TECHNICAL SESSION: Epidemic analysis
Relationship Between Sudden Death Syndrome caused by Fusarium virguliforme and Soybean Yield: A Meta-analysis
Yuba Kandel - Iowa State University. Daren Mueller- Iowa State University, Martin Chilvers- Michigan State University, Albert Tenuta- Ontario Ministry of Agric & Food, Kiersten Wise- University of Kentucky, Carl Bradley- University of Kentucky, Febina Mathew- South Dakota State University, D
A total of 57 uniform field experiments conducted in Illinois, Indiana, Iowa, Michigan, Wisconsin, and Ontario Canada from 2013 to 2017 comparing crop protection products against SDS were analyzed using meta-analytic models to summarize the relationship between foliar disease index (FDX) and yield. For each study, correlation and regression analyses were performed separately to determine three effect sizes: Fisher’s transformation of correlation coefficients (Zr), intercept (?0) and slope (?1). A random- and mixed effect meta-analysis was used to summarize the effect sizes. Study- and location-specific moderator variables; foliar disease level (FDX; low < 10%, high ? 10%), date of planting (early = prior to 7 May, optimum = 7 May – May 21, and late = after 21 May) cultivar (susceptible and partially resistant to SDS), study location, and year were used as fixed effects. The overall mean effect sizes of r (the back transformed Zr) was -0.39 and different from zero (P < 0.001) indicating yield was negatively correlated with FDX. Zr was affected by disease level (P < 0.01) and cultivar (P < 0.02) with a greater effect in higher disease levels and with susceptible cultivars. The mean 0 was 4121 kg/ha and mean 1 was -21 kg/ha/% and were different from zero (P < 0.01). For every unit of FDX increase yield will decrease by 0.5%. Study locations and year affected the ?0 while none of the moderator variables significantly affected ?1 .