Herbicides for irrigation ditch banks

By Barry Tickes, UA Area Agriculture Agent

Weeds are a problem year after year even where diligently controlled. A major reason is that weed seeds continually move into fields by irrigation water, wind, equipment, contaminated seed, and other means.

Controlling weeds on irrigation ditch banks can greatly help reduce weed seed movement into fields.

The Environmental Protection Agency regards “non-crop” areas as those not dedicated to crop production. Although crops are not normally grown on irrigation ditch banks, these areas should not be managed as non-crop.

Several very broad spectrum and long lasting herbicides are registered for “non-crop” areas which include roadsides, industrial sites, fence rows, around structures, and railroads. Irrigation ditch banks should be considered separately due to the proximity to crop fields and irrigation water and the potential for herbicide movement into sensitive areas.

It is important to read the label carefully and only use products specifically allowed for use on “ditch banks.” Some products are restricted to drainage ditch banks or dry ditches. Some can be used only above the water line. Some can only be used for non-irrigation ditch banks. Since most ditches in the Yuma area are used for irrigation, this can be confusing.

The definition of a ditch can include an open trench or natural channel. It can also include ditches not in use for long periods of time.

Some labels specify how long this non-use period should be. Click on this link for a list of the Herbicides Registered For Irrigation Ditch Banks in Arizona. It has those that can only be used on drainage ditches or dry ditches and if the products have soil residual or foliar activity. It does not include several available premixes.

Contact Tickes: (928) 580-9902 or btickes@ag.arizona.edu.

Future meetings

Southwest Ag Summit - March 9-10, 2011.

For more information, call the Yuma County Cooperative Extension Office at 928-726-3904 or go online to http://swagsummit.com/event_schedule.html.