Published on 23/11/2023
Spring sown forage crops are a perfect example. The last thing farmers want in their brassicas, fodder beet and/or chicory is a lot of low nutritional value grass species which do not contribute to dry matter yield.
Annual poa, couch, barley grass, bristlegrass, brown top, ryegrass and brome –among others – compete with newly-sown seedlings for space, light and nutrients, potentially suppressing crop dry matter and plant population.
But there’s another equally important reason to control them: They compete with the new pasture which usually follows forage crops.
“Once new pastures are sown, farmers do not have an opportunity to control undesirable grass species,” points out Nufarm technical specialist Sonja Vreugdenhil.
Yet the presence of such low quality grasses is a major reason for renewing pastures in the first place. So controlling unwanted grass in the early stages of forage crop establishment is doubly beneficial, for both the sake of the crop itself, and the long-term persistence and performance of pasture sown subsequently.
Her advice? Encourage farmers to spray out any grass weeds as early as possible. Grass weeds should have five to 10 cm of leaf at spraying and grass herbicide applied prior to canopy closure.
“Every day they hold off applying a grass herbicide, it can be reducing yield. If you are going to put a crop in, you need to look after it, or you will be disappointed when it comes to grazing.”
One selective post-emergence grass weed herbicide has the benefit of being registered for many spring-sown forage crops – fodder and sugar beet, forage brassicas, chicory, plantain, as well as lucerne, clovers and other legumes.
SeQuence contains the active ingredient clethodim (MOA Group 1) and is registered on 22 grass weeds, including ryegrasses, annual summer grasses, wild oats, cultivated couch and annual poa.
Best results come from applying SeQuence when target grasses are actively growing. This only happens when soil moisture and temperature are at the right level to support growth, so it pays to be aware of how conditions are shaping up at the start of the sea-son.
“Farmers need to do their weed control when the grasses are actively growing. With El Nino predicted this year, for example, we know there’s a chance of hot, dry conditions in some regions. Ryegrass growth slows when temperatures exceed 25°C, paired with dry conditions, the heat of summer may not be the ideal time for controlling it,” Vreugdenhil says.
Likewise it’s important farmers use the correct label rates for the grass weed(s) present, and target plants are the right size for SeQuence to be most effective. SeQuence has a one hour rainfast period.
Grazing withholding periods for SeQuence are three weeks for legume crops, forage herbs and forage brassicas; and nine weeks for fodder and sugar beet.
SeQuence must always be ap-plied with Bonza Gold and maybe tank mixed with Archer or Prestige if broadleaf weed control is also required in forage brassicas. Attack may be added to SeQuence when pest control is needed.
SeQuence is also registered for use in lucerne and now is a good time for farmers to follow up their winter weed control programme in these stands, Sonja Vreugdenhil says.
“Winter sprays will not have removed large grasses, so applying SeQuence in-season will ensure grass weeds are not limiting yield. Lucerne is sensitive to competition from grass, especially in older stands.”
For more detail talk to your local Nufarm territory manager.