Factors Affecting Growth-Regulator Herbicide Volatility Available to Purchase

Numerous factors can affect the volatility of growth-regulator herbicides. At the time of herbicide application a percentage of the spray may be deposited on soil and a percentage on plant foliage. Herbicide volatility was evaluated with a tomato bioassay in which the herbicide was applied to bare soil or to wheat. Maximum tomato injury from dicamba volatility was observed 14 days after initial exposure. Adjuvants in the spray solution could increase or decrease herbicide volatility. The diglycolamine salt of dicamba was applied to two different soils in greenhouse studies. Volatility differences from the soil types tested were not observed. Foliarly applied adjuvants that increased dicamba activity in the field, when applied to bare soil, appeared to increase dicamba volatility.