The toxicity of oil herbicides to Paspalum dilatatum Poir.: Effect of composition of the oil

Abstract

Hydrocarbon oils of varying boiling range and percentage "aromatic" fraction were tested for their toxicity to Paspalum dilatatum in the field and glass-house.Contact injury and final toxicity are separate phenomena and are controlled by different factors. The contact effect of oil herbicides depended on the proportion of aromatic fraction in the oil. The minimum percentage of aromatics required to produce rapid contact injury increases with increasing boiling-point of the oil. Mid boiling-point was shown to be an important and consistent factor in oil toxicity as measured by regrowth. Oil toxicity increases with mid boiling point of the oil. Toxicity in the field decreases with increasing aromatics. In the glasshouse the reverse is the case.