Pest of the Month: Rhizoctonia

{Sponsored} As far as pest and pestilence go, rhizoctonia is one of the few that appears in every potato growing region on a consistent basis. Besides the obvious problems with yield and black scurf that growers have when rhizoctonia is out of control, the other issue is the lack of diversity in chemistries used to fight rhizoctonia.

Strobilurins are the most widely used chemistry, but growers can run into yield loss as well as resistance management issues when strobilurins are used alone to fight rhizoctonia.

Scott Ockey, field development manager for the Western U.S. at Certis USA LLC, recommends growers combine the use of strobilurins and other products with some other methods of control, such as cultural practices and a biological to both combat the fungus and the yield loss.

scott_Ockey_certis usa
Scott Ockey

Ockey recommends these practices in order to reduce the number or severity of outbreaks of rhizoctonia:

1. Cultural practices: Increase the speed to sprouting, such as by using the deep planting with shallow soil cover methodology in order to promote a faster emergence.

2. Crop rotation: Growers need to rotate potatoes with other crops besides sugar beets or alfalfa, which are both susceptible hosts for rhizoctonia in soil.

3. Clean seed: Be certain growers start with clean seed. University seed certification programs will provide the details about the levels of inoculum, bacteria, fungi and virus in seed lots to the seed producers, who will provide that information to growers. Only work with clean seed to reduce the chances of major rhizoctonia and other disease infections.

However, once rhizoctonia has invaded a field, using the right treatments is key to controlling it and reducing the negative effects it can have on a field. Combining traditional chemistries like strobilurins with newer technologies such as the biofungicide Double Nickel®, from Certis, creates the strongest duo in the battle against rhizoctonia infections.

By adding Double Nickel, growers can improve the yield they could otherwise lose to rhizoctonia or strobilurins. “Compared to strobilurins, Double Nickel can average 10-15% increased yield over potatoes only treated with strobilurins,” Ockey said. Fields with lower levels of inoculum may not have results that dramatic, but it’s a possibility, according to Ockey. In other words, it negates that yield reduction often seen with strobilurins.

Plus, Double Nickel isn’t just used for rhizoctonia. “While it does control rhizoctonia, and is reliable in combination or as an alternative to strobilurin fungicides, it also has efficacy on a number of potato diseases, such as early blight and white mold,” said Jeremy Adamson, product manager at Certis USA.

For more information about Double Nickel, visit

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 © 2021 Certis USA LLC

75 Applewood Dr. Ste. A
P.O. Box 128
Sparta, MI 49345


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