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NEW ZEALAND BEEKEEPER, NOVEMBER 2016
SMALL HIVE BEETLE: AN OVERVIEW AND DIFFERENTIAL DIAGNOSIS PEST AND DISEASE CONTROL
Byron Taylor, Apicultural Officer, AsureQuality Limited, Hamilton Byron.Taylor@asurequality.com
The small hive beetle (SHB) is a small brown to black beetle approximately five to seven millimetres long and three millimetres wide. The larvae of the beetle look like lesser wax moth larvae; however, a trained eye will note spikes on the larvae. Additionally, the larvae are considerably hardier than wax moth larvae, with beekeepers commenting that they are hard to ‘squish’.
Life cycle Small hive beetles are highly attracted to beehives. Researchers have suggested that they can detect some hives via chemical signals from more than 10 kilometres away. Once in the hive, females will begin laying eggs in cavities away from the bees. Egg incubation time varies but is usually between two to four days. The larval stage is the most destructive. Larvae consume brood, pollen and honey and produce a slimy substance on the comb which acts as a repellent to the bees and renders any affected honey crop worthless. Pupation happens outside in the soil adjacent to the hive and is the stage during which the beetle is the most vulnerable. Larvae can sometimes be seen massing on the floorboard of the hive in preparation for pupation. Pupation takes anywhere from about eight to 60 days depending on temperature, soil moisture, soil structure, etc. On completion of this stage, adults emerge from the ground, ready to infest new colonies. Behaviour The small hive beetle is a strong flyer and can easily travel with a swarm to a new nesting site. However, when a hive is disturbed, SHB will run from the light looking for somewhere to hide rather than taking flight. Small hive beetles will also overwinter in the bee cluster, increasing the temperature range over which the beetle can survive. All parts of New Zealand have a suitable climate for SHB to become established. However, SHB will do better in the warmer areas. Contrary to the adults, larvae will move towards the light. They are a similar size to
Courtesy The Animal and Plant Health Agency (APHA), Crown Copyright
the lesser wax moth larvae but unlike the wax moth, which leaves webbing which many will be familiar with, SHB larvae leave slime on the comb. In terms of hive management, a key consideration is that weak colonies are susceptible to invasion by small hive beetle. becoming established in New Zealand, most beekeeping enterprises will need to reassess their management practices and make changes in order to minimise the impact of the pest. This includes both hive management and harvest/processing management. In terms of hive management, a key consideration is that weak colonies are susceptible to invasion by small hive beetle. Weak colonies are not necessarily those that have been managed poorly and may include: overwintering nucs, queen-raising operations, hives with high varroa levels, and hives suffering pollination damage (spray poisoning, hives under nets, etc). With harvest and processing management, one of the key considerations is that undefended combs are susceptible. This means that we may need to reconsider these factors: storage of harvested honey supers pre- and post-extraction, management of old combs, management of cappings wax, and general cleanliness around honey factories. Management In the event of the small hive beetle
Control measures will add expense in the form of additional visits to hives, pest traps, soil treatments, refrigeration for super storage and so on. For those involved with live bees, at the very least, this trade would be interrupted and depending on negotiations, possibly halted.
Spread of small hive beetle and introduction potential
The small hive beetle is a native of Sub-Saharan Africa but in the last 20 years has spread to many other parts of the world. It has been discovered in Florida (1998), Egypt (2000), Australia (New South Wales and Queenland (2002), Canada (Manitoba 2002; Quebec 2008), Portugal (2004), Jamaica (2005), Mexico (2007), Hawaii (2010), Malaysia (2011), Cuba (2012), El Salvador (2013), Philippines (2014), Italy (2014) and Brazil (2015).
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