Regulation of the natural growth or development of plants with 2-sulfinyl or 2-sulfonyl pyridine N-oxide compounds

A method of regulating the natural growth or development of plants which comprises applying to said plants an effective non-herbicidal plant-regulating amount of a 2-sulfinyl-, or 2-sulfonyl-pyridine N-oxide compound of the formula ##STR212## wherein:

• n is 1 or 2;
• R.sub.1 is hydrogen, C.sub.1 to C.sub.15 alkyl, phenyl or benzyl;
• R.sub.2 is hydrogen,
• C.sub.1 to C.sub.12 alkyl,
• C.sub.1 to C.sub.4 alkenyl,
• C.sub.2 or C.sub.3 alkoxycarbonyl,
• C.sub.5 or C.sub.6 alicyclic,
• phenyl provided R.sub.1 is not phenyl,
• phenyl substituted with from 1 to 3 substituents which may be the same or different and are selected from the group consisting of C.sub.1 to C.sub.3 alkyl, halogen, cyano, nitro, C.sub.1 or C.sub.2 alkoxy, phenoxy, dioxymethylene and 2,2-dichlorocyclopropyl;
• and phenyl substituted with 4 to 5 substituents which may be the same or different and are selected from methyl and chlorine;
• 1-methyl-2,2-dichlorocyclopropyl,
• 2,2-dichlorocyclopropyl,
• naphthyl, 9-anthryl, 5-indanyl,
• 4-biphenylyl,
• 2-benzothiazolyl, 2-thienyl or benzyl;
• R.sub.1 and R.sub.2 may be joined together in the form of a polymethylene chain --(CH.sub.2).sub.m -where m is 3,4 or 5 to form a carbocyclic ring;
• and when R.sub.1 is hydrogen or methyl R.sub.2 can be the radical ##STR213## where y is 0, 1 or 2 and the X's are the same or different and are selected from C.sub.1 to C.sub.3 alkyl, halogen, and 2,2-dichlorocyclopropyl.