Jointed goatgrass (Aegilops cylindrica Host) is an invasive weed that causes serious problems in winter wheat in the western United States. Jointed goatgrass reduces wheat yield by competing with wheat for sunlight, soil moisture, and soil nutrients. It is an especially good competitor under conditions of stress such as drought. 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%. If not controlled, jointed goatgrass will eventually choke out wheat, reducing wheat yields to zero in parts of the field.
In addition to yield losses, wheat contaminated with jointed goatgrass will be discounted for dockage when it is delivered to an elevator. Typical discounts are 4¢/bushel at 1% dockage, 11¢/bushel at 2% dockage, and 18¢/bushel at 3% dockage.
This bulletin will 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 wheat producers in the western part of the Central Great Plains. This includes producers in areas of western Kansas, eastern Colorado, western and southwestern Nebraska, and southeastern Wyoming, where the predominant dryland cropping systems are winter wheat–fallow, or winter wheat–spring planted crop–fallow.
Introduction to a Multi-Practice Approach for Jointed Goatgrass Management
Producers have many control practices to choose from when managing jointed goatgrass. However, seldom will a single practice provide acceptable control, especially over a number of years. Effectiveness varies because of such things as drastic differences in weather and differing rates of jointed goatgrass emergence between years. To successfully control jointed goatgrass and other problem weeds, producers should use a multi-practice approach in which a producer combines a number of management practices to achieve better weed control than could be obtained by relying on only one or two practices.
A checklist of possible practices is provided below to show producers numerous options that are available for the control of jointed goatgrass. Often, these same practices can also be used to control other grass weeds such as downy brome and volunteer rye. 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 progresses through the cropping cycle. Producers should review the entire sequence, however, 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!
EXAMPLE: A producer delivers a 1000 bushel load of wheat that contains 3% dockage from jointed goatgrass. If grain from a field contains 3% jointed goatgrass, it is reasonable to assume that the field suffered a 15% yield loss as a result of the jointed goatgrass infestation. At a wheat price of $6.00 per bushel, with the dockage discounts listed above, this producer lost $180.00 from dockage discounts (1000bu x $0.18/bu) and $900.00 from lost production (1000bu x 15% yield loss x $6.00/bu). Jointed goatgrass cost this producer over $1000.00 on just one truckload. If the producer harvested 20,000 bushels of similar wheat, total losses would be over $21,000. At higher wheat prices the losses will be even greater.