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NEW ZEALAND BEEKEEPER, JULY 2017
AFB CONTROL: TIME TO THINK AHEAD PEST AND DISEASE CONTROL Frank Lindsay, Life Member Over the next two years, MPI will be updating and revamping the AFB regulations. This will entail tidying up a few loose ends such as adding to the database so tracing is improved (why have two databases?), allowing for better surveillance and tracing, and changing the financial charges to account for large apiaries.
Diagram of a cobalt-60 sterilisation plant. Photo: Frank Lindsay. Source: http://barc.gov.in/bsg/ftd/faq2.html
It was acceptable to burn woodware and wax but now the majority of our hives have plastic frames to some extent, as this has made the extraction of mānuka honey so much easier. But under the Clean Air Act, we shouldn’t be burning plastic. Regional councils are becoming more concerned with this activity as they are getting complaints from the public. Warming of our climate could exacerbate storage issues of disease equipment by having longer periods of fire bans where we can’t burn anything. Is cobalt-60 sterilisation the answer? Perhaps we should look at encouraging the establishment of a large cobalt-60 gamma sterilisation plant in New Zealand. We already have two very old, small units in the Hutt Valley, but is too small to handle bee boxes and have a 10-week waiting period.
Australia has three modern plants which beekeepers use to sterilise their hives. Diseased hives are packed two supers high (the weight limit is 25kg because they have to be manually handled), double shrink-wrapped and strapped and put through the plant on racks. This process sterilises everything: nosema spores, chalkbrood spores and AFB spores as it passes through the plant, so that the equipment can be reused. Bees bounce back in equipment that has been sterilised; it’s just like putting bees in new equipment. Cobalt-60 sterilisation costs about $A350 for a pallet or about $A10 a box, including frames. Not bad when full replacement costs are about NZ$45, but you can’t have honey in the frames. Even though no heat is involved, honey expands and will start to run everywhere, so we’ll also have to change our regulations to allow honey to be extracted from the supers of infected hives.
New Zealand has an aim to eradicate AFB from managed colonies by 2030 but the growth in the industry and today’s beekeeping practices have made it more difficult to achieve this aim. Whereas years ago AFB was a rarity, today you hear comments that beekeepers now seeing more AFB. In 1996 it was estimated that AFB losses were $2.9 million, according to the AFB website. Hive numbers have doubled since then; yet we have just about the same percentage level of infected colonies, which tells me that the actual number of hives being burnt has also doubled. At the same time, the price of a hive has gone from $250 for a four-high colony to $600–1000 for a single box. The price paid to beekeepers for mānuka honey has tripled since this time, so this disease is now a major threat to the industry’s profitability. Somebody with more time on their hands than me can work out the maths but it’s now probably triple the old figure.
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