Published on 28/04/2023
Chateau herbicide from Nufarm has recently been registered for contact and residual weed control in established lucerne (at least 12 months old), meaning it can be incorporated into this year’s lucerne maintenance spray programme if required.
Applied in late autumn or winter, Chateau will control weeds for two to four months, including key species such as hawksbeard, horehound and dandelion.
Chateau is primarily a soil residual herbicide, but does provide some contact activity on seedling broadleaf weeds (two to six leaf), so a knockdown herbicide must be added for control of established weeds, particularly grasses.
Nufarm technical manager Paul Addison says trials have shown Chateau (Group 14) is an ideal replacement for atrazine (Group 5) in the annual clean-up spray applied during lucerne dormancy, because it provides a longer period of control and covers a wider weed spectrum.
“It’s best to apply Chateau soon after grazing or cutting, so that lucerne foliage is not shading the soil or emerged weeds,” he adds.
Addison says both irrigated and dryland growers are increasingly aware of the importance of good crop husbandry in maintaining the productive life of their lucerne stands. Well-established and maintained Lucerne can produce significant amounts of high-quality feed for many years.
“It’s a really useful crop in many respects and continues to fill a valuable feed niche on many farms. But one thing it won’t tolerate is competition from weeds,” he says.
All lucerne stands need to be renewed at some stage because the plants are self-thinning.
“The difference between having to spray out and replace the stand sooner rather than later often comes down to the level of weed control from establishment onwards. Keeping weeds out can add years to the life of a Lucerne stand, not to mention maintaining high forage quality,” Addison says.
The herbicide should not be applied to lucerne with more than 15 cm of growth, nor should it be used on mixed lucerne-grass or other lucerne-pasture stands. Because it has residual action, farmers should also avoid using it where over-sowing or renovation of Lucerne is intended.
Recommended tank mix partner herbicides are Gramoxone 250, for mixed broadleaf and grassweed populations and where broad-leaf weeds are established; and SeQuence + Bonza Gold where grassweeds dominate and where there are few emerged broadleaf weeds.
Sprayed lucerne cannot be grazed or cut for stock food for 28 days after application.
For more detail contact your local Nufarm territory manager.