Survey of 'Polymeria longifolia' (Lindley) in the Australian cotton industry

The present status and control of polymeria take-all ('Polymeria longifolia' Lindley) in the Australian cotton industry was assessed in a survey involving the 96 cotton consultants and farm agronomists in New South Wales (NSW) and southern and central Queensland (Qld) at the start of the 1996/97 growing season. The survey aimed to draw together much of the anecdotal information that existed about the weed and to use this information to direct future research needs. A response rate of 62.5°A) was achieved indicating that the survey technique was successful and that there was real concern about the impact of this weed. The areas of greatest concern for polymeria take-all were the Gwydir, Namoi and Macintyre Valleys and the St. George area. Overall, even though infestations occurred in only 1% of the area surveyed, it was believed to be the fourth worst weed in cotton crops, being difficult to control and causing large yield reductions by removing moisture from the soil. The additional cost of treatment of polymeria take-all ranged from $12 to $100 ha⁻¹ y⁻¹. Herbicide application was regarded as the most successful means of control but it resulted in a decrease in the occurrence of the weed in only 37% of cases and all herbicides registered for in-crop use in non-herbicide resistant cotton were ineffective.