Why we treat with Oxalic Acid in late fall

A beekeeper treated her hive with a vaporizer last Saturday morning. It was around 40 degrees. This pic shows the mite drop two days after treatment. Actually it takes seven days for the full effect of the Oxalic Acid to be seen. But, after two days the mite drop was huge. She did treat with Mite Away Quick Strips in August but her hive was reinfested over the course of the fall.
Now her colony will be much more healthy for winter without the parasites on the bees all winter long.

All the red spots are mites. There are hundreds of them that dropped on the screen bottom board after two days. There will be more after the full seven days after treatment. This hive was treated in August with Mite Away Quick Strips it was reinfested over the course of the fall. The late season Oxalic Acid treatment is very effective.