This is the time of year when having done all the hard work in Autumn preparing their bees for winter, beekeepers have to rely on the bees to look aft...
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January 10, 2016
Varrox Vaporiser - My newest weapon against Varroa.
January 16, 2016
Varroa Destructor is one of the main reasons why many bee colonies don't make it through Winter. If not controlled throughout the year, this parasitic mite can debilitate the colony to the extent that they will be considerably weaened for Spring or potentially even die off.
Most beekeepers will treat their bees for Varroa at the end of the season in late August or early September once the honey has been taken off the hive and the temperatures are favourable. A variety of different products are available, many using thymol or formic acid, all of which have little or no effect on the bees but are toxic to Varroa. We beekeepers then have a choice to give a second treatment to our bees during midwinter as generally bees are not rearing brood during this period (varroa's breeding cycle requires bee larvae for their young to feed and grow). We cannot use the same treatments we used in the Autumn as temperatures need to be 15 degrees or above for them to be effective, as a result we can use a chemical called oxalic acid instead which again has little or no effect on bees but is deady to Varroa.
Until now, when I have treated bees with oxalic acid, I have used a technique called 'trickling' where a solution of sugar syrup mixed with oxalic acid is trickled over the top of the bees, coating them and killing Varroa. This isn't the nicest of experiences for the bees as temperatures are often chilly considering it is mid winter and as a result it causes stress to the colony.
We now have a new weapon to take to the Varroa, vapourisers!
This simple little device is a metal tray with an electrical supply taken from a 12V battery. The tray is designed to take oxalic di-hydrate which is then heated once the battery is connected. The liquid then vapourises and rises into the hive, filling every nook and cranny with a fine dust of oxalic within about 1-2 mins. The Varrox instructions suggest one spoon (1g) for a one box hive and 2g for a two box. From speaking to others and from more recent UK study, it has been suggested that 2-3g is more effective. I used 4g on my double boxes as application was under the open mesh floor.
Beforehand it is really important to ensure you are wearing the correct safety equipment. protective gloves, goggles and appropriate face mask, oxalic acid is a hazardous substance and is toxic to humans. Before treating the hives I also sealed off the entrances with tape to ensure none of the vapour escaped, the tape can be removed 10mins after treatment. Once prepared the battery was connected and with the vaporiser wedged under the open mesh floor it was allowed to run for about 2 mins until all had dissipated and then the battery was disconnected.
I managed to treat 9 colonies today in the short time I had, I found it fairly easy to do and felt it was kinder to the bees than opening them up to the cold and trickling liquid all over them. I cannot be sure how effective it will be as some of the colonies appear to be brooding and as a result most of the varroa will be inside the cells and unreachable by the oxalic... I'll check the hive inspection trays in the next few days and let you know (with pictures) if we've had a good drop of varroa mites from the hive. Some may ask why we put harmful substances like oxalic on our bees, what I would say is that oxlaic acid does far less damage to a colony of bees than varroa would if left untreated.