Add another to the list of pesky weeds that have invaded Canada from elsewhere. White cockle has been making itself a nuisance in several fields in the Clearwater county area. Once this noxious weed gets established in forage stands it becomes very difficult to eradicate.
White cockle was introduced from Europe and can grow as an annual, biannual or at times as a short-lived perennial. This weed prefers full sun and well-drained soils. The plant emerges early in spring, forms a taproot and then spreads large roots. The stem and root pieces can sprout to form new plants, so cultivation may spread an infestation.
White cockle has a hairy stem, grows 30 to 120 cm tall and can have several stems per plant. The flowers are numerous, fragrant and arranged in spreading clusters. Flowers are white or pinkish with five notched petals that open in the evenings.
Kim Nielsen, manager of agricultural services with Clearwater county, told the West County Ag tour in the middle of August that once the plant is established, it is very difficult to control.
“It’s a real struggle because of its ability to get into hayfields,” said Nielsen. If it gets established, there are additional concerns about contaminated hay and forage seeds.
There are no registered herbicides to assist in the fight against white cockle. Dan Cole of Alberta Agriculture’s Ellerslie research station, has found that DuPont’s Express can help burn off white cockle. However, this same product can also injure clovers and alfalfas. Trials in 2006 resulted in an alfalfa crop that turned brown, but a productive crop returned the year after with little stand reduction, said Nielsen. “By the time you take the cockle out and the grasses move in, it’s a pretty decent tradeoff,” he said.
Frequent mowing can reduce seed production. In smaller infestations, the removal of the female seed capsules can also be effective. Producers can pinch off the female capsules that are swollen with seed, as these capsules will not grow back.
More people in the county seem to be battling white cockle in their pastures as well as hayfields, said Nielsen. “Even with good grazing management, it’s not all that easy to take it out,” he said. Aggressive forage crops can also outcompete white cockle.
The county is currently experimenting to determine best practices for eradication of the weed. Nielsen said spraying the weed is worthwhile, and it is much better than leaving the weed to seed out. However, even spraying will not be a quick fix.
Strategies may involve weakening the plant and removing it in August or spraying it in the spring. Removing the weed in silage is another option.
White cockle seeds are similar in size to clover and alfalfa, so it is easy for forage seed to become contaminated. The seeds are kidney shaped and have little bumps, which makes them hard to remove from seed mixes. Once the seed is introduced into a field, reinfestations are common.
Nielsen stressed that all producers talk to people about seed and know what they are buying. “Too many people buy seed without asking for the seed-testing certificate,” he said. “I can’t stress that enough. We have pushed for years to get seed-testing certificates to be part of the label on a sack of seeds.”
He told producers never to buy forage seeds unless they know exactly what they’re buying. “The only way to know what you’re buying is to get the certificate,” he said.
“Toomanypeoplebuy seedwithoutasking fortheseed-testing certificate.”