Sulphur disks 5g (1kg box)

01 · THE DOSE

60-100 g per m³, that is 12 to 20 discs

The working figure is 60 to 100 g per cubic metre of enclosed space. With 5 g discs the arithmetic does itself: 12 to 20 discs per m³, and a one-kilo tub holds around 200. That is what the disc format gains over the strip — nothing to cut and nothing to weigh: you count out the discs the volume calls for and that is that.

02 · ALWAYS FROM ABOVE

The gas is heavier than air and sinks

The work is done by sulphur dioxide, and it is heavier than air: it drops towards the floor of the space as soon as it forms. So the discs are lit high up — on top of the stack of supers, not underneath; doing it from below leaves half the volume untreated. That is what the centre hole is for: a wire threaded with as many discs as you need, hung from the top of the chamber, drum or box. They do not drip as they burn, but put a metal or ceramic tray underneath all the same.

03 · EGGS SURVIVE

Which is why you have to go back

Here is the point that decides whether the treatment is worth anything: the fumes see off larvae and adults, but not eggs. Any already laid will hatch afterwards, so you have to repeat at 10-14 days to catch those larvae, and every 2-3 weeks for as long as the heat lasts. Between treatments, keep the material isolated — sealed drum, bag, airtight chamber — or the moth lays again and you are back to square one.

04 · WHAT IT TOUCHES AND WHAT IT DOESN'T

Empty combs, and metal takes a beating

It is for combs already extracted and empty, above all those that have held brood or pollen, which is what the moth is after. Never over capped or unextracted honey: sulphur changes the flavour. And a fact almost no product page gives: the gas is corrosive to metal parts, so comb wire, nails and fittings show the effect of repeated treatments. Before returning the combs to the hive, air them for at least 24 hours.

05 · BEFORE YOU BUY

Sulphur fumes are toxic and irritant to the airways and eyes, and sulphur burns with a flame. Wear respiratory protection and gloves, light it from outside the enclosed space, do not go in until it has been ventilated, and keep children and animals away.