Teagasc research has shown that a 10% infestation can cut silage dry matter yield by 10%. A severe infestation can reduce dry matter by up to 50%. Silage quality is also reduced through poorer fermentation. And dock stems can do serious damage to the quality of baled silage through puncturing of the film.
Quality silage is the cheapest winter feed. But fertilising and ensiling docks leads to poorer yield, lower quality and increased cost per tonne of dry matter, thereby eroding the economic advantages of quality silage.
DoxstarPro the specialist herbicide
Where dock-infested first-cut silage swards are three weeks or more away from cutting, it will pay handsomely to spray them now with the specialist docks herbicide DoxstarPro.
Manufactured by Corteva Agriscience and containing two powerful chemicals, triclopyr and fluroxypyr, DoxstarPro ensures the most effective kill of the dock root system. It is also effective on chickweed and dandelions. And unlike dicamba-based products, it has the advantage of not causing any check to grass growth.
The ideal time to spray
Weed control specialist Chris Maughan, manager with Whelehan Crop Protection stressed that timing of the spray is the key to effective control of docks with DoxstarPro.
“The ideal time to spray silage swards is two to four weeks after nitrogen is applied when docks are at the perfect stage for an effective kill.
“The docks should then be actively growing and be 15-25cm high or across and before a seed head begins to appear.
“Wait a minimum of three weeks after DoxstarPro is applied before cutting the silage. This ensures that the chemicals get fully translocated down to the root system, a vital factor in achieving long-term control,” said Chris.
Where docks are gone beyond the ideal stage for spraying and where crops are three weeks or less away from harvesting, the advice from Chris is to harvest the crop and forfeit the yield and quality advantages.
“Allow the aftergrass to grow for three to four weeks and then spray with DoxstarPro when the docks should have reached the ideal stage for an effective kill.”
Contains two powerful chemicals, triclopyr and fluroxypyr.Apply at a rate of two litres/ha as a single application or two applications of one litre/ha six to 12 months apart.Best results are achieved when docks are actively growing, are 15-25cm high or across and before a seed head appears.Leave at least three weeks between spraying and silage harvesting.Use a minimum of 300 litres water/ha (30gals/acre).When using low drift nozzles, eg guardian air nozzles, water volume can be reduced to 200 litres/ha.
Docks are a pernicious weed. The roots can be up to a metre deep and a single mature dock produces up to 80,000 seeds. The seeds remain dormant in the soil for years.
PastorTrio gives wide spectrum of control
PastorTrio, another Corteva Agriscience product, should be the herbicide of choice in silage swards where a range of weeds such as docks, chickweed and thistles are present.
Containing three active ingredients – florasulam, fluroxypyr and clopyralid it provides a very wide spectrum of weed control.
As well as docks, chickweed and thistles, it is also powerful on other weeds, including dandelions, buttercups, daisies and plantain.
As with DoxstarPro, timing of the spray is crucial. It should be applied two to four weeks after nitrogen is applied and at least three weeks before the silage is cut, for the chemicals to be fully translocated to the root system of the weeds.
Envy is another option
Envy is another effective option for weed-infested silage swards. Containing the two active ingredients fluroxypyr and florasulam, it is powerful on the same range of weeds as PastorTrio, with the exception of thistles.
Forefront T the all-purpose grazing herbicide
Forefront T is effective on ragwort. Keep stock off the treated area until the ragwort has fully died and disappeared.
When it comes to broad spectrum weed control in grazing pastures, there is nothing to beat the Corteva Agriscience herbicide Forefront T.
Containing the two powerful ingredients, aminopyralid and triclopyr, it is effective on docks, thistles, nettles and a range of other weeds such as buttercups, chickweed and dandelions, making it the ideal all-purpose weed killer. It is also highly effective on ragwort.
Apply Forefront T as a single application at two litres/ha in a minimum 200 litres water/ha. Keep stock off the pasture for seven days after spraying. Forefront T does not result in any check to grass growth.
Best results are achieved when weeds are actively growing and are at the right stage for a good kill.
If ragwort is among the target weeds, stock should be kept off the treated area until the plant has fully died and disappeared.
The perfect all-purpose weed killer in grazing pastures.Contains two powerful ingredients - aminopyralid and triclopyr.Effective on a wide range of weeds, including docks, thistles, nettles, buttercups, chickweed, dandelions and ragwort. Allow seven days grazing interval following spraying.Where ragwort is present, keep animals off the sprayed area until all plants have disappeared.
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