Resistant varieties must be officially approved by USDA as well as Michigan Department of Agriculture, prior to sale or transport. Counties included in the USDA Forest Service publication List of Counties and States with Known Hemlock Woolly Adelgid Infestations . Hemlock seedlings and nursery stock, logs, lumber with bark, uncomposted chips with bark and uncomposted bark . All regulated articles originating from or held in an area under quarantine are prohibited entry into Michigan unless treated with a method approved by the Director of Agriculture. Regulated articles from non-quarantined areas must be accompanied by a state phytosanitary certificate or certificate of quarantine compliance.
Additional restrictions apply for hemlock wood products with bark.
Nursery stock transported through quarantined areas must be safeguarded from infestation.