Hi all



Of course, you can’t prove anything with the absence of proof, but I haven’t seen one convincing report that comb replacement alone has any benefit to colony health. It may be a way to treat ongoing infections such as foulbrood, but one has to know the cost to production to determine its actual benefit. For example, you may cure foulbrood but if you spend more than the cost of destroying the hive and replacing it, what is the point?



On the other hand, this work done in Argentina attempts to correlate various factors, including comb replacement, with winter loss. These are the factors they looked at were:



Region

Size of apiary

Average winter mortality 

Average honey yield 

Migratory beekeeping

Protein diet 

Carbohydrate supply 

Colony multiplication

Frequency of requeening 

Percentage of requeening

Annual comb replacement 

Wooden ware disinfection

Autumn treatment against Varroa mites

Monitoring varroa infestation level

Late winter–Early spring treatment



They concluded that when they compared all the potential factors associated with winter losses, the number frames of sealed brood, number of  frames of honey, queen replacement, varroa mites and date of acaricide treatment were significantly associated with subsequent colony failure.



Not the other factors. They state: "This supports the fact that weak colonies during autumn, poor queens, and varroa mites are among the top five most frequent reasons given for colony losses.” 



and finally:



"Although we evaluated numerous potential risk factors for winter mortality, queen replacement was the most important driven variable explaining colony losses.”



Agostina Giacobino, Ana Molineri, Natalia Bulacio Cagnolo, Julieta Merke, Emanuel Orellano, Ezequiel Bertozzi, Germán Masciangelo, Hernán Pietronave, Adriana Pacini, Cesar Salto & Marcelo Signorini (2016) 

Queen replacement: the key to prevent winter colony losses in Argentina, Journal of Apicultural Research, 55:4, 335-341, DOI: 10.1080/00218839.2016.1238595



BTW, I have been in touch with people at Penn State and they have told me that they have data to show the most significant single factor for survival is colony weight going into winter. I am assuming this is a reflection of the strength and quality of the colony and not the result of supplemental feeding. The data haven’t been published yet.



PLB









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