Inhibition of Velvetleaf (Abutilon tbeopbrasti) Germination and Growth by Benzyl Isothiocyanate, a Natural Toxicant'

Benzyl isothiocyanate (BITC) was extracted from mature papaya (Carica papaya L.) seeds and applied to im- bibed velvetleaf (Abutilon theopbrasti Medic. #3 ABUTH) seeds. Complete inhibition of germination occurred at a concentration of 6 x 10-4 M BITC, and only 28% (compared to controls) of the seeds germinated after 4 days exposure to the 4 x 10-4 M treatment. Corn (Zea mays L. 'DeKalb XL-66') was unaffected even at higher concentrations; how- ever, 72% of imbibed soybeans (Glycine max (L.) Merr. 'Tiger') germinated in 6 x 10-4 M BITC. When this natural inhibitor was applied to etiolated velvetleaf seedlings at 4 x l0-4 M, 100% died in 2 days.