Rapid Spread of Resistant Weeds
CHANGES TO WEED CONTROL
Having farmers aware that there are resistant weeds in their fields or their neighbors’ fields that will probably invade their fields eventually leads to the switching of different herbicide programs, of which there is at least one per crop protection company offered as a solution or partial solution. Methods can also include mechanical control and hand weeding that went by the wayside in recent years.
Smith is a proponent of helping plants fight for their share of light, nutrients and water in low-level weed infestations and notes that the use of multiple modes of action herbicide programs put stress on the crop plants.
He notes that stress mitigation is important because the plant has to metabolize each herbicide molecule into a non-toxic form.
“In so doing, it takes resources within the plant that may manifest itself in a transient nutrient deficiency such as manganese or zinc … But this can be overcome through the use of micronutrients along with the herbicide spray,” Smith said.
He noted the problem with resistant weeds in a nutshell. “It is not like a resistant weed turns bright red and says here I am. It takes a lot of vigilance on the part of the growers, crop advisors and Extension service to identify resistant weeds.”