Getting spraying right
The most common herbicides to use contain MCPA® Amine or 2,4-D Amine 625 as the active ingredient. In sub-clover based pastures, MCPA® Amine is preferred. In white clover or sub-clover/white clover pastures 2,4-D Amine is recommended. MCPA® Amine and 2,4-D Amine can be used on balansa and Persian clover.
Other clovers vary in their tolerance to both herbicides, both between species and between cultivars within the same species. For specific advice on cultivar tolerance, contact the herbicide supplier.
MCPA® Amine and 2,4-D Amine are phenoxy herbicides (Group 1), which act like a growth hormone causing rapid cell division. At high rates, uncontrollable growth occurs, causing death. At lower rates, the herbicide stimulates cell division, making the plant grow more upright.
The plants respond by temporarily drawing sugars from the roots and crown into the leaves. The herbicide makes the plant more palatable and more accessible for grazing, while depleting the reserves the plant uses after grazing to regrow new leaves.
The effect only lasts about two weeks, after which the reserves slowly return to the root system, even though the plant may still look deformed.
Unsprayed capeweed (left) and sprayed capeweed (middle and right) showing distorted leaves and upright growth.