Increasing herbicide efficacy on roadways and other common areas

When controlling weeds on roadways and other common areas within the nursery many of us will apply a post emergent herbicide to control existing weeds, and a pre-emergent herbicide to prevent weeds seeds from germinating. "So, if this is your current practice to keep these areas clean I wanted to save you a little bit of frustration and money too", says Nelson Gonzalez of ICL. "If you apply this combination when the weeds are dense and/or tall you may have noticed that you experience poor efficacy from the pre-emergent herbicide. This is due to the fact that in order for a pre-emergent herbicide to control weeds it must land on the bare ground and form a barrier where weeds seeds cannot germinate. A dense canopy of existing weeds will prevent this from occurring."

Whenever you have a densely populated area or tall weeds on roadways, one of the steps you can take to improve the efficacy of the pre-emergent herbicide is to first apply the post emergent to these weedy areas. Then, a couple weeks later when the weeds have died back, come back with a pre-emergent (and possibly a post-emergent) treatment depending on when the last application of post emergent was applied and if there are any existing weeds.

In conclusion, keep in mind that when applying a pre-emergent herbicide, it must land on its intended target, which in this case is the bare ground, and remain undisturbed after application in order to improve the efficacy of the herbicide and provide any decent level of control.

For more information:
ICL Group
Nelson Gonzalez
Nelson.Gonzalez@icl-group.com
www.icl-group.com