Farmers looking to optimise the longevity and yield of high-value lucerne stands have a new weed control option available this season.
Chateau® herbicide from Nufarm has recently been registered for contact and residual weed control in established lucerne of at least 12 months old, meaning it can be incorporated into this year’s lucerne maintenance spray programme if required.
Nufarm Technical Specialist Paul Addison says both irrigated and dryland growers are increasingly aware of the importance of good crop husbandry, particularly weed control, 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 is a useful crop in many respects and continues to fill a valuable feed niche on many farms. But one thing it will not tolerate is competition from weeds,” he says.
All lucerne stands need to be renewed at some stage as 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,” Paul says.
Chateau is primarily a soil residual herbicide but does provide some contact activity on seedling broadleaf weeds at 2 to 6 leaf stage. It is important to add a knockdown herbicide for control of established weeds, particularly grasses.
Applied in late autumn or winter, Chateau will control weeds for two to four months, including key species such as hawksbeard, horehound and dandelion.
Nufarm trials¹ show Chateau (Group 14) is a suitable replacement for atrazine (Group 5) in the annual clean-up spray applied during lucerne dormancy. Paul says this is because it provides a longer period of control and covers a wider weed spectrum.
“It is best to apply Chateau soon after grazing or cutting so that the lucerne’s foliage is not shading the soil or the emerged weeds,” he adds.
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.
A recommended tank mix partner herbicide is Gramoxone 250 for mixed broadleaf and grassweed populations and where broadleaf weeds are established.
Sprayed lucerne cannot be grazed or cut for stock food for 28 days after application.
For further advice on keeping your lucerne thriving this season, contact your local PGG Wrightson Technical Field Representative.
SUPPLIED BY NUFARM
1 Chateau® herbicide trials in lucerne conducted in New Zealand between 2017 and 2019: NUNZ1721; NUNZ1722; NUNZ1726 and NUNZ1909.
Registered pursuant to ACVM Act 1997, Chateau #P009507. Always read the registered label before use.
