Integrated Pest Management (IPM) for Varroa destructor

Consider using an IPM method to help control the Varroa mite population in your hives. Two methods I have used are screen bottom boards and Varroa trapping.

Screen Bottom Boards: As the mites attempt to transfer from one bee to another, some fall. A screened bottom board allows the mite to fall out the bottom of the hive. These also help ventilate the hive in both summer and winter. I have not notice a significant "management" of mites with screen bottom boards but I do find them very helpful in monitoring mite levels in a hive.

Drone Brood to Trap Varroa: The first thing to consider with trapping Varroa is why mites prefer drone brood, the chart below explains this.

I have had success in reducing the population of mites with drone frames, also referred to as Varroa trapping. Traps reduce the population of mites by using the Varroa's behavior of preferring drone cells. By providing a place for drone cells the colony will concentrate the drone rearing to one or two frames, I use two frames in the top box of a double body deep hive. After the cells are capped I remove the frames, which will be about 21 days after the frames were installed and along with them all the mites and their offspring trapped under the cell caps. (This timing can change if it is the first time the frames are used since bees will be drawning wax.) Freeze the frames for 48 hours to kill the mites and return them to the hive. The frames can be reused and the bees will even clean them out for you, just make sure the frames are thawed before reinstalling them. Even two rounds of trapping mites, July and August, can significantly reduce the mites in a hive. Look at the pictures by clicking the photo below.

Varroa Trap

I made room for drone frames by pulling frames when making splits. If you are not making spilts make room in your hive by replacing old frames or replacing frames that have a lot of drone cells. Keep in mind that you do not want your other frames in the hive to have an abundance of drone cells and also if you are breeding queens this may be counterproductive.

This frame has a lot of drone cells. Click for a larger image.

There are two popular methods to assess the mite levels in your hive:

• Screen Bottom Boards
• Powder Sugar roll or Ether Roll

What numbers should you use to determine if the colony should be treated?

The most important thing to get from all this is Varroa will kill your hive.