Small Hive Beetle
The Small Hive Beetle (Aethina tumida) is an invasive pest that harms honeybee hives and damages the honeycomb, stored honey and pollen. The bees may abandon the hive if the infestation becomes heavy. Native to sub-Saharan Africa, the first small hive beetles were found in the U.S. in 1996 or 1998, by most accounts in Florida. This destructive beetle has now spread to at least 30 states. In 2002 they were found in Canada and are known to be in 6 provinces. Mexico has identified the small hive beetle in 8 states.
The small hive beetle (SHB) is considered to be a secondary pest and generally causes damage in hives that are stressed or weakened by other factors. In a healthy hive, the worker bees will protect the hive from the invasion of the SHB. Once the worker bees are outnumbered by the beetles, the hive can be destroyed quickly.
When bee populations are sufficient and the SHB populations are small, the hive should be ok. However when the population of bees is insufficient or the hive has other factors impacting the health of the bees, the SHB can become an economic issue. It is important to note that both the larval and adult stages of the SHB prey on honeybee eggs and brood.
The feeding habits of the SHB larvae cause visual damage to bee colonies. Larvae tunnel through the honeycomb causing damage and destruction of the honey and yielding a slimy, shiny appearance in the combs; however, they rarely damage the honeycombs.
The adults defecate in the honey and this introduces yeast which ferments the honey. As this occurs, the ruined honey will run out of the honeycomb cells. It will be rejected by bees and is not fit for any type of consumption. This fermentation process produces a characteristic odor of decaying oranges.
The adult beetles are easy to detect with quick visual inspections. When the hive is opened, adult beetles will be found running along the underside of the cover and on the top bars of frames.
The larvae can be found in clusters in the corners of the hive or on the frames. If you find larvae that are scattered throughout the hive – but not in clusters – you are seeing Wax Moth Larvae (the greater wax moth, Galleria mellonella, and the lesser wax moth, Achroia grisella).
The older beetle larvae move toward light sources. One method for reducing their numbers is to place a light source underneath the hive so that these older larvae may exit the hive, falling to the ground. They can be swept up and drowned in soapy water or trapped using Freeman Beetle Traps.
Prevention and Control:
The best prevention is a combination of cultural and mechanical controls. The most important action you can take is to keep a clean apiary. Here are some other ideas for reducing the attraction of SHB to your bees:
- Do not toss burr comb onto the ground.
- Place hives where they receive direct sunlight as the beetles prefer shaded hives.
- Keep the hives and frames in top condition. Wood that is rotting or warped or has holes in it provide safe harbor for the SHB.
- Clean bottom boards regularly or use screen bottom boards so that debris doesn't build up and provide prime pupating habitat for the SHB.
- Use mechanical traps such as the Freeman Beetle Trap to replace the bottom boards.
- Apply the beneficial nematode, Heterorhabditis indica, to the soil beneath and around the bee hives.
The use of any insecticide that might control the adult or larval stage of the SHB will have an adverse effect on the bees. Therefore, there are no organic insecticides recommended in controlling this pest.