Published on 23/04/2020
Containing 500 grams per litre of 2,4-DB dimethylamine salt (Group O1), the phenoxy herbicide was introduced to meet market demand, and registered just before Christmas. It joins Valdo 800WG, Kyte 700WG and Dictate 480 to extend the company’s range of foliar selective products available for lucerne.
Cynthia Christie, Nufarm technical specialist, says as well as both new and established lucerne, Debut is also approved for control of broadleaf weeds in new pasture.
Labelled weeds include annual buttercups, cresses, fathen, hedge mustard, plantains, red root, shepherd’s purse, annual thistles, ragwort, docks and wireweed. With lucerne continuing to fill a valuable feed niche on many farms, both irrigated and dryland growers have become increasingly aware of the importance of good husbandry in maintaining the productive life of their stands,
Christie says. “Lucerne’s a really useful crop in many respects, but one thing it won’t tolerate is weed competition.“ All 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, however, usually comes down to the level of weed control from establishment onwards. “Keeping weeds out from the start can add years to the life of a stand, not to mention maintaining high forage quality.” Weeds can also harbour insect pests.
The active ingredient in Debut, 2,4-DB, is an inactive form of the phenoxy molecule, and after spraying onto weeds, it must first be converted into 2,4-D, then into the active 2,4-D acid. For this reason, Debut is best applied when weeds are small and actively growing, Christie says.
Timing is important for crop safety – newly sown lucerne sprayed post emergence must have at least one, or preferably two, trifoliate leaves before application, and the same applies to young clover plants in new pasture. Where ground cover is less than 50 per cent, she advises growers to wait until there’s more vegetation, to reduce the possibilities of Debut being absorbed into the roots of the crop.
For established lucerne, growers should heavy graze prior to application to remove leaf tissue and minimise crop suppression.
Label application rates are 4.8-6.4 litres per ha, and the withholding period is one day, although Christie notes that poisonous plants like ragwort and tutu may become more palatable after spraying, meaning livestock should be kept away until they’ve died down.
Debut can be tank mixed with Dictate 480 to extend the range of weed species controlled, and can be applied using conventional ground or aerial spray equipment.
It comes in 20-litre packs and qualifies for Agrecovery.
For more detail contact your Nufarm territory manager