Iowa Admin. Code r. 21-22.7
If upon inspection an average of more than 10 Varroa mites are detected in 300 bees by the ether roll method or 500 mites per colony by the sticky board method, then the apiary shall be quarantined and the owner of the apiary ordered to depopulate or treat all colonies with an EPA-approved miticide within ten days from the day the owner is notified.
If an average of 10 or fewer Varroa mites by the ether roll method or 500 or fewer mites by the sticky board method are detected, then the apiary shall be quarantined and the owner of the apiary shall be notified and given instruction on the nature of the mite infestation and the best method of treatment. Such treatment of all colonies in the apiary shall be initiated no later than October 15 of the same year
Iowa Admin. Code r. 21-22.7