Mo. Rev. Stat. § 281.290
In order to avoid confusion resulting from diverse requirements, and to avoid increased costs to the people of this state due to the necessity of complying with such diverse requirements in the manufacture, sale and use of such pesticides, it is desirable that there should be uniformity of requirements throughout the state and between the several states and the federal government relating to such pesticides. To this end, the director is authorized and empowered to cooperate with, and enter into agreements with, the federal government, any other state or agency thereof, any other agency of this state, and any political subdivision of this state regarding pesticide regulatory requirements under sections 281.210 to 281.310 and sections 281.005 to 281.115.
§ 281.290, RSMo