A promising but far from scientific experiment with sorrel leaves as a mite treatment
A week ago I did an alcohol wash and got a pretty bad result, with an infestation rate of 32%. Since some of the major mite treatments use oxalic acid, I thought it would be interesting to try using sorrel leaves, which contain oxalic acid, as a treatment. I have a couple sorrel plants, so if it worked, I would have a free, renewable mite treatment.
I had seen a bit of discussion online about using rhubarb and sorrel. The idea was that, since bees will try to remove any foreign objects from the hive, they will chew up and drag out the leaves in small pieces. By chewing the leaves, the bees release the oxalic acid slowly over the course of days, resulting in a slow release treatment.
I picked a good bunch of sorrel leaves and layered them on the tops of the frames so that they pretty much covered the top of the box. I did so on the tops of each box in the hive.
After the first day or so, I started seeing dried up, shredded leaves piling up outside the hive entrance. I have a removable bottom board, which I pulled out every day, several times some days. Each time I pulled it out, I saw (and squished) mites numbering in the high teens to twenties.
Today, a week on from the last alcohol wash, I did another and found an infestation rate of 22%. How does that compare to commercial treatments? I'm not a very experienced beekeeper, but this seems like a considerable improvement. I went ahead and put more sorrel leaves in the hive before closing it up.
Obviously it's not scientific. It's only one hive, and only two measurements observing a single treatment. But it does appear to have worked reasonably well. Has anyone else here experimented with sorrel, rhubarb, or other oxalic acid containing plants? What were your results?