Swarm Biosecurity

Thursday 2 June 2022

Sometimes free things can be costly, as may be the case with a honey bee swarm. With swarm season upon us, it is a good time to consider what to do if you spot a swarm that isn’t from your apiary. Swarms, brought into your apiary, may present a risk for the rest of your bees. This week’s blog is on catching ‘free’ swarms and the biosecurity measures that should be considered when doing so.

Swarm Biosecurity

For honey bees, swarming is a natural reproductive process but there are also other reasons for a colony to leave a hive. In absconding, there could be an attempt to ensure the colonies health through reducing disease or pest pressure by leaving behind mites, bacteria, or fungus and relocating to a new fresh home. If a colony swarms due to hive congestion, the mother colony may still be infected. So when we find a swarm there is no immediate indication of the disease status or reason for the bees relocating. Vertical transmission of pathogens may occur between the colonies and spread to another apiary.  When a diseased or pest-ridden swarm is relocated within or near an apiary, it has the potential to impact on the health of all the colonies in that yard.

Honey bee swarm on a tree branch (Photo: Tim Howell, South Carolina Blackwater Beekeepers Association)

Where possible, understanding the background on a swarm will help identify the level of danger but usually very little information is available. A best management practice would be to assume that a caught swarm presents a high biosecurity risk and the colony should be quarantined. A quarantined area should be far enough away from other apiaries to prevent robbing and drifting. Equipment from quarantined hives should not be immediately used in other hives. All hive tools should also be disinfected by torching after working in quarantined hives.

The honeybees in the quarantined swarm can be inspected and tested for certain pests and diseases. Varroa mite testing can be done on site by using an ether roll, alcohol wash, or sticky board. Methods for testing and economic thresholds can be found in the Summer Disease and Pest Monitoring factsheet by ATTTA. Samples of adult bees can also be tested for Nosema. Atlantic beekeepers are welcome to send samples to ATTTA for nosema diagnosis! Once brood production begins inspection for diseases, such as American and European foulbrood should be undertaken.

Swarms from unknown sources can be more damaging, and costly, to your apiary than beneficial. With best management practices, such as monitoring, testing, and quarantining, the risks that come with collecting swarms can be reduced. Also, using best management practices can help reduce swarming, and the potential spread of pests and diseases to neighboring apiaries. 

Written by John MacDonald, ATTTA Seasonal Apiculturist johnmacdonald@perennia.ca

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