The director, after investigation and hearing, may refuse to issue or renew a license, or may suspend or revoke a license, if he determines that the licensee or the applicant has done any of the following:
(a)
Has willfully refused to comply with the laws and regulations relative to nursery stock, or to any pest which might be carried by nursery stock.
(b)
Was intentionally guilty of fraud or deception in the procurement of the license.
(c)
Has been guilty of fraud or misrepresentation in the handling or sale of nursery stock.
(d)
Has failed to maintain nursery stock produced or sold by him in accordance with the standards of cleanliness which are prescribed by the director.
(e)
Has failed to comply with any lawful order which is issued by the director or commissioner.