Varroa resistance definition

[irishbeee]

Checked all colony's in the last week, everything made it through the winter, all colony's were treated apigaurd in September and later with 3.2% oxalic acid dribble in early Jan with the average drop of 10 -20 mites in the first 24 hrs. One colony had a massive drop of 300 - 400 mites in 24 hrs which was far more than i was expecting.The colony with the large mite drop is by far the strongest colony now with bias over 7 frames where other colony's are about 3-4. Would this be a colony that would be considered in someway resistant to varroa? I was expecting it to be a weak colony but it is by far the strongest, any thoughts? The colony in question was a single brood all last year and is stronger than all that were double brood??

 

[Fusion_power]

A resistant colony of bees will keep mite load to a minimum even when it is the largest colony in your apiary. Convert your mite drop to number of mites per 300 bees and the picture will become plainer. A resistant colony drops 1 or 2 mites per 300 bees vs susceptible that usually drop 20 or more.

This is a generalization. Mite load changes during the year with highest in late fall. My colonies tested from 2 to 35 per 300 bees suggesting 3 colonies were very resistant while the others are only partly resistant.