Dennis Crowley, a commercial beekeeper and president of the local beekeepers’ association, stepped in to talk to participants yesterday (December 2) after the hosts learned of the sudden death of Marcia Meehan, who had planned a day-long workshop.
Interestingly, Dennis said that commercial beekeepers are now looking at more organic, or natural, ways to manage the varroa mite as the pest becomes resistant to the chemicals that have been used so far.
He clarified something that Marcia had said during her November 3 talk at the Garden and Artfest – the icing sugar method doesn’t kill the varroa, just knocks it off the bee. With the way that top-bar hives are constructed that means it falls on to the ground and will live for five days off its host – if it’s covered in icing sugar however, it may well attract a bee and grab a new host! Adding a drawer at the base of the hive might help. The mites could be collected as they fell, removed and burned.
Dennis mentioned some treatments based on the natural chemical thymol (one uses evaporation and a strong scent to drive varroa off and keep others away) and that oxalic and formic acids are also being investigated. Read some information on these treatments here (Ministry for Primary Industries website).
“We’re never going to get rid of varroa,” Dennis said. “We’ve got to learn to live with a low level of it in the hives.”
He described varroa on a bee as the equivalent in size of having a rat on a human body – some bees can have three or four mites on them!
Dennis has a recipe for checking the prevalence of varroa in a hive:
1 glass jar with a gauze lid (Kings Seeds sells the lids)
2 tablespoons icing sugar
Half a cup of bees
Gently roll the jar round three or four times so the bees are coated and shake it over a white board. The varroa will fall out and you will have an idea of the size of your problem. Burn the varroa. Release the bees.
“If you stopped tending to the varroa in your hives now, in six months half your bees would be dead and in 12 months they all would be,” Dennis said.
If a beekeeper has not completed a DECA (disease elimination control agreement, aimed at American foulbrood) his/her hives must be inspected annually by a registered beekeeper.
The workshop was held at the home of Helen and Mike Crosby – the berries on the scones at morning tea were from their garden (thanks, bees) and Mike showed us his plum trees laden with green fruit, as well as the two top-bar hives where the workers live.
There is a free, online book about top-bar hives in New Zealand. The link is to a QuickView (under File there is an option to download the original). The Save Our Bees website includes free plans for a top-bar hive and other useful information.