I agree fully with BSD, in my very limited experience with mites I believe they build a resistance quickly. I am currently alternating between 3 products. One is a chilli and garlic spray (2 litres water, 12 small chilli's and four cloves of garlic, some cinnamon powder and a drop of dish soap, simmer in pot 20m and strain) A broad spectrum product containing Thiamethoxam and an oil based product. Best of luck