NON-CROP WEED MANAGEMENT

Matthew Schuster

Minidoka County Extension Educator

Weed management in non-crop areas is just as important as weed management within your crop. In fact, maintaining effective control along your field borders, ditch banks, range land, etc. is a critical component of long-term management since these areas serve as source of seed that infests your field.

Adequate preparation is needed to achieve long-term control in non-crop areas. Fortunately, integrated weed management strategies developed for your cropping system can be directly applied to non-crop areas.

Prevention, Cultural, and Mechanical Control: Start by identifying the primary weed(s) in order to develop a plan to prevent future establishment. Next, understanding the biology of the weed species your trying to manage. Just like understanding how your crop(s) develops results in better yields, understanding the how the weed species grows and develops helps you achieve better management results.

By understanding how the weed species develops you will know the weed’s most vulnerable growth stages, which will dictate your weed management strategy. For example, the success of mowing to prevent seed production, screens in water-ways to prevent seed dissemination, burning to prevent weed movement (such as kochia and Russian thistle) into your fields, or working with your neighbors to prevent weed and weed seed movement all depends on the weeds growth stage, as well as the impact the chosen management strategy has on that growth stage. Seed may still mature if the weed is mowed to late, screens will be useless if the seed is extremely small, and burning an immature perennial weed may or may not have any impact at all.

A long-term management strategy should also include the establishment of perennial grasses. The establishment of these grasses may not happen in one season but they should be the focus of your management plan. Beneficial plants compete against the weeds, robbing them of water, nutrients, and space, and eventually dominate the sight preventing the weed species from establishing. Bare ground is necessary in some cases; however, weeds will have a much better chance establishing if there is no competition.

Biological and Chemical Control: Biological control may or may not fit into your management strategy but they are worth considering. Biological controls take time to establish but if they do they will keep the weed population in check.

Chemical control can play an important role while you are establishing your perennial grasses. However, much like prevention, cultural, and mechanical controls, understanding the biology of the weed will help you achieve better results.

The timing of the herbicide application depends on whether you’re managing an annual or perennial weed. In addition, the area you’re managing, as well as any beneficial plant species present, will be a factor when choosing the brand of herbicide.

Fortunately, there are a number of herbicides labeled for non-crop areas that provide both selective and non-selective control depending on your objectives. I recommend determining your goals and objectives first, then choosing the specific herbicide.

The Pacific Northwest Weed Control Handbook (http://weeds.ippc.orst.edu/pnw/weeds) is a good resource to help screen and select the right herbicide. Your county weed superintendent, fieldman, or myself can also provide assistance.

As with any pesticide, read the label prior to application to determine where the herbicide can be applied, the proper application timing and how it will impact your beneficial plant species and/or crops, as well as any application restrictions.

Long-term control should be the objective of any weed management plan. However, patience is required. Successful long-term strategies take time but are worth the wait. Not only will you reduce the weed pressure but you should also be able to transition from an intensive weed control program to a low maintenance program that keeps the weeds in check.