Who Knew? Cover Crops, Corn and Water Molds Webinar Recap

Cover crops have numerous benefits, but not everyone is using them. Decreased yield is a major barrier but terminating at the right time can minimize risk. What are the factors that may impact yield and why does timing matter?

Dr. Alison Robertson, professor of plant pathology and microbiology and extension field crops pathologist at Iowa State University, wondered if corn seedling disease could be the culprit.

“As a pathologist, when I look at reduced stands, more barren plants, and slower emergence, I automatically think of seedling disease.”

In this month’s podcast, Robertson details the research her team is doing to determine what management practices could reduce yield drag.

They first had to determine if winter rye can even host pathogens that infect corn seedlings. They discovered that rye can host Fusarium graminearum and Pythium sylvaticum.

Next, they set up a field trial experiment seeding winter rye ahead of planting corn. They terminated five plots at different times, anywhere from 25 days before planting to two days after planting.


Cover crop test fields in Boone, Iowa.

They found that when conditions are favorable, winter rye acts as a ‘green bridge’ for Pythium to infect the corn. Fusarium was present whether cover crops were used or not and Rhizoctonia did not appear at all.

Watch Dr. Robertson’s webinar here to learn the optimal time for termination and what additional factors may change it.

Brianne Osborn