Options for Early Dock Control

Options for Early Dock Control

Tuesday, March 9, 2010

Tackling docks can begin from late March in many grass leys destined for silage and will protect silage yields and quality, says Duncan Connabeer, technical support manager for H L Hutchinson.

"Docks are bad news in grassland as they compete for light, nutrients and moisture," explains Duncan. "Trials have shown that a 10% infestation of docks will cause 10% loss of grass; equivalent to one trailer load of silage in 10.

Docks are a formidable foe, with an estimated 15% of productive grassland infested and a potential seed bank of 12.5million seeds/ha in the top 15cm of soil, he adds. Fields used for silage are most at risk due to the open nature of the sward, which allows established docks to spread and viable seeds to germinate.

"In the south, treatment could start as early as the end of March - as long as docks have reached the rosette stage, are actively growing, and look green and healthy. Reddy blue leaves indicate that plants have been frosted, and herbicide uptake will be poor.

"Docks respond well to nitrogen, so a good time to spray is two to four weeks after the first fertiliser application, as they should be actively growing by then.

"If it is not possible to treat pre-first cut, leave the aftermath for two to three weeks to allow sufficient re-growth before spraying. This will give good control, as weeds will be at a uniform stage of development," says Mr Connabeer.

When treating weeds early it is important to select a herbicide that will not damage the grass.

"Translocated herbicides, such as Doxstar, can control target weeds without checking the important first flush of spring grass," says Robin Bentley grassland herbicides product manager for Dow AgroSciences. "So docks can be tackled early without concern.

"Modern translocated herbicides do a good job on weeds without adversely affecting grass. The way they work also gives longer lasting control, so users can still benefit two to three years after treatment," he adds.

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