Grain harvest for the 2021 growing season is underway and pest management may not be the number one concern on a farmer’s mind. However, harvest is an optimal time to limit the spread of weed seeds according to Kimberly Schmidt, University of Wisconsin-Madison Division of Extension Shawano County agriculture educator.

“Because weeds that are still in the fields have survived other control attempts during the growing season, these weeds have the potential to be difficult to control if allowed to germinate,” she said.

Herbicide resistance in weed populations has increased in recent years and all facets of pest management should be considered, such as cleaning combines between fields.  

Cleaning your combine between fields can reduce the spread of weed seeds. There can be up to 150 pounds of biomaterial in a combine, most likely containing weed seed.

A case study in 2019 from Wisconsin Cropping Systems Weed Science Lab, collected biomass samples from combines. When the samples were mixed with soil and potting mix 97% of samples had viable weeds emerge. This case study also indicated that focusing on head and feeder house of the combine when cleaning would provide the greatest impact reducing weed spread. Cleaning a combine can take as little as 20-30 min and save you time and reduce pest management costs in the future.