More than 90% of kochia populations show resistance to acetolactate synthase (ALS)-inhibiting herbicides, but scientists have worked to outmaneuver the crop-reducing weed.
Kochia, a weed rapidly becoming more abundant across southern Canadian prairies and the Great Plains of the United States, can reduce crop yields by up to 60%. The phenomenon of negative cross-resistance, however, might offer another path to defeating the spread of this weed.
When a plant becomes resistant to one herbicide, other physiological changes might occur that result in increased sensitivity to other herbicide families. The mutated, resistant plant that is more susceptible to the second herbicide is displaying the characteristic of negative cross-resistance.
The current issue of the journal Weed Technology reports on a greenhouse test of kochia plants. Six alternative herbicides were tested on the weed with the resistant mutation. Researchers were looking for differences in the reactions of the resistant kochia compared with the wild plant, which is still susceptible to herbicides. Full text of the article can be found in Weed Technology, Vol. 26, No. 3, July-September 2012, and is available at http://www.wssajournals.org/.
Source: Weed Technology, Edited by FCI Staff