2018 Weed Management Starts during Harvest 2017

Daniel H. Smith- Nutrient and Pest Management Program, University of Wisconsin-Madison






As we approach fall and harvest fields that may have weed escapes, we should have a plan to limit the spread of weed seeds. Weeds seeds can easily be spread through harvest and tillage equipment. Taking the time to clean equipment before moving to the next field or bringing to the farm for the first time can be a worthwhile investment with many advantages. For example, a single common waterhemp can produce 250,000+ very small seeds that can easily be stored on equipment and redistributed in fall field operations. Regardless of the weed species, avoiding the spread of the weed seed is necessary to prevent future costly weed management problems. Avoiding very heavy weed infestations and consider harvesting or tilling these areas last, especially when herbicide resistant weed species are present.

Combine Cleaning

The combine operation manual should be reviewed prior to any cleaning produce. Always read, follow, and understand the manual and related safety instructions. Cleaning a combine will produce a lot of dust and debris and personal protective equipment should be used. A clean combine may also reduce the risk of a fire occurring during a busy harvest season.

Combine cleaning can be very time consuming, and a through cleaning should be done prior to storage or when combining a field of identity preserved grain. A quick field cleaning operation can be done with a leaf blower or an air compressor. Cleaning the head, feederhouse, rock trip, threshing and separating unit, sump on the unloading augur, and grain tank will help reduce the chance of spreading weed seeds. Removing any residual debris on the outside of the combine, engine bay, and residue management system is also necessary. Investing 30 minutes in combine cleaning after harvesting a weedy field will reduce the chance of spreading problematic weed populations to other fields.

Tillage Equipment

Soil on tillage equipment may also contain weed seeds and should be removed before transport. Although time consuming, removing as much soil as possible from tillage equipment and equipment tires will lessen the chances of transporting weed seeds from field to field. Avoid weed seed movement to help control future costs of weed control and herbicide resistance management.

More information on herbicide resistance management:


More information on combine and tractor fires:


More information on where grain hides in a combine:


More information on combine clean-out procedures: