Soybean growers in the Midwest face a new challenge with red crown rot, a yield-threatening disease that is on the rise. With no effective in-season treatments currently available, growers are facing increasing difficulties in managing this emerging issue.
RCR, caused by the fungus Calonectria ilicicola, infects soybean seedlings within the first three weeks after germination. The disease spreads primarily through infected soil and crop residue, leading to yield losses ranging from 10% to 80% in severely affected fields, depending on environmental conditions.
Originally confirmed in U.S. peanut production in the 1960s, RCR was first detected in soybean crops in the southern U.S. during the 1970s. The disease has now been identified in 11 soybean-producing states, including Illinois, Indiana, Iowa, Kentucky, Missouri and Ohio.
To help growers address this issue, CeraMax, a biological seed treatment developed by Ceradis Crop Protection B.V., will be available in 2025 under a Section 2(ee) label for the suppression of Red Crown Rot in soybeans.
States where CeraMax Section 2(ee) labeling applies are Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, Tennessee, West Virginia, and Wisconsin.
How CeraMax works
CeraMax contains the active ingredient Natamycin, a biological molecule produced by soil bacteria that prevents soil-borne fungal diseases from attacking plant roots.
By stimulating the defensive capabilities of the treated seed at planting and germination, CeraMax activates key defensive pathways before fungal infection occurs. This early activation allows the seed and plant to utilize its genetic resistance by “priming” plant physiology, enabling it to defend against disease before it takes hold.
Recognizing the signs of red crown rot
One of the biggest challenges in managing red crown rot is its frequent misdiagnosis as sudden death syndrome.
Bob Joehl, seed protection specialist or Direct Enterprises Inc., stresses the importance of recognizing the signs and symptoms of RCR.
While both diseases infect seedlings at planting and have similar leaf foliage expressions, Joehl recommends inspecting the stems of plants closely for accurate identification of specific disease characteristics.
Risk prevention strategies
Since its market introduction in 2019, CeraMax has consistently provided effective protection against sudden death syndrome and, more recently, red crown rot under the Section 2(ee) label recommendation for disease suppression.
For the 2025 season, CeraMax will be available through Direct Enterprises, Inc. and the WinField United retailer network. For more information, visit ceradis.com.
