(1) By or under the supervision of an agency of this state or of the federal government authorized by law to conduct research in the field of pesticides which has a valid experimental permit issued by the commissioner, or
(2) By others having a valid experimental permit issued by the commissioner if the pesticide is not sold and if the container thereof is plainly and conspicuously marked "For experimental use only--Not to be sold," together with the manufacturer's name and address. However, if such a written permit has been obtained from the commissioner, pesticides may be sold for experimental purposes subject to such restrictions and conditions as may be set forth in the permit. 2. No article shall be deemed in violation of this article when intended solely for export to a foreign country, and when prepared or packed according to the specifications or directions of the purchaser. If not so exported, all of the provisions of this article shall apply. 3. Notwithstanding any other provision of this article, registration is not required in the case of a pesticide shipped from one plant within this state to another plant within this state operated by the same person.