As the combines roll and this year’s crop comes out of the fields, producers should scout for weed escapes and weed population shifts on their corn and soybean acres. It is a good opportunity to note any pest problems that needs to be corrected for next year’s production.
Be sure to note where the exact locations and details of weed patches or poor producing spots. Producers can compare in-field yield notes to yield monitor data to help determine the reason why a certain area of the field may not as been as good as rest of the field. This will provide information to plan any possible control measure for these problems over the winter.
Be on the lookout for weeds that may have slipped through the early season herbicide program. These weeds likely emerged after a post-emergence treatment of after a pre-emergence treatment has become ineffective. They probably developed in areas where the crop is thin or it didn’t canopy rapidly. Large weeds that are found in the crop are present due to the primary weed control program not controlling them. Evaluate this problem with a critical eye to determine if there is a real problem or not. They may not affect yield this year but they will serve as a seed bank for next year’s weed crop.
If you are seeing consistent but limited weed populations present in the field or in fields, it may be necessary to determine if the weeds are becoming herbicide resistant. There may be other reasons why this is happening. However if there are dead weeds present next to large healthy ones or scattered large plants or small patches of weeds not controlled with the present herbicide program, mark and monitor the site for next year.
Suspect weeds can be checked through Extension Weed Management at South Dakota State University. Contact the Department of Plant Science at Brookings for details. The SDSU Extension Weeds program can be reached at (605) 688-4591 or visit the department on-line.
Watch for weed patches across the field when combining. These patches can be a sign that the herbicide program was not uniform. They will be next year’s seed and if proper weed management adjustment isn’t made to control them they will persist or may become larger.
It is also important to watch for perennial problems that need special attention. There is recommended to watch along fence lines and areas adjoining the field to help control any problem weed species, particularly noxious weeds that need treatment.
Today’s precision agriculture equipment makes tracking weed problems much easier. However remember that the information obtained is only as good as the information gathered. Now is a good time to record this year’s weed information and concerns for critical analysis later.