What options will we have to manage brome once it becomes resistant to Group B herbicides?
The answer to this question being investigated by the Managing Brome in Canola Trial managed by Dr Gurjeet Gill, from the University of Adelaide, and funded by GRDC. The trial is investigating the use of combinations of management practices (time of sowing, variety and sowing density) and herbicide options (Groups A, C and D) to control brome.
“The first time of sowing for this trial, which was sown on 17 April at Whirly (north-east of Birchip), is now up after emerging on the back of the ANZAC Day weekend’s rain.” said Kate Maddern, BCG, “this trial will be comparing two different times of sowing, two different sowing rates, as well as two early-mid maturity varieties, InVigor 4510 (Hybrid) and ATR-Bonito (OP). The earlier date aims to flower in the optimal sowing window for Birchip (26 July), and the later time of sowing in mid-May will hopefully emphasise the yield benefits of sowing the right variety of canola at the right time.”
“It will be interesting to compare the effect of the early vigour of the hybrid variety on weed control compared to the less vigorous OP variety, and if the yield difference between the two is enough to justify the increased seed cost” Kate explained “The two seeding rates will complement BCG’s canola Plant Establishment work while providing a better understanding of the effects of crop competition on brome, and hopefully defining if hybrid seed can be sown at lower rates to minimise seed costs without yield penalty.”
The herbicide treatments that will be used in this trial are:
A knockdown only with atrazine (C) pre-emergent
Atrazine (C) pre-emergent followed by Verdict (A) post-emergent
Atrazine (C) and propyzamide (D) pre-emergent followed by Verdict (A) and atrazine (C) post emergent
These products were selected to highlight the efficacy of the herbicide options available.
While brome is not yet resistant to Group B chemistry, this trial will investigate which tools can be used effectively to take the pressure off group Bs and slow the increase of resistance, as well as looking at what options will be available to farmers if the worst does happen.