In these days the second treatment against the varroa mite takes place: In the hives, formic acid is evaporated over several days. The concentration in the air of the hive should be just high enough to kill the mites without harming the bees. Depending on the size of the colony and the maximum temperatures to be expected during the day, the amount and the evaporation rate is adjusted by the size of a wick.

The unfortunate bees have to endure this procedure. Even though the treatment is painful, the bees benefit from it by going into the winter largely free of mites and can start the coming spring as healthy and efficient colonies.

However, many of the bees react by staying in large numbers in front of the hives during the day to escape the corrosive climate in the hive. Of course, this pleases the mites that are sitting on the bees... and annoys the beekeeper.

It's part of the deal between the garden beekeeper and his bees: He gets delicious honey, and in return, he offers the bees a comfortable home in a prime location, sugar in sufficient quantity for winter feeding, and a consistent health program in autumn.