An Evaluation of Dimethyl Sulfoxide as a Possible Adjuvant for Several Herbicides

摘要

Dimethyl sulfoxide (DMSO) and Tween 20 were compared as adjuvants for foliar applications of 1,1'-ethylene-2,2'-dipyridylium dibromide (diquat dibromide), 2-methoxy-3,6-dichlorobenzoic acid (dicamba), and 4-amino-3,5,6-trichloropicolinic acid (picloram) to bean plants growing under greenhouse or growth-chamber conditions. Inhibition of growth was the criterion of injury employed in evaluating these data. The effect of a commercial formulation of diquat alone and diquat plus 0.5 or 1.0% DMSO on growth of Red Kidney beans was not significantly different from the control because of the sublethal dose of herbicide applied. However, the addition of 5 or 10% DMSO caused an increase in phytotoxicity that was significantly different from either the control or diquat alone. Diquat plus 50% DMSO (the highest level employed) was the most phytotoxic treatment but it was not significantly different from the 20 and 30% rates of DMSO. Various combinations of 0.5% Tween 20, 30% DMSO, and technical grade picloram (12 micro g per plant) applied to Black Valentine beans showed that both adjuvants significantly increased the effectiveness of picloram. DMSO, however, offered no advantage over Tween 20. (Author)