§ 169. Delegation of powers and immunities in regard to dutch elm disease in municipalities. The powers and immunities prescribed and granted in sections one hundred sixty-four, one hundred sixty-five and one hundred sixty-seven of this article may, within the limits of any municipality, be exercised and enjoyed by the appropriate officers and employees of such municipality with respect and in regard to the dutch elm disease, if with the approval of the commissioner and under the direction of the commissioner or his representative and if the local legislative body of any such municipality by local law or ordinance elects to exercise and enjoy such powers and immunities.