Herbicide Resistant Weeds

Responses of Xanthium strumarium populations to sublethal applications of bentazone.

Zhang, J., P. B. Cavers, and M. Jasieniuk. 1994. Responses of Xanthium strumarium populations to sublethal applications of bentazone. Weed Research. 34: 55-61.

The responses of 10 natural or agricultural populations of X. strumarium, collected from different sites in SW Ontario during Oct. 1989, to sublethal concn of post-em. bentazone (0.25- and 0.5-fold the recommended rate of 1080 g/ha) were examined under field conditions on silt loam 10 km N. of London, Ontario, in spring-summer 1990. Both the vegetative growth and the reproduction of sprayed plants were affected by the herbicide. Some populations were more tolerant of bentazone than others, but the degree of herbicide tolerance did not depend on the previous herbicide experience of a population. Bentazone treatment significantly reduced the fruit wt in some populations, which in turn could affect the survival and growth of subsequent seedlings.