“The best time to tackle dock infestations in silage crops is before the first cut” says Dave Gurney, Field Technical Manager for grassland crop protection products at Corteva Agriscience™.
He adds, “It is likely that many grassland farmers already have a target date for cutting silage fields in mind and probably have a planned date written in the Farm Diary, too. What most farmers will not have put into the Farm Diary is the planned date for spraying problem weeds, such as dock, in those silage fields where a spray treatment is also planned.” It is equally important to plan this spray date, as the removal of weeds and their biomass in time for cutting silage is an important factor in maximising the quality of silage.
Any untreated docks which are cut and put into the silage clamp will impact the quality of the silage and apart from having only 60-65% of the feed value of grass, docks in silage are known to hamper a good fermentation which in turn can lead to a reduction of intake by cattle. A knock-on effect of docks being taken into the clamp is that any dock seeds present (up to 60,000 seeds per plant) can not only survive in silage, but they will pass through the cow and get into the slurry. This then leads to the infesting of fields that may not have a dock problem currently, or the re-infesting of already treated fields, when the slurry is spread.
Just a 10% dock infestation can reduce silage yield by 10% and many fields have significantly more.
Ideally, docks need to be sprayed 21-28 days prior to cutting when they are actively growing, a good dinner-plate size and prior to any seed heads emerging. This interval will help to ensure that dock leaves have decayed, so won’t be present in the silage. It also allows time for the recolonization of grass in the bare patches where docks were present, thus increasing the amount of harvestable grass.
The very wet conditions of the current winter will also lead to an increase in weed problems, resulting from poaching and other bare patches where grass has been lying under water for some time. Prompt action will be required to minimise any potential loss in productivity and the on-set of longer-term problems as weeds will fill this bare ground very quickly.
With these factors in mind, Mr Gurney suggests that farmers plan a potential spray date now by working back at least three weeks from the planned cutting date. This also means that where grass spraying is out-sourced, a contractor can be booked into their diary in good time.
Corteva offer a comprehensive range of very effective grassland herbicide solutions to cover a wide range of weed problems. Importantly, every one of these products kills down to the roots, meaning that the grassland farmer does not need to go back into the field to re-spray the same weeds again. The rapid translocation of these solutions into the roots of weeds also means that they are also the ideal choice for weed control after the first cut in multi-cut silage regimes, which are becoming more popular.
Where docks are a particular problem in silage fields consider using Doxstar® Pro. DoxstarPro controls mature and seedling docks – both broad-leaved and curled. For best effect, weeds should be sprayed when they are actively growing and at the rosette stage, 15 to 20cm across or high. The dose rate for Doxstar Pro is 2l/ha, applied in a water volume of 300l/ha (or up to 400l/ha if dock numbers are particularly high or the grass sward is dense) when standard flat fan nozzles are being used). If low drift nozzles are being used, a single water volume down to 200l/ha is supported by Corteva.
So, make sure that you have a date with a Corteva grassland herbicide in 2020 and Grow Great Grass.
Use plant protection products safely. Always read the label and product information before use. For further information including warning phrases and symbols refer to label.
*Doxstar® Pro contains fluroxypyr and triclopyr.