Soybean Yield Loss to Diseases in the Midsouthern US, 2016
Members of the Southern Soybean Disease Workers Group participate in an annual survey to estimate yield losses to soybean diseases in the southern US. These estimates are solicited from research and extension pathologists throughout the region, and are based on field surveys, plant disease samples, variety trials, questionnaires to Extension Specialists, research plots, grower demonstrations, private crop consultant reports, foliar fungicide trials, and sentinel plot data. Production losses are based on estimates of yield in the absence of diseases.
Below are summary results from the 2016 crop year survey conducted in the midsouthern US.
• Diseases and nematodes caused estimated soybean yield losses of 9.1%, 16.0%, 14.3%, 7.6%, and 14.2% in Arkansas, Louisiana, Mississippi, Missouri, and Tennessee, respectively.
• An estimated 76.2 million bushels of lost soybean yield was attributed to diseases and nematodes in the collective states, with a value or $762 million using a $10/bu commodity price.
• In the 2016 growing season, the most damaging pests across the five states (in descending order of caused yield loss) were soybean cyst nematode (SCN), root knot nematode (RKN), frogeye leaf spot (FLS), charcoal rot (CR), and cercospora leaf blight (CLB).
• In Arkansas, diseases/pathogens causing the most yield loss were RKN, CR, FLS, and CLB.
• In Louisiana, diseases/pathogens causing the most yield loss were CLB, RKN, reniform nematode (RN), FLS, and Rhizoctonia aerial blight (RAB).
• In Mississippi, diseases/pathogens causing the most yield loss were CR, RN, CLB, Septoria brown spot (SBS), FLS, and RKN.
• In Missouri, SCN and sudden death syndrome (SDS) caused most of the yield loss to diseases/pathogens.
• In Tennessee, FLS, SCN, seedling diseases, SBS, and CR caused most of the yield loss.
• CR and CLB were significant damaging diseases across all years in all states except Missouri.
• SCN and SDS contributed most to yield loss in Tennessee and Missouri.
• Yield loss attributable to RKN only occurred in Arkansas, Louisiana, and Mississippi, and yield loss attributable to RN only occurred in Louisiana and Mississippi.
• FLS was a significant damaging pest in all states, and this may be associated with the increasing resistance of the FLS pathogen to fungicide control.
• Yield losses to viruses and bacterial diseases were 0 or negligible in all 5 Midsouthern states.
• The 0 or negligible yield loss to stem canker in all states is testimony to the effectiveness of varietal resistance as a control measure to avoid yield loss to a fungal pathogen since there are no efficacious fungicides for the stem canker pathogen.
• The negligible effect of seedling diseases on estimated yield loss in most states is testimony to the effectiveness of fungicide seed treatments against seed rot and seedling disease pathogens.
Click here for the survey results from each year during the 2011-2016 period, a summary of the results from the annual surveys conducted during the 6-year period in the Midsouth, and the raw data used in each year’s calculations.
Composed by Larry G. Heatherly, Mar. 2017, larryheatherly@bellsouth.net