Only a field planted with an acceptable source of seed or vegetative stock, as described in these regulations, is eligible for certification. The participant shall maintain for 2 years after harvest of the turf grass, evidence establishing the source of seed or vegetative stock, including such evidence as: A certification tag; An analysis tag; and A bill of lading or invoice. The participant shall make available to the Department the evidence in §B on request. The participant shall maintain a record that shows the variety and lot number of the seed source or vegetative stock used to plant each field.