Just because you place a queen in a colony, doesn’t make it mite resistant immediately. No matter the queen, it will take 45 days post release for the colonies population to turnover to the new queens genetics. The VSH (varroa sensitive hygiene) trait is exhibit by workers around day 10 of the bees lifecycle.
That means that the colony won’t start to remove mites from cells until about 60 days post the queens release. This is why we overwinter our queens first before performing the VSH assay typically.
No matter how great the genetics are, all colonies still require management. We suggest to our customers that they test for mites and treat according to their treatment threshold if needed. We have found that 75-80% of our colonies do not require treatment all season. That means if you bought ten queens from us, at least two or three of those queens may not be mite resistant on average. You could get lucky and have 10/10 with excellent mite resistance. The only way to know for sure is by managing the bees during the season and finding out.
Another point to consider, what is your starting mite load? A colony on the cusp of a varroa induced collapse will
not benefit from any mite resistant queen, no matter how great the genetics. A smart move is to monitor for varroa before splitting your colony. Sometimes the best move is to cull the colony so that it doesn’t negatively affect the rest of your yard.
To summarize:
Be patient, VSH takes 60 days before making a dent in the varroa population
Continue to monitor your varroa levels and treat accordingly
Colony survival requires management
Know your mite levels before splitting a colony
Thanks for supporting local beekeeping,
Trevor Bawden
Lloyd St. Bees