RHIZOCTONIA ROOT AND CROWN ROT CONTINUES TO BE THE MOST SERIOUS YIELD ROBBING DISEASE OF SUGARBEETS. In spite of drier conditions in 2012 Rhizoctonia incidence was common and disease moderate to severe in many fields. Great strides have been achieved in reducing Rhizoctonia incidence and severity, but there are still unacceptable losses in many fields.
Samples of diseased roots are analyzed for root rot problems each year at the U of MN, NWROC diagnostic lab. Rhizoctonia has been the most severe problem in both a wet year (2011) and a dry year (2012), see figure one.
* Results may total more than 100% if multiple diseases are diagnosed in a single sample.
Every management option must be utilized to achieve success. American Crystal Sugar Company growers greatly increased utilization of IPM options between 2010 and 2012. Carefully evaluate past options used on your farm and determine where improvement is possible. Your management plan for moderate to severe Rhizoctonia should include:
Diagram courtesy J. Brantner, UM, NWROC
Your method of fungicide application is critical to successfully controlling Rhizoctonia. Assuming a 5 inch wide leaf area for a 4-6 leaf plant means broadcast application of fungicide places a high percentage of POST applied pesticide on the soil between the row, see Figure 3.
How much product is on the targeted plants depends on your application method. Band apply to maximize value of your expensive fungicide for best disease control, Table 1.
Table 1: Effect of Application Method on Amount of Fungicide Hitting the Plant - Brantner and Windels, U of MN, NWROC.
|Application Method||Amount of Product Hitting the Row*|
|Application Rate (fl oz./A.)|
|5 - inch band||5 (100%)||7.5 (100%)||10 (100%)||14.5 (100%)|
|7 - inch band||3.6 (72%)||5.4 (72%)||7.1 (72%)||10.4 (72%)|
|11 - inch band||2.3 (46%)||3.8 (46%)||5.0 (46%)||6.6 (46%)|
|Broadcast||1.1 (23%)||1.7 (23%)||2.3 (23%)||3.3 (23%)|
* Assumes a 5 inch wide canopy for a 4-6 leaf sugarbeet
"You have a choice, each choice has consequences" Jeff Stachler, NDSU/UM Extension Sugarbeet Weed Specialist.
The time for action is NOW. Next year or 2014 may well be too late. Spend a little now or pay a great deal later.
"He that is good at excuses is seldom good for anything else". This quote is especially pertinent to taking action against weed resistance now."
Contact your Agriculturist to develop a complete crop rotation weed resistance management plan for your farm.