Take no prisoners!
It sounds a little obvious, but annual weeds must set seed if the species is to persist, so stopping weed seed set is a critical strategy to manage herbicide-resistant weeds. Stopping seed set does two things, 1. We reduce the size of the weed seed bank, and 2. It acts as a second knock to clean up survivors to other selective herbicides, preventing resistance evolution and prolonging the life of the selective herbicides.
One comment that you will hear time and time again from successful grain growers is, ‘we never miss an opportunity to stop seed set’. Sure, the opportunity does not always present itself, but when it does we owe it to ourselves to stop seed set at all costs and take no prisoners.
Some of the key seed set control options include:
- Crop top canola, pulses and feed barley (currently under permit) in weedy paddocks;
- Consider hay, brown manure or long fallow in high-pressure paddocks;
- Spray top/spray fallow pasture prior to the cropping phase.
Check out the GRDC’s latest fact sheet on pre-harvest herbicide use (including crop topping) here.