Studies were conducted to compare foliar- and root-based absorption and translocation of SC-0051 in corn and soybean using radio-tracer techniques. Visual injury symptoms expressed in soybean by SC-0051 were bleaching in newly formed (meristematic) tissue followed by necrosis. Corn expressed little to no visual injury. SC-0051 was absorbed more rapidly by foliage of corn and soybean than by their roots. Although soybean absorbed more SC-0051 through roots than did corn, there was no difference between species in foliar absorption of SC-0051. SC-0051 was rapidly translocated throughout corn plants but was concentrated mainly in the meristematic tissue of soybean. Even though there were slight differences in absorption and translocation of SC-0051 in corn and soybean, it is likely that differential metabolism of the herbicide explains selectivity.

Nomenclature: SC-0051 (proposed name sulcotrione), 2-[2-chloro-4-(methylsulfonyl)benzoyl]-1,3-cyclohexanedione; corn, Zea mays L ‘Gutwein 69B’; soybean Glycine max (L.) Merr ‘Essex’.

Additional index words: Bleaching herbicides, radiolabeled herbicides, triketone herbicides.

Abbreviations: HAT, hours after treatment; POST, postemergence; PRE, preemergence.