Mite longevity
"I was amazed that some of the mites survived that long"
Yes, these mites are very strong and we have a lot to learn... Last year, we kept 2 sticky boards to show at the evening beekeeping class, how Varroa look like to inform beginners. The boards rested 3 weeks, inside a non heated local, away from the hives, it was in october 2016. What was my surprise, when some students claimed some Varroas were still alive and moving. At first, I said it was not possible because they had been minimun 3 weeks without a meal. But yes, some were still alive. How is it possible ?
Randy and All,
When you do the OA vaporisation, if you are using Varrox (very slow to operate), the fumes will stick to 2 or 3 frames maximum. You can easily see it using an empty hive and check where the white OA cristal coating occurs, it's not even covering the entire 3 frames. In winter, the bee cluster prevent the fumes to go inside the cluster. And the effect of OA will only start, when the cluster brakes and collects from the coated frames, the tiny white cristals with their hairs.
Even if you use air blow to inject the OA fumes (improved varrox, much faster), if the cluster is formed, it will not penetrate inside the cluster. The Varroas are protected inside the cluster and will only be damaged when the bees move toward the coated frames. It is therefore difficult to fix a delay in between 2 vaporisations because you are relying on the behavior of the cluster according external temperature. If the temperature is high enough to the point the cluster is not formed, then yes, the effect starts immediatly.
When you do OA dribble on the cluster, the OA liquid solution passes from bee to bee by gravity inside the cluster and it is more rapidly spread. The bees will not eat the oxalic acid sugar solution but will try to escape from that solution. If part of the Varroa falls on the sticky board during 2/3 days, a good proportion is also dislodged during the winter cleaning flights in front of the hive during one week. I have noticed this by placing a large piece of glass about 2 m² in front of the hive. They are easy to spot then.
Regarding your interogation you can :
- coat a petri dish with OA fume using Varrox and place live Varroas inside.
- place a blotting paper with a wet 1%, 2% max OA in the bottom of a petri disch and place live Varroas inside.
- place varroas inside a petri dish to understand their live expectancy without meal.
See which solution is best to kill them and how long it takes, I'll try do it ; I'll have spare time, beeing soon retired...
For me, Varroa sticky pad is the weak point of this warrior.
Regards
Georges
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