Cover Crops Do's and Don't's

Updated in 2026, this version replaces the 2016 Cover Crops Do's & Don't's publication.

Uncovering cover crop facts and myths about weed, insect, and disease management.

Weed Management

DO terminate cover crops using an appropriate method and timing

When and how to terminate the cover crop should fit the scenario for the given cover crop species, cash crop, and the goals of planting a cover crop. Inadequate termination of the cover crop can pose a risk of interference and yield loss with the cash crop.

DO choose the right cover crop

Choose a cover crop that will suit your needs and avoid cover crops that may be difficult to terminate or seed sources that are contaminated with weed seeds. Annual ryegrass is not recommended due to national concerns of resistance to multiple herbicides.

DON'T reduce herbicide use

Always use preemergence residual herbicides with multiple sites of action. Apply at full labeled rates to maximize weed control. Also, be aware that residual herbicides can interfere with cover crop establishment and may have additional restrictions, such as grazing or feeding harvested forage.

DON'T rely on cover crops for universal weed suppression

A well-established cereal rye cover crop with high biomass can suppress 60-80% of specific weeds, but the ability of other cover crop species to suppress weeds, particularly late-emerging species, is extremely variable.

Insect Management

DO commit to scouting

Cover crops are more attractive to insects of all types, both pests and beneficial insects, than bare, tilled soil, or fields with sparse weed cover. Scouting is the only way to know pests present in the cover crop.

DON'T treat unnecessarily

Cover crops attract many beneficial insects. Don't harm those beneficials with an unnecessary/default insecticide application.

DON'T plant immediately after terminating the cover crop if potential pests are present

Displaced insects will be hungry. Even insects that don’t normally feed on corn, soybean, or other crops will attempt to do so.

Disease Management

DON'T rely solely on cover crops to reduce diseases

Cover crops can be hosts for both beneficial organisms and pathogens, including nematodes. Cover crops can also affect the soil microenvironment, specifically temperature and moisture, and this may favor specific pathogens and disease development.

DON'T plant immediately after terminating the cover crop

Some cover crops may be a “green bridge” that can increase pathogen populations in certain cash crops. For example, cereal rye is a green bridge for seedling pathogens of corn, and a potential carrier of mite-vectored viruses that impact small grains. After terminating the cover crop, it is best to wait 10-14 days before planting a cash crop to allow pathogens and insect vector populations to decrease and reduce disease risk.

If “planting green” (planting the cash crop within a week of terminating cereal rye) is intended, planting corn into a cereal rye-free zone may reduce the risk of seedling disease and yield decline. This can be achieved by not seeding cereal rye over the future corn row, e.g., plugging a drill, or strip-tilling.

DO use multiple management practices

Disease management in cash crops planted after cover crops requires an integrated approach using resistant varieties/hybrids, crop rotation, residue management, and fungicides where needed.

Acknowledgements

Authors

Travis Legleiter, University of Kentucky; Tommy Butts, Purdue Unviersity; Kim Cassida, Michigan State University; Martin Chilvers, Michigan State University; Shawn Conely, University of Wisconsin; Alyssa Essman, Ohio State University; Wes Everman, Iowa State University; Andrew Friskop, North Dakota State University; Stevan Knezevic, University of Nebraska; Christian Krupke, Purdue University; Dylan Mangel, University of Nebraska; Alison Robertson, Iowa State University; Damon Smith, University of Wisconsin-Madison; Albert Tenuta, OMAFA; Kiersten Wise, University of Kentucky

Reviewers

Travis Faske, University of Arkansas and Daren Mueller, Iowa State University

How to cite: Legleiter, T., Butts, T., Cassida, K., Chivlers, M., Conley, S., Essman, A., Everman, W., Friskop, A., Knezevic, S., Krupke, C., Mangel, D., Robertson, A., Smith, D., Tenuta, A., Wise, K., 2026. Cover Crops Do's and Don't's. Crop Protection Network. CPN-4002. doi.org/10.31274/cpn-20190620-033.

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