Section 24. The director, either personally or through his assistants, may inspect any orchard, field garden, roadside or other place where trees, shrubs or other plants exist, whether on public or private property, which he may know or have reason to suspect is overgrown with noxious weeds or infested with the San Jose scale or any serious insect pests or plant disease, when in his judgment such pests, disease or weeds are likely to cause loss to adjoining owners, and may serve upon the owner, occupant or person in charge of the land on which such noxious weeds, trees, shrubs or other plants are present, written notice of the presence of such weeds, pests or plant disease, with a statement that they constitute a public nuisance, together with directions to abate the same, giving the methods of treatment for the abatement thereof, and stating a time within which the nuisance must be abated in accordance with the methods given therein. If the person no notified refuses or neglects so to treat or destroy such weeds, trees, shrubs or other plants within the time prescribed, the director may cause such property to be so treated or destroyed, and may employ all necessary assistants for this purpose, who may enter upon any public or private property, if such entry is necessary for this purpose. Upon the completion of said treatment the director shall certify in writing to the owner or person in charge of the treated property the amount of the cost of such treatment, and if this be not paid to the commissioner within ninety days thereafter, the same may be recovered by suit, together with the cost of the suit.