When the department determines a plant pest to be dangerous or destructive to the agriculture, horticulture or forests of this Commonwealth, the pest may be declared a public nuisance. It shall be unlawful for any person knowingly to permit any plant pest so declared to exist on his premises or to sell, offer for sale, give away or move any plants, plant products or other material capable of harboring the pest.
3 P.S. § 258.20