Thanks for signing up!

Look for the Digest in your email twice a month.

Follow Us

Sign up for our Digest to receive the latest agronomic insights and crop management advice for your primary growing region delivered twice a month to your inbox.

Plan for the Battle Against Rhizoctonia in Potatoes

February 17, 2019
This agronomic image shows Elatus fungicide vs. inoculated potatoes

Elatus® fungicide 0.5 oz/1000 row feet vs. Inoculated check

You may not be able to see what is lurking underneath your fields, but you can plan now how to protect against it. Rhizoctonia is a common soil inhabitant in the Pacific Northwest that overwinters underground, waiting to infect potato crops. Once the plant is infected, Rhizoctonia can cause all sorts of issues: slowed emergence, reduced stand and/or weakened plants. Ultimately, the damage is felt in fewer marketable potatoes.

Black scurf is the most noticeable sign of infection, and causes black patches along the tuber. These lesions form on potatoes at or below the soil line and impede vascular function in roots. As Rhizoctonia progresses, it can stunt growth and cause the formation of aerial tubers, and can attack and kill germinating sprouts. Understanding correct management techniques is crucial for protection. Following these essential tips will help alleviate disease pressure:

  • Avoid over-irrigating: Cool, damp soil can cause slow plant emergence and encourage fungal development.
  • Plant strategically: Encourage more rapid emergence through shallow planting.
  • Use in-furrow fungicide: Select a product with multiple modes of action and excellent preventive activity.
  • Harvest timely: Potatoes should be harvested as soon as skin is set. The percent of infected tubers increases as the interval between vine kill and harvest increases.

Long-term Impact of Rhizoctonia

Healthy soil is essential to growing healthy potatoes, but when soilborne diseases like Rhizoctonia are present, crop production can be hampered. Black scurf reduces tuber quality, and Rhizoctonia can cause losses nearing 30% of marketable yield.

Syngenta recommends Elatus fungicide to control Rhizoctonia and other key soilborne potato diseases. With 2 active ingredients, Solatenol® fungicide and azoxystrobin, Elatus adds a preventive component to help stop Rhizoctonia before it becomes a problem, ultimately resulting in improved potato emergence, more uniform crop stand and enhanced crop health. Now with the recent MRL approval in Taiwan, you have the opportunity to export your crop to more markets.

Sign up for the Know More, Grow More Digest to receive twice-monthly agronomic e-mail updates pertinent to your area.

All photos are either the property of Syngenta or are used with permission.

Syngenta hereby disclaims liability for third-party websites.

The potential gap between U.S. approvals and foreign import tolerances or MRLs is a global trade issue that affects all pesticides. Syngenta’s approach with MRLs is all about transparency and engaging proactively with our channel customers, growers and exporters to present current MRL information. Syngenta is engaged in ongoing international efforts to harmonize MRL standards. As MRLs may change from time to time, please check with the Environmental Protection Agency (EPA) and U.S. Department of Agriculture Foreign Ag Service (USDA FAS) Global MRL Database (https://www.globalmrl.com/db#login) for a complete list.