Published online by Cambridge University Press: 12 June 2017
Rates of evaporation of dalapon acid and four low-volatile esters of dalapon from open dishes at 38C. in pounds per acre per hour, determined gravimetrically, were dalapon acid, 180; propyleneglycol bis ester, 27; diethyleneglycol bis ester, 1.6; dipropyleneglycol bis ester, 0.83; and triethyleneglycol bis ester, 0.61. Foliar applications on an acid equivalent basis were phytotoxic to seedling oats in the increasing order of propyleneglycol bis ester, acid, dipropyleneglycol bis ester, diethyleneglycol bis ester, sodium salt, and tripropyleneglycol bis ester. Relative phytotoxicities were not altered by subjecting plants to rapid drying after spraying. These compounds did not differ significantly in phytotoxicity when added to the rooting medium of germinating oat plants. The triethyleneglycol bis ester, and possibly other esters of dalapon, may offer practical advantages as herbicides other than those related to volatility.