2023 Verona, MS Soybean Variety Trial Frogeye Leaf Spot Evaluation Ratings

Frogeye leaf spot lesions as observed in the upper most foliage.

The entries contained in the 2023 Mississippi State University Official Variety Trials (OVT) were evaluated for their reaction to several important plant diseases during the 2023 season.  Disease severity differed across locations and as a result some locations had little to no disease present.  The OVT location at Verona, MS; however, served as the best information for the response of the entries contained in the OVT to frogeye leaf spot.  A total of 11 locations were conducted during 2023, with Verona as the only location with enough frogeye leaf spot to make observations.   The trials at Verona consisted of three row plots of each variety, replicated three times and included all of the entries in the OVT (MG IV early and late, MG V early and late, MG IV and V Enlist) for a total of five sets of entries within each MG.  Observations of each variety were conducted using a modified 0-9 scale whereby all of the plants in the corresponding plot were observed at one time and the value that was given was based on the plot of each variety exhibiting disease.  Frogeye leaf spot generally occurs in the upper third of the canopy.  Observations were made at approximately R6 or shortly thereafter and values presented are the average of each of three replicate plots for each variety.  Be mindful, that in some cases, the true level of susceptibility may differ at a given location and the environment that occurs during the season will contribute to the response of a variety.  As stated above, Verona was the best location for observing frogeye leaf spot during 2023.  I won’t make broad statements about whether something is “susceptible” or “resistant” based on these data as presented since overall frogeye leaf spot levels were low (even at Verona).  But, with that said, if a given variety scores a 4 (as an example), and the remainder of the varieties appeared to have less frogeye leaf spot, then I would suspect the variety with the 4 to be more “susceptible” than the remainder of the varieties.

Xtend varieties:

Maturity Group IV Early 2023 FLS MG IV early Xtend

Maturity Group IV Late 2023 FLS MG IV late Xtend

Maturity Group V Early 2023 FLS MG V Xtend

Maturity Group V Late 2023 FLS MG V late Xtend

Enlist varieties:

Maturity Group IV and V Enlist 2023 FLS MG IV Enlist