Farmers know that Capeweed, Arctotheca calendula, and erodium spp are tough competitors with desirable clover and pasture grasses. Control measures such as spray grazing with Thistlekillem [MCPA amine] are effective if those weeds are controlled early and grazing management is good.
Agtryne MA offers greater flexibility and robustness in that it can control more mature weeds and is not so dependent on grazing pressure afterwards. It is also more effective on Erodium.
Erodium seedheads can cause serious damage to livestock in spring.
Agtryne MA contains terbutryn at 275g/L and MCPA at 160g/L.
Agtryne MA is increasingly useful in higher rainfall areas because it gives excellent cost effective control of not only important weeds such as Capeweed, erodium species but also Toadrush, Patersons curse and Fumitory.
Getting the Best out of Agtryne MA
Timing
The normal timing is to spray in early to mid winter by which time most of the seeds have germinated. Even though Agtryne is robust, several seasons of trials have shown best weed control resulted from spraying young weeds while they are less competitive with the pasture. The clover should have at least three trifoliate leaves.
Rates
Use a rate of 1 L/ha for weeds up to 7 cm diameter and 1.5 L/ha for plants up to 20 cm diameter. Include one of the compatible insecticides if required. Do not add a wetting agent or spraying oil Other pasture weeds labeled for control by the 1 - 1.5 L/ha rates of Agtryne MA are Patersons curse, Crassula, and Toad rush.
Spray volumes
Use spray volumes of 50 to 100 L/ha for ground application and 20 to 30 L/ha for aerial application (30 L/ha from the air is preferred for more reliable results). Apply the higher volume if weeds are dense or pasture cover is thick
Understanding the effect of Agtryne MA® on desirable species.
Farmers and agronomists note that, on occasions, Agtryne MA has an effect on non target clovers, cereal crops, and young grasses. Many weed free trials confirm that this does not usually affect yield. [See Figures 1 & 2] If a growth check occurs a full recovery can normally be expected. Understanding the circumstances under which crop effect may occur can help to minimise farmer concerns.
- Stress
Plants under stress such as waterlogging, dry soils, prolonged cloudy weather can be affected by terbutryn because the metabolic processes in the desirable plant are reduced by the stress and the plant is unable to detoxify as much terbutryn.
- High light intensity and temperature
High light intensity and high temperatures both increase the degree and rapidity of injury from terbutryn. Hence the label requirement not to spray if the ambient temperature exceeds 18° C That is, the temperature on the day before spraying, the day of spraying and for four days after spraying should be below 18° C
- Plant size and state
Young grasses, clovers and cereal plants cannot metabolise terbutryn as well as more mature plants. Also plants that are ‘soft’ i.e. have not gone through a period of frost, are more susceptible. The label states that 3 true leaves is the earliest stage for spraying Agtryne MA onto grasses and cereals.
Sub clovers must be at least 3 true leaves and white clover must be at least 5 true leaves. These are minimums; err on the side of caution with desirable clovers and crops particularly when using higher rates.
- Application followed by frost
Terbutryn reduces the cold tolerance of the plants. Thus avoid spraying during frosty periods. However early sown crops are more tolerant if sprayed after a period of cooler, frosty weather. See point 3
- Don’t add wetters or oils to Agtryne MA
They increase uptake and crop effect and this is why Agtryne MA can’t be applied with grass herbicides.
Before using, always read the product label. More information: |
