505 ILCS 90/13
It shall be unlawful for any nurseryman or nursery dealer to sell, give away, carry, ship or deliver for carriage or shipment within the State any nursery stock unless such nursery stock has been officially inspected and a certificate covering the same has been issued by the Department stating that said nursery stock has been inspected and found apparently free from insect pests and plant diseases. It shall, however, be the privilege of a nurseryman holding a valid certificate covering nursery stock grown by him or holding a valid nursery dealer's certificate to ship under said certificate nursery stock grown for him elsewhere or purchased by him from other nurseries, provided that all such nursery stock when required is received under an official certificate acceptable to the Department stating that it has been inspected where grown and found to be apparently free from insect pests and diseases.
505 ILCS 90/13