Close the entrance to the hive
The entrance of a diseased hive is normally closed before killing the bees in the colony. Beekeepers usually close the entrance with folded newspaper or long grass stuffed into the entrance. Folded newspaper is preferable, since the bees can sometimes find openings in the grass and will fly out during the killing process. Grass can also sometimes become dislodged during transport, resulting in dead bees falling out onto the ground, or be removed by stock if the hive is left on site.
Seal the cracks
t is also important to seal all the cracks in the hive, since bees will use these cracks to fly out during the killing process. Cracks can be filled by covering with masking tape or by pushing small pieces of newspaper into the cracks with the end of the hive tool.
Best time to destroy the hive
Hives infected with AFB are usually closed and destroyed either in the evening, or during rainy weather, when the bees are not flying. This is done to avoid field bees from the AFB hive flying into neighbouring colonies and possibly spreading the disease.
Because hives infected with AFB are usually found during the daytime, and closed up to be destroyed at night, a second visit to the apiary is generally required. This can create extra costs for the beekeeper, especially when the apiary is a long distance from home.
Although it is preferable for all bees to be inside the AFB infected colony before the entrance is closed and the colony is destroyed, researchers have found that it is possible to kill colonies while the bees are still flying with little risk of spreading the infection.
A trial was conducted pairing colonies with low level infections (i.e., less than 50 larvae/pupae exhibiting AFB symptoms) with colonies not showing any symptoms. At the start of the trial, the pairs of colonies were set up so that their entrances were touching and facing the same way. At the start of the trial, the researchers made sure that one of the colonies had AFB, while the other colony in the pair was uninfected. Then the AFB colony was closed and removed on a sunny day between 1.00pm and 3.00pm, so that foraging field bees from that colony were left behind. The researchers found that most of these field bees flew into the second (no AFB symptoms) colony in the pair.
The trial was repeated with 25 pairs of colonies. Interestingly, none of the colonies remaining behind developed visual symptoms of AFB.