We have one chemical that is working well on the varroa mites. We're on year four, year five now, so it's due to run out any day. We don't have anything to replace it yet.
It's definitely a concern of the industry. As beekeepers we have to be conscious of what we put in our hives and make sure that we are using it according to the label. If we overdose or overexpose, resistance will happen that much faster.
We need to have enough alternatives on hand to have rotation to reduce that resistance and to ensure that we're producing a safe and healthy food product. We have to be cautious of what and how much we put in.