Some plant pathologists maintain green bridge is not likely to be a disease concern with the traditional Midwestern corn-and-soybean rotation. But with the expanding growth of cover crops and adoption of other crop rotations, it’s a possible disease worry for Corn Belt no-tillers.

Green bridge is the term applied to volunteer plants, weeds and maybe some cover crops in green-up situations, where the pathogen inoculums and pest populations increase between the harvest of one crop and the emergence of a newly planted crop.

When it comes to effective no-till management, it often boils down to making the correct diagnosis between root disease and allelopathy problems In fact, some Pacific Northwest no-tillers say managing green bridge takes a new way of thinking — similar to learning to deal with an infectious disease after years of being treated by your doctor for an allergy.

40-Year Concern

Just ask Allan Brooks, who is now convinced he’s seen green bridge in his cover-crop program for more than 40 years. After seeing the problem years ago when seeding cereal rye as a cover crop, it’s only in the past few years that the Markesan, Wis., no-tiller has figured out that it’s a green-bridge problem.

A major worry for years among no-tillers in the Palouse area of southeastern Washington, northeastern Oregon and southwestern Idaho, green bridge is a big concern with continuous winter- and spring-wheat production.

“Green bridge is a concern for us when we use winter wheat as a cover crop and don’t get a…