Know Your Enemy – Wild Buckwheat Biology
By Kaeley Kindrachuk, TechAg, Crops Extension Specialist, Outlook
Producers who deal with wild buckwheat every year know it is a problematic weed for the farm. Wild buckwheat is prevalent around the province; it has been ranked third in weed surveys since the 1970s. Like other weeds, it is helpful to know more about them so that management is easier.
Wild buckwheat is an annual, tap-rooted weed that spreads horizontally until it vines up plants. It can be distinguished by its arrow-shaped leaves that are pointed at the tips. It causes lodging in crops, gets tangled in equipment at harvest and can contribute to high levels of dockage in harvest samples.
Wild buckwheat can germinate throughout the year, though most will germinate in early spring and by mid-June. If the weed germinates earlier in the spring and doesn’t have to compete with other weeds or crops, one plant could produce up to 30,000 achenes, but if germinated later in the spring, could produce up to 15,000. Achenes are a type of simple dry fruit, which many plants produce, that contain the seed. Strawberries and sunflowers also produce achenes. Achenes are usually dormant when first harvested due to the hard pericarp, which acts as a barrier to germination. Under regular field conditions, most viable achenes will germinate within the first year, but some germination can occur in following years.
Control wild buckwheat early so the weed does not compete with the crop for water and nutrients. Control can start before weeds are emerged, as there are many herbicide options to use from pre-emergent to in-crop products. The weed control tables in the Guide to Crop Protection outline which products to use in certain crops. Another key to managing wild buckwheat is to scout to know if it is present, what other weeds are present and the abundance of each. In 2007, wild buckwheat samples in Alberta were found to be resistant to group 2 herbicides, but none have been found since. While herbicide resistance is not a problem now, ensure you rotate your herbicides and use multiple modes of action in your weed control regime to keep it that way. Wild buckwheat density has been found to decrease under zero-till operations.
When you manage issues in a crop, keep in mind that knowing more about what weeds you are dealing with helps to get the weed under control. Wild buckwheat can be a problem in crops, but by managing it early in the growing season and using the correct herbicides, it should cause fewer issues. For more information contact the Crop Protection Laboratory about Herbicide Resistance Testing; or contact your local crops extension specialist.
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