Mite Control

Tonight was the night that the green nuc was treated for mites with OAV.  If you'll remember, the queen was isolated in a push-in cage 25 days ago.  Six days ago, she was released back into the colony.  Any brood that was in the hive prior to her being caged would have emerged from its capped cell by now and any eggs and/or larvae that she'd laid since being released would not yet be old enough to be capped.  Therefore, every brood cell in the hive should be uncapped.  And that's when OAV works best.

Oxalic Acid Vaporizer.  Note, you should not put a car battery on concrete.  I got that lecture from my husband earlier.

For those of you who have never done oxalic acid vaporization, it's really not as daunting as it first seems.  You have a vaporization wand and a battery.  You should always follow the directions that came with your unit.  My particular model says to put 1/2 teaspoons of oxalic acid (wood bleach) into the reservoir, insert the wand all the way into the hive, and drape a damp towel over the entrance to seal the entrance.  Then hook the unit up to a car battery for three minutes, and only three minutes.  Then unhook the unit and let it cool for two minutes.  Finally, pull the wand out, but leave the towel in place for another 10 minutes.  So, in 15 minutes you're done.  Easy peasy.

While I was waiting on the 10 minutes to be up, I decided to take a peak at the light green hive.  This one has been giving me fits for awhile.  I now believe them to be the source of the excessive amount of crawling bees that I've been seeing on the ground.  Some of the crawlers have either K-wing or deformed wing virus, which I've also seen inside the light green hive.  Dissecting the midgut shows tan, healthy-looking intestines.  That hopefully rules out nosema.  I decided to do a quick alcohol wash to get a mite count.

An alcohol wash is simply taking about 1/2 cup of bees and putting them in a jar with isopropyl alcohol.  A half-cup is somewhere around 300 bees.  I try to take these from the broodnest, that is a middle frame that has capped or uncapped brood on it.  Make sure the queen is not on this frame.  Shake the frame into a large tub or container.  I use the top of an old Tupperware cake carrier.  One of those under-the-bed Rubbermaid boxes would probably also be ideal.  Now that you've got a thousand upset bees in your big container, simply (ha!) use a household measuring cup to scoop up a half-cup and put them in a jar.  I use a pint-sized, wide-mouth glass mason jar.  I used the band that fits the jar, but instead of the lid, I cut out a circle of #8 hardware cloth cut to fit inside the band.  Slap that lid on the bees and then pour the alcohol over them.  Now it's time to shake, shake, shake.  Then pour the alcohol back through the hardware cloth into a light colored bowl.  Repeat until no more mites come off.  You can reuse the alcohol by pouring it back into the jar.  I don't love having to sacrifice bees, but if it helps the colony survive then I can live with it.

Alcohol wash with bees that made the ultimate sacrifice

The results of my alcohol wash were, as expected, not great.  I found 11 mites.  That's just under 4% infestation rate.  Randy Oliver (who's website, Scientific Beekeeping, rocks) suggests a target threshold of 1%.  In addition, Keith Delaplane recommends a jar count of no more than 7-19 mites in the fall for my region.  So, something's gotta be done.

Ewww.  Okay, so some of these spots aren't mites, but most of them are.  

I considered treating with a series of OAV treatments, but decided to give the queen isolation method another try.  I caged her tonight.  I'll cut out the queen cells this weekend and uncage her on Father's Day.  One thing I did with this hive that I didn't do with the last hive was to cull drone comb.  It wasn't exactly planned this way, as I didn't have any drone frames in this hive.  They just happened to have built a large portion of their drone comb on a single frame.  I pulled it out and put in the freezer.  I'll give it back to them this weekend when I cut out the queen cells.