Evaluation of the Effect of Pyraclostrobin On Soybean Plant Stress.

Strobilurin fungicides control many different plant pathogens including ascomycetes, deuteromycetes, basidiomycetes, and oomycetes. Pyraclostrobin, a type of strobilurin fungicide, has received increased attention because of claims that the chemical improves plant health. These claims suggest that pyraclostrobin allows for more efficient nitrogen uptake, overall better plant growth, and increased tolerance to heat, hail, wind, and drought. Reports of physiological changes from pyraclostrobin include increased leaf greenness, chlorophyll content, and photosynthetic rates. To evaluate these claims, pyraclostrobin will be applied to soybeans at the R3 growth stage (initial pod development) in three Ohio locations. Using a LI-6400XT Portable Photosynthesis System, chlorophyll, fluorescence, and gas exchange measurements will be collected before and after fungicide application. The presence of disease will also be visually evaluated. A statistical analysis will be performed using SAS software, and ANOVA will be calculated. Treatment means will be separated using Fisher’s Protected LSD. Preliminary results indicate pyraclostrobin increased fluroescence ratio at one of three locations.