15 March 2002

Dock control duo get approvalfor new leys

TWO herbicides already available for controlling docks and chickweed in established swards can also be used for infestations in new leys, according to Dow Agroscience.

Both Doxstar and the annual weed herbicide Pastor are now registered for use on new leys, says its marketing specialist Donald Westwater.

"Weed control during establishment is crucial, as seedlings are unable to compete." Mr Westwater believes chickweed is the most aggressive annual weed in new leys and ryegrass numbers will already be reduced to about half the target sward population when 10 plants/m sq are found.

With docks, a long-term control programme can increase silage quality and boost grass yields without having to plough up swards, as found on one Leics unit.

Swards were heavily infested with dock populations approaching 30%, says Roger Cook, who farms near Whitwick, Leics. "This was reducing grassland productivity and dock silage is not an ideal forage for the 90-cow dairy herd.

"But soils are thin, with frequent outcrops of rock which meant ploughing and reseeding was not a practical option. Instead, a five-year spraying programme was implemented using Doxstar, applied at 3.7litres/ha in spring and autumn."

Split applications make the programme flexible. When spraying doesnt fit in with other spring grassland operations, they can be left and treated in autumn, explains Mr Cook.

"Docks are now under control with only fields or patches where dock seeds germinate being treated. It has only taken three years to achieve virtually dock-free swards; well within the expected five years."

Mr Cook has not gone down the high clover route, having permanent ryegrass swards, which are ideal for this product. &#42