08/19/21 Sugarbeet Report

Even with dry conditions sugar beet diseases can be a major problem. Mohamed Khan, NDSU and University of Minnesota Extension sugar beet specialist, joins the Sugar Beet Report to talk about the most common diseases this growing season

Speaker 1: Bruce Sundeen, NDSU Agriculture Communication and Host
Speaker 2: Mohamed Khan, Extension Sugarbeet Specialist at NDSU and the University of Minnesota,

Bruce: 
Sugarbeet diseases have certainly not gone away and unfortunately, thre is a new one on the horizon. Mohamed Khan, Extension Sugarbeet Specialist at NDSU and the University of Minnesota, is here to give an update. 

Mohamed, what are some of the diseases that affected sugarbeets this year? 

Mohamed: 
Some of the common diseases that affected sugarbeet crop include Rhizoctonia root rot, Aphanomyces root rot, Fusarium yellows,  Cercospora leaf spot and a possible new disease caused by Sclerotinia.

Bruce: 
What causes Rhizoctonia and how can you manage this disease?

Mohamed: 
The fungus, Rhizoctonia solani, causes Rhizoctonia damping-off and root rot of sugarbeet. All commercial seeds now have a fungicidal seed treatment that typically will provide early season protection from damping-off. The use of a Post application at the 4 to 6 leaf stage with a fungicide such as azoxystrobin provides protection from Rhizoctonia root rot. Growers are encouraged to continue their use of crop rotation with a non-host such as wheat and barley to reduce inoculum pressure.  Most importantly, growers should use improved Rhizoctonia resistant varieties in fields with a history of the disease. ca  

Bruce: 
What can you tell us about Aphanomyces?

Mohamed: 
Aphanomyces damping-off and root rot are caused by Aphanomyces cochlioides. This pathogen must get free water in the soil to cause infection. Dry conditions throughout the growing season will mean that Aphanomyces will not be a problem this year.  Growers with fields with a history of this disease are encouraged to apply and incorporate precipitated calcium carbonate from sugarbeet factories at 5 to 10 tons per acre in the fall preceding the sugarbeet crop. Soils treated with this product will be protected for over 10 years.

Bruce: 
What can growers do to control Fusarium yellows?

Mohamed: 
Currently, there is no fungicide that will control Fusarium yellows in sugarbeet. As such, growers should ensure that fields with a history of Fusarium should be properly recorded and use Fusarium resistant varieties in those fields. Growers now have access to a large number of Fusarium resistant varieties that are also high yielding with high recoverable sucrose. 

Bruce: 
It has been hot and dry with many days in the 90s. How is Cercospora progressing under these conditions?

Mohamed: 
Temperature over 93 degrees F and dry conditions are not favorable for the development of Cercospora leaf spot. As such, Cercospora has not been a major problem to date and growers have done an excellent job of using fungicides in keeping this disease under control. We now have improved CLS resistant varieties that need less fungicides –this will be a game changer for the industry. My research trials over the past 3 years indicate we can use about 50 to 70% less fungicides with the new varieties to manage Cercospora without impacting yield and quality.

Bruce: 
What can you tell us about Sclerotinia in sugarbeet?

Mohamed:
Sclerotinia sclerotiorum typically causes white mold in soybeans, edible beans, and sunflower. We recently documented that this fungus can also infect sugarbeet leaves as well as roots. Last year, the foliar form of the disease was found in all growing areas of ND and MN. We also found the root form in the disease in both states. The foliar form of the disease is most common and appears to be less damaging than the root infection. I have observed the foliar form of the disease in both ND and MN and need to evaluate how widespread it is. The best way to reduce this problem is to avoid planting sugarbeet the year after soybean, edible beans, or sunflower, especially if these crops had white mold. Much research is needed to understand the biology of this fungus on sugarbeet and how best to manage a new pathogen.
  
Bruce: 
What should sugarbeet growers be doing at this time?

Mohamed:
Growers need to plan management strategy early to manage diseases – planning should start with field and variety selection. Fields with diseases at this time should be recorded so that appropriate varieties and production practices will be used the next time these fields go into sugarbeet. 

Pre-pile will start around the week of August 23and will continue until the full campaign starts in October. Please follow all safety rules at harvest and when transporting and piling beets. Have a good and safe harvest.

Bruce: 
Thanks Mohamed! Our guest this week has been Mohamed Khan, Extension Sugarbeet Specialist at NDSU and the University of Minnesota. 

This has been the Sugarbeet Report. Bringing you the latest information from NDSU throughout the Sugarbeet growing season.