I live in Greece and I think I recently had Tracheal mites in three related, side by side hives. Lots of crawlers, K wings, but no bee droppings (so not nosema). Could have also been CPBV.
This occurred after I used Hopguard late winter instead of Thymol. Why do I mention this? Many of the chemicals we use for varroa, both natural and synthetic, also have an effect on Tracheal. Thymol is one of them... so is Amitraz... I haven't seen anything mentioned about Hopguard's effect on Tracheal, so I'm thinking that may be the reason my bees may have had Tracheal mites.
I lightly sprayed the hives with a strong home-made HBH/Thymol solution, and after a few days, the problem seemed to go away, or at least diminish, depending on the hive in question. I'm still monitoring the hives though.
I didn't have the bees checked for Tracheal mites, so yes, there's a lot of conjecture on my part. But I don't think it's coincidental that when many people started treating for Varroa, Tracheal seemed to go away. Maybe the increased use of Varroa treatments killed two birds with one stone, so to speak?
I also think that many treatment free newbees may be losing hives to not only Varroa, but also Tracheal. They may just not know about it.
I only have just over two years experience in beekeeping, so I may be way off.
But I do believe that you can't really know you have those Tracheal mite resistant genetics if you treat Varroa with a miticide that also affects Tracheal.
