The effects of A. apis have been reported to range from ‘transient and not considered serious’ to
‘persistent and damaging’3
. Decreases in honey production of 5%11 to 37%21 have been recorded.
Chalkbrood has been reported to sometimes kill colonies overseas2
but not in New Zealand19. It
often weakens colonies so they are unable to produce a surplus honey crop or sufficient food for
winter5
. However, as these observations relate to naturally infected colonies, it is difficult to assess
whether there is a causal relationship between losses of brood and production and chalkbrood
infections, or whether there are other factors causing the production loss.
As strain differences are reported for A. apis, and significant damage to production is recorded,
chalkbrood will be classed as a hazard.