Susceptibility of Various Crop and Weed Species to AAL-Toxin, a Natural Herbicide

AAL-toxin, produced byAlternaria alternata, was investigated for its phytotoxic effects on 86 crop and weed species. On susceptible tomato leaf discs, AAL-toxin caused electrolyte leakage and chlorosis at 0.01 μM in 24 h. Plants tested exhibited a range of response. AAL-toxin damaged sensitive plants at 5 μM while other plants showed minimal damage at > 1000 μM. Cotton and the important weeds, Canada thistle, field bindweed, and velvetleaf were largely unaffected. Monocots tested were largely immune.