Freeze killing

If large freezers are available, colonies can be killed by freezing them, but the placement of colonies into a cool room or freezer will change the distribution of SHBs, because of the resulting clustering behaviour of the bees.

  1. Close all colony entrances with tape, grass, or other similar material.
  2. Place the colonies into a freezer room (< -20°C) for 2 weeks to ensure that all the bees in the colonies are dead. It is important to note that honey bees are able to thermoregulate, so strong colonies with honey reserves (the fuel for thermoregulation) may die slowly. Wherever possible, colonies should be placed into very cold freezers and left for at least 2 weeks. Colonies kept at temperatures > -20°C may die too slowly.

Regardless of which way of killing, the SHBs in the stored colonies are counted as follows:

  1. Thaw the colonies at RT for 24 hours prior to inspection for beetles.
  2. Once thawed, remove the lid to the colony.
  3. Carefully inspect for beetles. Bees should be removed to facilitate beetle visualization and cracks/crevices examined carefully.
  4. Remove all frames from the colony
  5. Inspect each frame for beetles. This includes removing bees from the combs, tapping the combs on their sides to dislodge beetles hiding in the wax cells and uncapping of sealed honey combs to detect mining larvae (Neumann and Hoffmann, 2008). It is important to note that bees cluster in cold temperatures, with many bees clustering head first into empty cells. Beetles often can be found at the bottom of cells that bees are in (Ellis et al., 2003a) so all clustering bees should be removed from all cells (this can be done using forceps) in order to find every beetle present in the nest.
  6. Inspect all supers and the bottom board for hiding beetles.