Fusarium Root and Stem Rot

Fusarium root and stem rot is believed to be of minor importance and causes limited economic loss in the U.S. Plains states. However, the disease is becoming an emerging problem in a few sunflower producing countries such as Russia and China.

Fusarium root and stem rot is caused by multiple species of Fusarium in sunflower, which are soil- or residue-borne and can infect plants through the roots. Conditions favoring disease development are dry weather early in the season, followed by wet weather conditions during mid-season and warm/hot temperatures (80 to 100 F). Infection results in pinkish to reddish-brown colored symptoms on or inside the roots or shoot of the plants. Additionally, premature senescence and browning of the outside of the stem can be observed on plants that are severely infected. Because of the infection, the vascular system can be constricted and the water transport capacity of the plants can be limited.

Fusarium stem rot is also associated with charcoal rot, which complicates the economic importance of this disease. Strategies specific to management of Fusarium root and stem rot is not justified for use in sunflower production. However, potential economic losses associated with the disease may be alleviated by reducing plant stress.

fusarium in stalk — Figure 2. Fusarium infection resulting in pink colored vascular tissue.

Images

Figure 1. Premature senescence and browning of sunflower caused by Fusarium root and stem rot (Bob Harveson, UNL)
Figure 2. Fusarium infection resulting in pink colored vascular tissue (Sam Markell, NDSU)

Additional Resources

Fusarium sp. associated with stem diseases on sunflowers (Mathew et al.)

Identity and pathogenicity of Fusarium spp. isolated from sunflower (Mathew et al.)

Other NSA Resources

Photo Gallery
The Sunflower Magazine's Archive section
Approved Chemicals

Disclaimer statements

Information based in part on and reproduced from Kandel, H., Endres, G. and Buetow, R. 2020. Sunflower Production Guide. North Dakota Extension Publication A1995. Informational updates made possible by the Sunflower Pathology Working Group, and is/was supported by the USDA National Institute of Food and Agriculture, Crop Protection and Pest Management Program through the North Central IPM Center (2018-70006-28883).