Control docks to get best from silage

Dry spring sees docks thrive

Dock populations are thriving this summer following the driest spring in over a century – and reducing silage palatability unless controlled.

Deep rooting ability allows docks to reach moisture – outcompeting grass in a way which can significantly reduce silage quality and nutrient value, says Dave Gurney, field technical manager for Corteva Agriscience.

“Effective dock management strategy is essential to maintain the productivity, palatability, and feed value of silage crops and of course to stop an existing presence getting worse each year.”

A 10% infestation of docks will lead to a 10% reduction in grass dry matter yield, says Mr Gurney – a direct correlation which will affect productivity and the bottom line in terms of enterprise profitability.

How to assess

A simple way to assess dock population is to count the number of docks in an area of 5m x 7m. If there are 10 plants, then the population is 10%, and so on. It’s a good idea to check five positions across a field in a W-shape and take the average result.

Spraying a selective herbicide with good translocation properties to ensure effective root kill is a recommended course of action, but it is important to understand the best practice guidelines which will help achieve optimal effects.

“The timing of herbicide application is crucial,” says Mr Gurney.

“You want to see active growth and have docks which are ideally dinner plate size or less. If docks are hammered by dock beetle, ravaged by ramularia discase or have started to produce a flowering stem then control is less than what it should be.”

Little foliage

Drier weather so far has caused docks to produce very little foliage and even the smallest of plants are going into the seed production growth stage, which will greatly reduce the amount of chemical translocated into the plant roots.

“A spray between silage cuts is an ideal application time. Following rain across most of the country, docks are re-emerging after cutting.”

With a typical cutting interval of around five weeks, a fast-acting herbicide is needed. It takes around three weeks for docks to grow to a suitable stage. This then leaves just two weeks for the chemical to be applied and for it to translocate to the roots of the docks.

Typically, silage fields contain straight grass, without clover, so new fast-acting selective herbicide, ProGrass will resonate. It has been launched this year and comes with a short cutting interval of just seven days, making it ideal for use between silage cuts.

Undesirable weeds

“ProGrass offers excellent translocation properties, works quickly and, apart from controlling docks, also tackles other undesirable weeds such as buttercups, dandelions and nettles.

“ProClova XL is another new selective herbicide for this year, and is clover-safe. If white or red clover are present then this is your best option. It has an impressive weed spectrum which includes docks, buttercups, dandelions, hogweed and cow parsley.”

ProClova XL is not as fast acting as ProGrass and requires a 21-day cutting interval following spraying. It favours warmer conditions where target weeds show active growth prior to seed heads being produced, says Mr Gurney.

“We have written Best Practice Guides for ProGrass and ProClova XL. These give guidance on how to achieve the best level of weed control.

“These are available via the Corteva website, and also via a new QR code on the product labels too.”