In The Field Now: Powdery Mildew and Rhizoctonia Applications

Published online: Jul 01, 2009 Pest and Crop Alerts
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Powdery Mildew in Sugarbeets Treasure Valley - Idaho As of June 25, 2009, Amalgamated Sugar Company Field Representatives are advising growers that now is the time to plan treatments for powdery mildew in sugarbeets. While mildew has not yet been found in the Treasure Valley, White Satin Field staff say the modes of action of the mildew chemistries work best if treatments are applied before mildew is found in the field. They are recommending mildew applications in the west end of the Treasure Valley the week after July 4 regardless of whether or not fields are surface or sprinkler irrigated. They also advise including an insecticide treatment for black bean aphid or loopers in the mildew tank mix. Pest alert brought to you by Jerry Neufeld at The Treasure Valley and Pacific Northwest Pest Alert Network ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ North Dakota State University Rhizoctonia Applications Crop & Pest Report As of June 18, 2009, Dr. Mohamed Khan, extension sugarbeet specialist with North Dakota State University and University of Minnesota: -"Rhizoctonia solani can infect all growth stages of sugarbeet and may cause wilting and death of plants." -"Rhizoctonia crown and root rot are becoming more widespread and disease severity appears to be increasing." -"Rhizoctonia crown and root rots need to be managed since they cause significant yield reduction." Dr. Khan's Recommendation: Fungicides Proline or Quadris "in a 7-inch band at the 4-6 leaf stage" or when the soil temperature is 65-68 degrees F four inches below the surface. Earlier this spring Dr. Khan predicted Rhizoctonia to be as troublesome for growers in 2009 as Cercospora leaf spot - a Red River Valley regular. Historically Rhizoctonia crown and root rot was not a major problem in the Red River Valley. Kevin Thorsness, technical service representative for Bayer CropScience: "Rhizoctonia has moved to the front of everybody's mind as growers shift from conventional to newer varieties that offer benefits in weed control but appear more susceptible to the disease." -Few fungicides offer activity on Rhizoctonia. -Proline fungicide from Bayer CropScience is the only fungicide with protection against all three major sugarbeet diseases-Cercospora, Rhizoctonia and powdery mildew. -Proline offers excellent crop rotation flexibility and tankmix compatibility with most insecticides, herbicides and fungicides. For information on Rhizoctonia and its growing prevalence in the Red River Valley, please contact: Kevin Thorsness Technical service representative Bayer CropScience 701-293-0653 office 701-238-9497 cell