Iowa Admin. Code r. 21-45.9
Directions for use are required whenever they are necessary for the protection of the public. The public includes not only users of pesticides but also those who handle them or may be affected by their use, handling, or storage. Directions for use are considered necessary in the case of most small retail containers which go into the hands of users, and in the case of larger containers with the following exception:
Directions may be omitted if the pesticide is to be used by manufacturers in their regular manufacturing processes; provided, the label clearly shows that the product is intended for use only in manufacturing processes and bears an ingredient statement giving the name and percentage of each of the active ingredients.
Iowa Admin. Code r. 21-45.9