassed by the guard bees at the entrance to the hive, which is also confused with signs of robbing.  Adult bees will die within a few days of the onset of the disease.  The virus is spread from bee to bee by prolonged bodily contact or rubbing which causes many hairs to break exposing live tissue.  The virus can not be transmitted by food exchange of the bees.  It takes many millions of virus particles are required to cause paralysis when given to a bee in food.  Requeening is a good practice if symptoms appear. 

Another virus that bees are susceptible to is the Black queen cell virus.  It is associated with Nosema disease and causes the death of queen larvae or prepupae after their cells are sealed.  Th larva will then turn black along with the walls of the cell.  Treating colonies with Fumidil-Bâ to control Nosema may help keep prevent this disease.

A fungal disease that plagues the bee colonies is called Chalkbrood.  The fungus that causes Chalkbrood is called Ascosphaera apis; it was discovered here in the United States in 1968.  The fungus spores must be ingested in order for infection to occur.  It only infects larvae 3 or 4 days old.  There are no chemical treatments for this disease.  However, bee breeding and good management can control it.  The infected larvae are quickly covered with the white cotton-like mycelium of the fungus, which eventually fills the entire cell.  The white/gray mass soon will harden into a hard, shrunken mummy, which is easily removed from the cell.  The larvae in the cell will look like a piece of chalk.

The bee bred to be resistant to this disease can help minimize outbreaks of t his disease.  Another way to cut down on the number of outbreaks of the disease is to maintain a warm, dry hive interior.  If the hives are drafty, damp, lying in low spots or in heavily overgrown area, they are more susceptible to chalkbrood disease.  Rain water need to run out of the hive instead of accumulating, so stand the hive with it leaning forward slightly.  If a hive gets moist, prop the lid of the hive open to air out the interior.  Old equipment should be replaced or repaired if it has large holes that permit entry of moisture and drafts.  

There is a possibility of genetic susceptibility or old combs that are harboring spores of the disease if the colonies have recurring problem with the disease that are not easily traced to season or management practices.  Old combs should be replaced periodically to improve brood production.

Responses