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Scientists identify culprit behind biggest-ever U.S. honey bee die-off

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186 points pseudolus | 1 comments | 01 Jul 25 10:35 UTC | HN request time: 0.28s | source
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mrweasel ◴[01 Jul 25 16:27 UTC] No.44435534[source]▶
As a Danish beekeeper: Who the hell uses a pesticide in their beehives?

I agree that keeping mites under controls is tricky at best, but I've never heard of anyone using a pesticide. Normal practise, even for commercial beekeepers is to use oxalic acid. That's not really something mites become resistant to. The other option is brood control, where you basically do a period of time with no brood, leaving the mites without the ability to reproduce. I can see the later not being tricky for commercial beekeepers as that is a lot of hives to manage. The same goes for removing drone brood during the summer, it helps a lot, but I wouldn't want to do it to hundreds of hives.

More and more I feel like the right option is the breeding of mite restistant bees, but that would entail doing nothing for a long period of time or crossing European honeybees with Asian varieties that can remote the mites themselves. The work is already being do, but it's still years away. We have found wild beehives, including abandoned beehives, which are fairly mite resistant.

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ted_dunning ◴[01 Jul 25 18:35 UTC] No.44436826[source]▶
What are the bees in your hive doing when you are using this oxalic acid?

Or if you have no brood for a period of time, I can see that this would decrease the mite population in the empty hive, but wouldn't the brood carry the mites with them wherever they have gone?

(these are serious questions, not challenges)

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1. mrweasel ◴[01 Jul 25 19:04 UTC] No.44437041[source]▶
You put the acid in the hive, in an evaporator. The air in the hive then becomes acidic enough to burn through the exoskeleton of the mites. Technically it also damages the exoskeleton of the bees, but that's thick enough that the bee doesn't notice. You normally do this over a period of 14 days in late summer, early autumn. As the other commenter points out formic acid is also an option.

For brood control, you have two options. One is to insert special frames in the hive, these are designed to encourage drone brood to go in those frames. Mites (Verrora) attack drone brood more as the cells are bigger and can better accommodate the mites. So you concentrate the mites in those frames. Then every week you remove 1/3 of those frames and discard it. That's normally enough to keep the mites at bay. The second option is to trap the queen, she stays in the hive, but she's restricted from moving around and laying eggs, i.e. you keep her away from the cells in the frames. A brood cycle is 28 days, but mites don't live that long. Without any new brood continuously cycling, they can't reproduce as they mature in the brood cells. The down side is obviously a large temporary drop in you bee population, meaning less pollination, and less honey. I don't know many who do this, but from what I'm told it is very effective. I my guess is that you probably only want to do this to fairly strong/highly populaces hives.

The acid and drone frames are normal practise, carried out by all beekeepers. Minus those who experiment with breeding mite resistant bees.

So the hive is never empty, you just create an environment that's harmful to the mites. Either by being to acidic or not providing a place for their eggs to hatch.