On 06/04/16 14:00, Ari Seppälä wrote in regards to Chalkbrood reappearance in restocked sterilised equipment: "In Finland it is common to shake swarm AFB hives. The treated hives show supricingly often chalkbrood, and it must come with bees as nothing else is transferred to the new hive from old. I think it breaks out so easily because bees have hard time starting from just foundations in the new hive. Its interesring that same happened with irradiated that are drown combs." Peter Loring Borst 2016-04-04 17:48 stated: "As I said in a previous post, I had 400 or so hives irradiated, put fresh bees into the equipment and they soon broke down with chalkbrood." Irrespective of whether or not the irradiation dose was adequate to kill spores of Ascophaera apis, (the causative organism of chalkbrood) in the equipment, those spores are ubiquitous in the environment and any bees used for restocking are very likely to be carrying them. One spore is enough to reestablish infection. The real take home message however, is that if you are seeing chalkbrood at all in your hives, then the genetics of those bees are non hygienic. It really is as simple as that. So breakdowns of chalkbrood and AFB are to be expected, especially if stresses such as nutritional limitation or excessive demand for new comb establishment are placed on them. The solution is simple. Test for hygienic behaviour...in your apiaries...in your nucs, and especially those hives used for breeding stock. Test the hygienic behaviour of new queens sourced from outside suppliers. The pin-prick method is quick, cheap and effective. Anybody can do it. Once you have those results you can take effective remedial action, even if it means changing the source of your queens, or putting pressure on your supplier to improve his or her breeder selection. PeterD In Western Australia where a long hot and dry summer has been really tough on both the bees and beekeepers. Ideal conditions for disease breakdowns. *********************************************** The BEE-L mailing list is powered by L-Soft's renowned LISTSERV(R) list management software. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html