In article <[log in to unmask]>, [log in to unmask] writes >Chalk brood is a fungus, and hence, not considered life threatening to bees >resulting >in little active scientific research. Chalk brood is a funny thing which, in our experience is not the result of any single factor. We have noted it occur frequently in many colonies in spring when perhaps they are struggling a bit to kept the rapidly expanding brood nest warm enough, yet six weeks later in the same colony, with no change of queen, no relocation, no new combs, it is gone. Only differences are that the weather is warmer and the colony stronger. Occasionally we get a colony (probably 1 out of 1700 every other year) which is some kind of genetic runt whereby it is not able to prosper because of chalk brood. The combs can almost rattle with it. In that case we just kill the queen and unite to a healthy neighbouring colony which soon tidies it up. > I found that hives that had OLDER COMB, enjoyed the coolness of >wooded >shade and lack of direct sun, and close to water that might have elevated the >humidity (dampness) were those most likely to exhibit CB mummies. I would agree with all these factors except the old comb bit. We have OFTEN noticed the worst chalk brood cycle being the first one on newly drawn foundation, after which it gets tidied up and is fine. Most times the new comb is fine but it is surprising how often chalk brood goes for the first cycle only to fade away thereafter. We see no great correlation between older combs and chalk brood. >I don't expect any direct research on CB, but the research related >to >HYGIENIC bees might uncover a lot. Genetic factors will have a large part to play in this, whether it is hygienic behaviour or some other resistance mechanism. For example, any bees we have had off the New World Carniolan have shown chalk brood only rarely and I am certain this is not hygienic behaviour that is responsible for this. Reason? No, or very few gap cells in the brood. The 2" square test on an area of similar age brood shows few, and occasionally zero, gaps. So there have not been the infected larvae there to begin with. Other strains in the same apiaries can have significant amounts of chalk brood and/or gaps (which could be CB or sex allele related) present. I would also disagree with whoever said that it is not an important disease. It is definitely economically damaging, as raising that brood which dies is an expenditure of energy and a loss of a percentage of your foraging force two or three weeks later, a loss which is continuous throughout the period chalk brood is active, and over a period can add up to a measureable loss of crop. 'Clean' colonies noticeably out perform, and accelerate away from, 'infected' ones. Thus I would suggest that chalk problems are related to a number of factors, which are detrimental to the bees ability to deal with the underlying cause, fungal attack. Genetic factors are very important, but mild chilling, dampness, and colony strength are also definite contributory issues. Finally, we have noticed for many years (long before varroa predation) a particular tendency for chalk brood to attack areas of drone brood at certain times of the year. We see worker brood on the same comb clean or at least nearly so, and the drone a horrid mess with almost every cell turned chalk. We cannot see any other factor at work here apart from the longer development period of drone brood giving the fungus more time to act at the critical point in the larval stage. If this is so we could have another genetic factor at work not yet touch on, that some bees exhibiting resistance have a relatively short infection window due to variations (possibly only slight, but significant to the fungus) in the duration of critical stages of brood development. >Happy New Year! And to you too George! Murray -- Murray McGregor