Jointed goatgrass (Aegilops cylindrica Host) is an invasive grass weed that is closely related to wheat. Research has shown that wheat infested with as few as 18 jointed goatgrass plants per square yard can suffer a yield reduction of nearly 30 percent. Problems with jointed goatgrass typically increase as producers adopt conservation tillage or no-till systems, unless these systems include rotation to crops other than winter wheat.
If left uncontrolled, jointed goatgrass will eventually choke out wheat, reducing wheat yields in parts of a field to zero. In addition to yield losses, wheat contaminated with jointed goatgrass will be discounted for dockage when it is delivered to an elevator. Jointed goatgrass in the wheat may also be counted as foreign material, resulting in additional discounts. If contamination is high enough to cause a grade loss there will be still further discounts.
The purpose of this bulletin is to help wheat producers avoid such economic losses by providing information on Best Management Practices for the control of jointed goatgrass in winter wheat. The practices described in this bulletin are intended for dryland continuous-crop wheat producers in the southern Great Plains. This includes the regions of Oklahoma and south-central Kansas where continuous winter wheat is the predominant crop.
Information on jointed goatgrass control for summer fallow wheat producers can be found in “Jointed Goatgrass, Best Management Practices, Central Great Plains” (Washington State University EB2033E) available at www.jointedgoatgrass.wsu.edu or from university Extension specialists.
Introduction to a Multi-practice Approach for Jointed Goatgrass Control
Producers have several practices to choose from for jointed goatgrass control. All of these practices require prior planning, as opposed to waiting until jointed goatgrass has infested a wheat crop and then trying to salvage the crop. Use of a single practice may provide acceptable control in a particular year, but is not likely to be dependable year after year because of varying rainfall and different rates of jointed goatgrass emergence between years.
To successfully control jointed goatgrass and other problem weeds, producers should use a multi-practice approach. Using this system, a producer combines a number of management practices to achieve better weed control than could be obtained by relying on only one practice.
A checklist of possible practices is provided below to show the options that are available for the control of jointed goatgrass. Often, these same practices will help control other grass weeds such as cheat and volunteer rye. In addition, many of these practices will increase wheat production and profitability.
Since many management practices are most appropriate at a specific time during the year, this bulletin discusses them in a timeline arrangement. This timeline begins at wheat harvest, the point at which many producers first notice a jointed goatgrass infestation, and then progresses through the cropping cycle. However, producers should review the entire sequence, as successful use of a given practice may depend on the use of other practices earlier or later in the cropping cycle.
DOLLAR LOSSES FROM FAILURE TO CONTROL JOINTED GOATGRASS CAN BE SEVERE! NOTE THIS EXAMPLE!
If a producer delivers a 1000-bushel load of wheat that contains 3% dockage from jointed goatgrass, it is reasonable to assume that the field suffered a 15% yield loss as a result of the jointed goatgrass infestation. With a 3% dockage discount of 18 cents per bushel, and additional foreign matter and grade discounts (caused by the jointed goatgrass contamination) of up to 18 cents per bushel, the producer lost $360.00 (1000 bu x $0.36/bu) from discounts. In addition, at $6.00/bu wheat, $900.00 was lost from reduced production (1000 bu x 15% yield loss x $6.00/bu).
JOINTED GOATGRASS COST THIS PRODUCER OVER $1250.00 ON JUST ONE TRUCKLOAD!
If the producer harvested 20,000 bushels of similar wheat, total losses would be over $25,000. At higher wheat prices, losses are even greater. For every $1.00/bu increase in the price of wheat, losses from the above example would increase more than $150.00 per load.