First Look: 2015 North MS Research and Extension Center Soybean Disease Ratings (EDITED)

Frogeye leaf spot (FLS).

Included in this blog update are the foliar disease ratings from the North MS Research and Extension Center.  The publication that includes yield will be added in another blog post at a later date.  The variety trials located at the North MS Research and Extension Center in Verona, MS were rated for the presence and severity of Cercospora leab blight, frogeye leaf spot, Septoria brown spot, and where present target spot.  In addition, green stem was observed in the Maturity Group IV early and late varieties.  Frogeye leaf spot ratings were conducted using a 0-9 scale where 0=no disease and 9=severe disease.  Cercospora blight was also rated using a 0-9 scale; however, a 9 is characterized by purple pods, petioles, and stems while a 5 would be indicative of the disease only being present on leaf tissue.  Both Septoria brown spot and target spot were rated using a scale of 0-9; however, the scale was used a bit differently since both diseases are typically observed lower in the canopy.  A 0=no disease, while a 1 indicates disease presence on the lowest leaves, a 5 would be indicative of disease present in the middle canopy while a 9 would indicate either Septoria brown spot or target spot in the upper most plant canopy resulting in severe defoliation.  Green stem, when this malady was able to be rated, was rated on a scale of 0-100% and indicates the presence of green stem within the entire plot based on the percentage scale.

The abbreviations used in the tables below are as follows:

CLB=Cercospora leaf blight (late-season Cercospora)

FLS=frogeye leaf spot

Septoria=Septoria brown spot

Target spot=target spot
Maturity Group III (Verona MG III varieties) NOTE: multiple plots of the same variety were planted in some cases with different seeding rates.

Maturity Group IV Early (Verona MG IV early varieties)

Maturity Group IV Late (Verona MG IV late varieties)

Maturity Group IV Conventional/Liberty Link (Verona MG IV conventional-libertylink)

Maturity Group V Early (Verona MG V early varieties)

Maturity Group V Late (Verona MG V late varieties)

Maturity Group V Conventional/Liberty Link (Verona MG V conventional-libertylink)