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United States Department of Agriculture

Agricultural Research Service

Research Project: BREEDING SELECTION AND MOLECULAR CHARACTERIZATION FOR IMPROVED SUGAR BEET GERMPLASM

Location: Sugarbeet and Bean Research

Title: Lack of interaction between glyphosate and fungicide treatments on Rhizoctonia crown and root rot in glyphosate-resistant sugarbeet

Authors
item Barnett, Kelly -
item Sprague, Christy -
item Kirk, William -
item Hanson, Linda

Submitted to: Journal of Sugar Beet Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 24, 2011
Publication Date: June 1, 2011
Citation: Barnett, K.A., Sprague, C.L., Kirk, W.W., Hanson, L.E. 2011. Lack of interaction between glyphosate and fungicide treatments on Rhizoctonia crown and root rot in glyphosate-resistant sugarbeet. Journal of Sugar Beet Research. 48:1-16.

Interpretive Summary: A field experiment was conducted in 2008 and 2009, in the Saginaw Valley region of Michigan to determine if there were potential interactions between applications of an herbicide, glyphosate, and a fungicide, azoxystrobin, and to determine the effectiveness of foliar and in-furrow azoxystrobin applications for managing Rhizoctonia crown and root rot of sugar beet. Significant differences in disease indices, percentage of harvestable sugarbeet, and percentage of healthy sugarbeet were evident among the different varieties and fungicide treatments, but herbicide treatment did not significantly affect these parameters. Foliar applied fungicide resulted in the lowest disease index (2.0) and highest percentage of healthy sugarbeet (42%) when compared with the no fungicide treatment (disease index 5.9, 1% healthy sugarbeet). In-furrow fungicide treatment reduced the disease index when compared with no fungicide. The herbicide did not affect the efficacy of fungicide treatments, but choosing a disease-tolerant variety and applying foliar fungicide applications appear to the best methods for managing Rhizoctonia crown and root in glyphosate-resistant sugarbeet.

Technical Abstract: A field experiment was conducted in 2008 and 2009 in the Saginaw Valley region of Michigan to determine if there were potential interactions between applications of glyphosate and the fungicide azoxystrobin and to determine the effectiveness of foliar and in-furrow azoxystrobin applications when Rhizoctonia solani is present. Significant differences in disease indices, percentage of harvestable sugarbeet (Beta vulgaris L.), and percentage of healthy sugarbeet were evident among the different varieties and azoxystrobin treatments, but herbicide treatment did not significantly affect these parameters. Hilleshög 9027RR and Hilleshög 9029RR had the lowest disease indices and highest percentage of healthy sugarbeet when compared with Crystal RR827 and Hilleshög 9028RR. Foliar applied azoxystrobin resulted in the lowest disease index (2.0) and highest percentage of healthy sugarbeet (42%) when compared with the in-furrow application or no fungicide treatment. In-furrow azoxystrobin reduced the disease index when compared with no fungicide. Similar trends were observed for harvestable sugarbeet, except for Crystal RR827 where there was not a significant difference between in-furrow azoxystrobin and no fungicide. Glyphosate did not affect the efficacy of fungicide treatments, but choosing a Rhizoctonia-tolerant variety and applying foliar fungicide applications appear to the best methods for managing Rhizoctonia crown and root in glyphosate-resistant sugarbeet.

Last Modified: 9/20/2014
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