A pesticide is adulterated in any of the following cases:
(a) Its strength or purity falls below the standard or quality that it is represented to have.
(b) Any ingredient that is necessary to its effectiveness has been wholly or in part abstracted or omitted in its manufacture, or other materials substituted for that ingredient.
(c) It is intended for use on vegetation and contains any substance that is seriously injurious to vegetation, except weeds, if used according to the directions that are furnished with it.