Spring is always the most exciting time of year for beekeeping, and as part of your regular spring maintenance there are some important steps you can take in the fight against the varroa mite.
In June 2022, Varroa destructor mites were detected in beehives linked to Newcastle port. Since then, NSW DPI has been leading a campaign to try to eradicate this pest before it becomes established in Australia. Because of this, certain restrictions on beekeeping have been enacted. These regulations are changing frequently and vary from state to state, so make sure to keep up to date with news and regulations from your state’s official agricultural body.
IMPORTANT: At present in NSW, there are certain restrictions around the movement of bees. Please check for updates from the DPI.
What is Varroa?
Varroa destructor is a pinhead-sized mite that parasitises honey bees and their brood. They can severely weaken the bees, and also carry damaging viruses.
The mites live on adult bees’ abdomens and feed on tissue called the “fat body”. The mite reproduces inside brood cells, with the young mites parasitising the developing bees.
Adult Varroa mite on a nurse bee
Varroa mites on a developing bee larva
Adult varroa mite closeup
Adult females are a rusty red-brown and measure 1-1.8 mm (around 1/16 inch) in length. They are round and flat, and can be seen with the naked eye, especially when against a light-coloured background.
Varroa mite numbers build up in a hive of European honey bees over time, eventually killing the colony if chemical treatments or other management strategies are not applied. This can have a significant effect on large-scale honey production and pollination of certain food crops.
How Beekeepers Can Help
While the current incursion is being responded to, there are some simple steps beekeepers can take to support their bees and the wider effort to keep Australia varroa-free. The good news is these practices are all part and parcel of your standard spring beekeeping activities!
Register your hive
All beekeepers in Australia should make sure their hive registration is current, and monitor updates from their state's official agricultural body.
Check your hive for Varroa mites
There are a few different methods you can use to monitor your colonies for Varroa. These can be incorporated into your regular brood inspections.
This method is a quick and effective way of detecting varroa mites. It involves taking a sample of adult bees from the hive and washing them with alcohol.
This method works on a similar basis to the alcohol wash method, although it is less effective it has the benefit of not killing bees.
Because varroa mites prefer to reproduce on drone brood, uncapping drone cells is a quick way to check for varroa that requires little equipment.
Putting a sticky mat at the base of a hive can help to detect mites, but should be used in conjunction with other more effective monitoring techniques.
Swarm prevention is an important part of managing honeybee colonies, especially in the springtime. The varroa outbreak has made this all more vital than ever. The mites can spread through swarms, so it’s that as beekeepers, we do everything we can to control swarming this coming season.
Swarming takes place most frequently in springtime when there is a lot of nectar and pollen available and colonies are expanding rapidly. There are some telltale signs you can use to determine whether a hive may be preparing to swarm.
A lack of space for the queen to lay eggs in is the primary trigger for a colony to swarm. There are several ways to alleviate this:
Split the hive - start a new hive by taking half the frames from the brood box and putting them in a new box. - For beekeepers in NSW it’s important to note that although there are certain restrictions around the movement of bees, the DPI have advised us that splitting for swarm prevention is allowed outside the red emergency zones as long as the original hive and new split are not moved from the original hive location.
Add an extra brood box or super - this gives the queen more space to lay in.
If you find queen cells during an inspection, destroy them. This is on its own is unlikely to stop a colony from swarming, but it can delay the swarm and be effective when combined with alleviating crowding in the hive.
Swarming usually occurs in spring. During winter, prepare your equipment so that you are ready to make splits and add boxes to your hives.
If you don’t want to expand your apiary, find another beekeeper who does and can take a split from you if necessary. - N.B. Be aware of any restrictions on moving hives in your area.
Tip: If you’re worried that a hive is getting ready to swarm but don’t have time to do swarm prevention, you can attach a queen excluder to the hive entrance. This can temporarily delay the swarm until you have time to take action.