Farmer perceptions on herbicide resistance and proposed herbicide use to control annual ryegrass in South Australia

Abstract

The relationship between the use of herbicides to control Lolium rigidum and herbicide resistance was investigated by surveying 62 growers with properties located in major South Australian grain growing regions during March and April 2003. These growers have relied heavily on a variety of herbicides with different modes of action for weed management. A high percentage of growers reported resistance to ACCase-inhibiting herbicides and consequently relatively few growers proposed to use aryloxyphenoxypropanoate herbicides in 2003. A high percentage of growers also perceived resistance to chlorsulfuron or triasulfuron and trifluralin. Growers planned to use herbicides with modes of action other than ACCase for the control of L. rigidum. The perceived high resistance status of L. rigidum to ACCase-inhibiting herbicides and ALS-inhibiting herbicides is not unexpected; however, the perceived resistance status of trifluralin is controversial. Perception of trifluralin resistance is apparently influencing weed management. Therefore, further investigation of trifluralin resistance is required.