2016
Optimizing the Use of Irrigation, Row Spacing, Partial Host Resistance and Fungicides for Management of Sclerotinia in Soybeans
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Contributor/Checkoff:
North Dakota Soybean Council
Category:
Sustainable Production
Keywords:
Crop protectionDiseaseField management
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Michael Wunsch, North Dakota State University
Co-Principal Investigators:
Pravin Gautam, North Dakota State University
Leonard Besemann, North Dakota State University, Carrington Research Extension Center
Tyler Tjelde, North Dakota State University-Williston Research Extension Center
+2 More
Project Code:
Contributing Organization (Checkoff):
North Dakota Soybean Council
(n/a)
Institution Funded:
North Dakota State University, Carrington Research Extension Center
(n/a)
Brief Project Summary:

Irrigated field trials at Carrington, Hofflund (Nesson Valley), Langdon, and Oakes, ND to confirm key findings from 2014, including the following: (1) sharp reductions in Sclerotinia can be achieved without reducing the overall amount of irrigation applied if a higher amount of water is applied in each irrigation event and the number of days between irrigation events is increased; (2) optimal application timing for foliar fungicides is the early R2 growth stage unless the canopy is still open, in which case fungicide efficacy may be optimized by delaying applications several days; (3) a single fungicide application may be sufficient even under very high disease pressure, with a low application...

Unique Keywords:
#soybean diseases
Information And Results
Final Project Results

Updated December 2, 2016:
Final Progress Report is downloaded in the File (optional) below

View uploaded report Word file

Optimizing the use of irrigation, row spacing, partial host resistance, and fungicides for management of Sclerotinia in soybeans

Michael Wunsch1, Michael Schaefer1, Billy Kraft1, Suanne Kallis1, Leonard Besemann2, and Heidi Eslinger2, Venkat Chapara3, and Amanda Arens3

1NDSU Carrington Research Extension Center, 2NDSU Langdon Research Extension Center, and 3NDSU Robert Titus Research Farm

The objective of this multi-year project is to develop agronomic recommendations that significantly improve soybean yield and Sclerotinia control under high white mold disease pressure. When conditions are favorable for white mold, current management strategies often do not confer satisfactory control of white mold (Sclerotinia) in soybeans.

Field trials conducted in 2014 and 2015 suggest that the current recommendation of applying fungicides at the R1 growth stage (bloom initiation) may not be optimal when targeting Sclerotinia. Across 11 field trials conducted across multiple soybean varieties and diverse environments, delaying applications of the fungicide Endura from the R1 to R2 growth stage improved Sclerotinia disease control from 25% to 44% and increased the yield response to the fungicide application from 5.3 bu/ac to 8.1 bu/ac. Results were similar when Endura was applied at 5.5 oz/ac and 8.0 oz/ac. When soybeans were seeded to narrow rows (7 to 15 inches apart), applying Endura at the early R2 growth stage (80 to 98% of plants with an open blossom at one of the top two nodes) was optimal; when soybeans were seeded to intermediate and wide rows (21 and 28 inches apart), applying Endura at the full R2 growth stage (100% of plants with an open blossom at one of the top two nodes) was optimal.

Research initiated in 2015 suggests that seeding soybeans to wide rows (28 inches apart) may not optimize soybean yield even under high white mold disease pressure. Across eight soybean varieties evaluated in Carrington, five varieties evaluated in Oakes, and three varieties evaluated in Langdon at three seeding rates (132,000; 165,000; and 198,000 viable seeds per acre), soybeans seeded to wide (28-inch) rows consistently developed less white mold than soybeans seeded to narrow (7- and 14-inch) and intermediate (21-inch) rows. However, even under high white mold disease pressure, yields were optimized when soybeans were seeded to rows 14 and 21 inches apart. If producers who can tolerate slightly increased levels of sclerotia in the harvested grain, the results suggest that seeding soybeans to rows 14 and 21 inches apart might be optimal even when the risk of Sclerotinia is high. Results from 2015 also suggest that row spacing may have a much stronger influence on Sclerotinia disease development than seeding rate.

Research on these research questions and related research questions is continuing in 2016, and revised recommendations cannot be developed until multi-year testing is completed. However, findings from research conducted in 2015 suggest that it may be possible to significantly increase soybean yields under high white mold pressure with modifications to current recommendations.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.