The Inhibition of Axillary and Terminal Bud Growth on Tobacco by a Series of C₂ to C₁₀ Diol Formulations

A series of straight chain or n-diols were evaluated as aqueous emulsions for their ability tO inhibit terminal or axillary bud growth of tobacco plants. These n-C₂ to n-C₁₀ diol formulations (hydroxyls at terminal carbons) were considerably less active than formulations of straight chain alcohols of the same carbon lengths. Shifting the position of the hydroxyls from the terminal carbons changed activity only slighdy. The straight chain diols with 5, 6 or 7 carbons were more active than shorter or longer chain lengths. The efficacy of 1,6-hexanediol was increased when it was formulated with a surfactant having a lOw hydrophilic-lipophilic balance value (11.6 vs. 16.3) so that its effectiveness was similar to that of the n-C₈ plus n-C₁₀ alcohol formulation. Of several substituted diolș evaluated, 2-ethyl- 1,3-hexanediol was the· most active but it caused severe damage to mature leaves thus it is not considered to be a selective plant growth inhibitor. Both 2,5-dimethyl- 2,5-hexanediol and 1,4-cyclohexanediol caused a general growth retardation rather than tissue kill