Published online by Cambridge University Press: 12 June 2017
The movement of biologically active levels of bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4) 3H-one 2,2-dioxide] was followed by monitoring photosynthetic activity of plant parts after application of the herbicide. Bentazon was applied to roots, stems, petioles, portions of the canopy, and portions of individual leaves of 4- to 24-day-old common cocklebur (Xanthium pensylvanicum Wallr.) at rates comparable to field application rates. Application of bentazon anywhere on the plant either slowed or stopped photosynthesis in leaves acropetal to the point of application. Contact of bentazon with stems, petioles or roots contributed to the phytotoxicity of the herbicide.