Can harvest weed seed management be used to control kochia, cleavers and wild buckwheat?

The Challenge

Kochia, cleavers and wild buckwheat are broadleaves that have become more problematic and difficult to manage in canola.

The Project

Determine the amount of weeds seeds that remain on kochia, cleavers and wild buckwheat at harvest time and assess the efficacy of pre-harvest herbicides in reducing viable weed seed production.

The Results

Seed shed for kochia, cleavers and buckwheat can be determined by growing degree days. Cleavers and buckwheat shed 10% of their seeds earlier (1390 GDD) than kochia (1585 GDD). No evidence that pre-harvest herbicide application was beneficial in preventing weed seed set or reducing weed seed viability, rather encouraged shattering of mature weed seeds.

Grower Benefits

Harvest as early as possible to reduce weed seed shed, but with the use of chaff collection or pulverization techniques. Focus on timely harvest rather than pre-harvest to aid in weed seed management.