1989 Volume 34 Issue 3 Pages 196-203
Effects of various types of surfactants on the action of the foliar applied type herbicide propanil, especially on the acceleration of its herbicidal action, were evaluated in relation to the physical properties, spreading and permeating properties of the surfactant solutions (0.1%).
The 0.1% solutions of the POE nonylphenyl ether surfactants varied in their spreading and permeating properties in proportion to their HLB values, with the maximum being around 12-13 of the HLB value.
Most of the surfactants added accelerated the propanil action applied at a sub-lethal dosage against barnyard millet (Echinochloa crus-galli L.). The effects on this action were higher at about 12 of HLB or 8 of EO moles in the POE nonylphenyl ether surfactants. In addition, with all the surfactants tested, a better correlation coefficient 0.77 (p<0.1) was obtained between the acceleration-activity and the values calculated as follows: values of spreading property × (1/values of permeating property), indicating that the surfactants which were good in both properties showed higher acceleration-activity.
Effects of three surfactants with different ionic characters on the propanil action were also examined by monitoring the photosynthetic activity of the treated plants. The data showed a similar trend to those in the pot test and the No. 4 surfactant was the most effective, indicating that it accelerated propanil action presumably by improving cuticle penetration of the herbicide.
