Check Double Crop Soybeans for Diseases

Rhizoctonia solani and southern root knot nematode have been confirmed in southeastern Illinois.

Published on: Aug 11, 2011

While scouting research plots in southeastern Illinois the week of July 27, Southern Illinois University Carbondale professor of plant pathology and Illinois Soybean Association researcher Jason Bond, Ph.D., encountered significantly elevated infestations of two potentially devastating pathogens in double crop soybean fields: Rhizoctonia solani and southern root knot nematode.

In the wake of this discovery, Bond and ISA are urging all Illinois soybean farmers to scout their fields for these and other diseases that can negatively impact yield.

"Basically, I walked into areas of the double crop fields that seemed to be struggling and found the problems," explains Bond. "The intense heat we've experienced over the past few weeks has exacerbated the damage caused by Rhizoctonia solani and southern root knot nematode in late planted soybeans. Now is the optimal time for producers to scout recently planted fields to diagnose stand issues, especially if the field recently received rain. The problem areas will stand out for another week or two."

He adds that "The southern root knot nematode pathogen will be most severe in sandier areas of a field. Plants affected by this pathogen will often exhibit severe galling on the roots. Rhizoctonia solani is a fungus and is not as limited by soil type. Damage caused by this pathogen happens soon after the plant emerges, and the heat is just adding to problem of the compromised roots and stems. Soybean plants infected by this pathogen often have brick red lesions on the stems along with swollen hypocotyls. Sometimes, the seedlings have slightly twisted stems."

Soybean farmers who find suspicious seedlings can get a free plant diagnosis through an ongoing SIUC research project that is being funded by ISA's and the United Soybean Board's checkoff programs. They simply need to collect suspicious plant or soil samples in a plastic zip-lock bag and submit them to SIUC at: Plant and Soil Science, 1205 Lincoln Dr., Ag. Bldg., Rm. 176, Carbondale, IL 62901. Questions about the program may be directed to the research team by calling (618) 453-4309 or emailing jbond@siu.edu.

"It's times like this when ISA's research partnerships really pay off," states Dean Campbell, ISA District 17 director. "Jason spotted a problem and notified our office immediately, so we could get the information out to farmers as quickly as possible… before they suffer production and yield losses. This is a perfect example of how checkoff-funded research directly benefits the industry!"

For those individuals who are interested in viewing samples of Bond's findings, the ISA website – www.ilsoy.org – features a new photo gallery comprised of the pictures he took while in the field. Bond also encourages farmers to visit www.soybeandiseases.info to review the results of another ongoing Illinois soybean checkoff-funded study that is evaluating root knot nematode resistance in commercial varieties.