[grapeman]

Hi,

-On August 25th, I tested for Varroa mites using an alcohol wash. I had a 3.8% infestation rate in my strongest hive (of 3).
-On September 5th, I treated all three of my hives with Formic Pro.
-On October 5th, I tested for mites again in the same hive I tested in August. I had a 21% infestation rate! The Formic Pro seemed to not work at all. I also observed lots of short and/or deformed wings on my bees, clearly suffering from DMV.

My question then is with this extremely high mite count, would it be best to treat with Apivar or an Oxalic acid vaporization? I live in northern MD, zone 6. Thanks for any help you can provide.

 

[psm1212]

My question then is with this extremely high mite count, would it be best to treat with Apivar or an Oxalic acid vaporization? I live in northern MD, zone 6. Thanks for any help you can provide.

I would say that if you currently have a 21% infestation rate and are seeing DWV in your hives, your only real option would be a flash treatment like another shot of Formic Pro or Oxalic acid. Apivar is a contact miticide that works very slowly over a long period of time. I think your infestation is too intense and the timing too late to use Apivar at this time. Formic Pro may have worked on September 5th, but your bees may have robbed out an infested hive sometime between that time and October 5th.

I would use Formic Pro, MAQS or Oxalic Acid. You will be risking queen loss with the formic acid products, but you really don't have much of a choice at this point. Oxalic acid, if sublimated/vaporized would likely require multiple applications over the next month to be effective. I would do it every three days for a month if I could. Also, treat the other two hives at the same time. May all sound a little extreme. But you have a pretty extreme situation.

 

[dudelt]

psm1212 is right on the money with his reply. Apivar is NOT appropriate at this time due to the enormous amount of mites. It works slowly and you need to make a difference ASAP. I would do an OAV treatment every 4 days until 5 treatments are done and check the mite drop two days after each treatment. If the drop is still large after the last treatment, do another until the total drop is minimal.

 

[JWPalmer]

Grapeman, I just came through the same thing. Do as psm1212 suggests and hit the entire apiary with OAV on a tight schedule. The mites will continue to drop in large numbers for the first several treatments so do not get discouraged when you see all those mites falling. Keep at it until the drops are near zero and you will be giving the bees their best chance at surviving. Plan on around 6 or 7 treatments 3-5 days apart. Feed both syrup and brood builder pollen patty and you might get them to produce another round of brood before they shut down. You are about a month behind the point where you want the hive to be nearly mite free, but the bees are pretty resilient if you help them a little. Make feeding shims and keep the hives well supplied. If they make it to Feb., be prepared to give them some brood and bees from your other hives.

 

[grapeman]

Thanks for your responses. This is exactly the kind of advice I was looking for. I have on order a vapor wand and oxalic acid powder and will immediately start using those as directed when they arrive. In the meantime I did put more Formic pro in there the same day I discovered the high mite count for what it's worth.

 

[JWPalmer]

I would do the one week of Formic Pro and then switch to OAV. Temps are pretty good in our area but are expected to warm up a little as the week progresses. I shy away from the formic acid products, especially at this time of year as queens, should you kill yours, are real hard to get. OA will do the job if you are diligent.