(a) The following are designated as commercial citrus-producing areas:

(b) The list in paragraph (a) of this section is intended to include jurisdictions which have commercial citrus-producing areas. Less than an entire State may be designated as a commercial citrus-producing area only if the Administrator determines that the area not included as a commercial citrus-producing area does not contain commercial citrus plantings; that the State has adopted and is enforcing a prohibition on the intrastate movement from areas not designated as commercial citrus-producing areas to commercial citrus-producing areas of fruit which are designated as regulated articles and which were moved interstate from a quarantined State pursuant to a limited permit; and that the designation of less than the entire State as a commercial citrus-producing area will otherwise be adequate to prevent the interstate spread of citrus canker.