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Do I need to kill them
After treating I may have 5 mites in spring and 300 in next Autumn. Do I need them. Nothing bad has happened.
Let's suppose that during winter 320 mites has dropped to 100. Next September I will have 6 000 mites.
Lets treat them with efficacy 98%. What means 2%?
3200 …> 64.. ... ... next August 2000 .. Sept 4000 ...Oct 8000
640 …> 13.. ... ... next Sept 800 .. Oct 1600
160 …> 3 .. ... .. next Oct 400
WHAT I TELL: TREAT MITES EVERY YEAR!
If you do not see mites with mere eyes in young bees, you may have 300-500 mites in the hive.
If you see them several with mere eyes, the count may bee about 1000. It needs late summer treatment before winter bees rearing.
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