All matters relating to the organization, discipline and government of the Virginia National Guard, not otherwise provided for by law or by regulations, shall be decided by the custom and usage of the United States army, air force or navy, as appropriate. In addition, all members of the Virginia Defense Force and the unorganized militia on training duty or state active duty shall be subject to military discipline. Infractions of military discipline for the Virginia National Guard shall be punishable under the provisions of §§ 44-40 and 44-40.01 and Article 4 (§ 44-42 et seq.). Infractions of military discipline for the Virginia Defense Force and unorganized militia shall be punishable under the provisions of §§ 44-40 and 44-40.01.