The board of county commissioners of any county engaging in the control of agricultural pests as defined under the provisions of this chapter may compensate for or provide supplies and authorize a person or persons employed as provided in this act, to control agricultural pests within such county; and any person or persons so authorized is hereby empowered and directed to enter upon any farm, railroad right-of-way, irrigation ditches and rights-of-way, grounds, or premises where there are agricultural pests to ascertain conditions and to control such agricultural pests thereon when the owner or occupant shall neglect or refuse to do so.