Weed of the Week: White cockle

It might look like other night flowering weeds, such as catchfly, but this invasive pest is expanding rapidly through reduced tillage fields in Western Canada.

The pest typically shows up as white flowers amongst a yellow canola crop, where it competes for water and fertilizer resources.

It is a tough weed to control for many producers once it reaches its short-lived perennial stage.

White cockle’s Latin name is sailene latifolia and is also known as white campion.

It produces large numbers of seeds, has a tough, deep taproot and once established is challenging to remove from the field.

It grows 25 to 75 centimetres tall at maturity and has oblong, hairy leaves with smooth edges. Flowers are fragrant, white, about two cm across and open at night.

The majority of the plant’s pollination is insect based and takes place during the late evening hours.

University of Saskatchewan research indicates that a two stage approach to the weed is the most effective when it comes to controlling this pest.

Dicamba (Banvel) mixed with 2,4-D or MCPA is used in cereal crops when the weed is in the two to four leaf stage. Dicamba at a rate of .12 litres per acre and 2,4-D or MCPA in a 500 gram formulation are applied at .35 litres.

Saskatchewan Agriculture recommends a spring burnoff of glyphosate applied at standard rates, as well as the addition of a Group 2 product such as 2,4-D where appropriate.

Group 2 and 4 products are useful in controlling the pest in crop. Roundup Ready crops also provide effective control when the glyphosate is applied as a post emergent product and the timing is right to control late emerging weeds.

A pre-seed burnoff will control seedlings by itself, but often not perennials.

Ken Sapsford of the U of S said an application of herbicide in a cereal crop after glyphosate or a mix of glyphosate and florasulam (Prepass), tribenuron and metsulfuron (Express Pro) or 2,4-D can be effective.

Group 2 combination products such as Precision Pac 23235, containing thifensulfuron, tribenuron and metsulfuron, and Precision Pac 2525, containing tribenuron with 2,4-D and dicamba or with the addition of MCPA, can be useful in controlling white cockle in spring wheat, durum and barley.

Tribenuron and metsulfuron should not be applied if the burn-down application contains those chemicals because it would exceed annual rates of application.

In alfalfa and clover, white cockle is treated with 2,4-DB products such as Cobutox, Embutox or Caliber in the 625 grams per litre formulation.

White cockle causes seed purity issues in timothy, alfalfa and clover because seed growers find the seeds impossible to clean from the crop.

In established pasture, a mix of dicamba, 2,4-D and mecoprop-p (DyVel DSp) can be applied at a rate of 1.3 litres per acre.

There is a 30 day grazing restriction on these products.

Cultivation provides effective control, but it isn’t recommended for most rotations or where carbon credits have been claimed.

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