It is often said that weed control is a numbers game. Once weeds start to multiply, so do the problems in controlling them.
One of the key strategies for managing resistance is to reduce the size of the weed seed bank. Fewer seeds with the potential to germinate means fewer to control once they start to emerge and lower selection pressure for herbicide resistance.
Once the weed pressure is reduced, each weed control technique you use is more likely to provide good results. Less density makes it easier to achieve better spray coverage, and late germinations are less likely to cause major problems.
Tools for managing herbicide resistance are not just limited to managing herbicide applications and rotating herbicide mode of action (MOA) groups. Non-chemical control tactics you can try include:
Phytosanitary measures such as equipment sanitation, clean seed and managing weed seeds at harvest with a chaff cart.
Consult your advisor on other non-chemical and rotational tools that can be applied in your specific farming system. The Weedsmart website provides good advice in this area.
Aim to achieve the best possible weed control before crop emergence by using:
To significantly reduce the weed seed bank, investing in that higher level of pre-emergent weed control will pay off – usually by reducing the requirement for a post-emergent grass weed herbicide application as well as increasing yield. Doing so will also allow you to preserve herbicides such as trifluralin for use in other crops within the wheat rotation, such as canola or grain legumes.