The role of imidazolinone herbicides for the control of Bromus rigidus (rigid brome) in wheat in southern Australia

摘要

Five field experiments were undertaken over a three-year period in South Australia to investigate the efficacy of imidazolinone herbicides for the control of rigid brome in imidazolinone-tolerant wheat (Clearfield(TM), CLF). Imidazolinone herbicides, imazapyr, imazapyr plus imazapic and imazapyr plus imazamox applied post-emergence to imi-wheat (cvs. CLF-Janz and CLF-Stiletto) at the four-leaf stage, provided consistent and high levels of rigid brome control (>=87%). In contrast, applications of the alternative herbicide mesosulfuron-methyl (post-emergence) provided limited and variable control of rigid brome (11-67%). Furthermore, imidazolinone treatments caused a large reduction (P<0.05) in rigid brome seed production (@?6 seedsm^-^2) as compared to mesosulfuron-methyl (461-3983 seedsm^-^2) and the non-treated control (2257-11@?865 seedsm^-^2). Imazapyr plus imazapic provided consistent control of rigid brome and resulted in higher grain yields (28-45%) than wheat treated with mesosulfuron-methyl. Based on these results post-emergence applications of imazapyr, imazapyr plus imazapic and imazapyr plus imazamox to imi-wheat could play an important role in the management of rigid brome in southern Australia. However, the effect of these herbicides on existing and new cultivars of imi-wheat (multiple-gene resistance) and issues concerning persistence in low rainfall environments and crop damage on sandy soils require attention.