Choose the right products to control weeds in grazing pastures
Many weed-infested grazing pastures are now at or approaching the right stage for spraying.
The key to effective weed control is picking the herbicide that will give the most effective control of the target weeds present.
Timing of the spray is also very important. With systemic herbicides such as Forefront T, DoxstarPro, Thistlex, PastorTrio and Envy, best control is achieved from spraying when weeds are actively growing and before they flower.
Weed control expert Chris Maughan offers the following timing guidelines for treating some of the major weeds.
- Docks should be 15-25cm high or wide and before a seed head begins to show;
- Thistles should have four to 10 leaves and be 15-25cm high;
- Nettles should be sprayed before they flower.
“If weeds are gone beyond these stages, it is best to top them and wait for three to four weeks regrowth when they should be at the perfect stage for the most effective kill,” advised Chris, who is technical manager with Whelehan Crop Protection, distributors of the Corteva Agriscience range of systemic herbicides on the Irish market.
Forefront T the perfect grazing herbicide
When it comes to choosing the perfect broad-spectrum weed killer for grazing pastures Forefront T is the gold standard.
Manufactured by Corteva Agriscience and imbued with the most advanced chemistry in weed control technology, Forefront T has become the product of choice for a growing number of farmers seeking to clean pastures of a wide spectrum of weeds.
It contains two chemicals, aminopyralid and triclopyr. This powerful combination makes it the perfect choice for docks, thistles and nettles as well as a range of other weeds such as buttercups, chickweed and dandelions. It is also the product of choice for ragwort.
Apply Forefront T as a single application at 2L/ha in a minimum 200L water/ha. Keep stock off the pasture for seven days after spraying.
Best for ragwort
Spraying with Forefront T is the best route to effective control of the noxious weed Ragwort.
“Apply Forefront T when the ragwort is in the rosette stage and during a period of active growth with warm temperatures [above 10°].
“Animals should be kept off pasture until the ragwort has completely disappeared. This can normally take around three weeks but when the plant starts to produce a stem it could take up to eight weeks for it to die.
“In this situation, spraying in late autumn when pastures are being closed for the winter can work very well,” advised Chris Maughan.
Thistlex the best choice for thistles
Thistlex, another Corteva Agriscience product, is the perfect product for long-term control of both creeping and spear thistles.
Animals leave 30cm (12in) ungrazed around each thistle plant. An infestation of 50 thistles/20m², a common occurrence in heavily-infested pastures, will cut grass dry matter yields in half.
Thistles also pose disease risks such as orf in sheep and pink eye and mastitis in cattle.
When using Thistlex, you are assured that the chemical is translocated right down to the thistle roots. In contrast, hormone-based products have very little impact on the root system. While killing the foliage of the thistle, they merely act as a chemical topper.
Apply Thistlex at 1L/ha and keep animals off pasture for seven days after spraying.
DoxstarPro for dock-free aftergrass
Had you a problem with docks in your first-cut silage ground this year but didn’t have an opportunity to spray them before the silage was cut?
You will have suffered a reduction in the yield and quality of your silage.
But you will shortly have an opportunity to stop the rot and control this pernicious weed in aftergrass, leading to a big increase in grass output and animal performance for the rest of the year and beyond.
Docks should be at the ideal stage for effective treatment with DoxstarPro three to four weeks after silage is cut.
It should be applied at a rate of 2L/ha as a single application or two applications of 1L/ha six to 12 months apart.
Envy or PastorTrio ideal for reseeds
Weed control is now becoming an urgent priority on many pastures reseeded in recent weeks.
Reseeding has major advantages in replenishing pastures and lifting overall farm productivity. But if weeds are not controlled early, much of the investment can be wasted.
“Envy, one of the newest herbicides from Corteva Agriscience, is tailor-made for reseeded pastures,” said Chris Maughan.
Containing two powerful active ingredients fluroxypyr and florasulam, it is effective on a wide range of weeds including chickweed, docks, dandelions, buttercups, plantains, mayweed, charlock, fumitory and dead nettle.
PastorTrio, another recent addition to the Corteva AgriScience range, is another highly effective option for controlling weeds in new reseeds.
As well as containing florasulam and fluroxypyr, the two ingredients found in Envy, it also contains the potent ingredient clopyralid.
It is effective on the same range of weeds as Envy and is also powerful on thistles, which can be a serious problem in new reseeds.
The recommended application rate for PastorTrio in new reseeds is 1L/ha in 200L of water, from the third leaf visible stage of the grass. Envy can be used at 1.5L/ha and is ideal where chickweed or docks are large.
Envy and PastorTrio are also effective in controlling weeds in grazing pastures and silage/hay swards. The recommended application is 2L/ha in 200-300L of water.
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