Identifier

etd-11072014-141014

Degree

Master of Science (MS)

Department

Plant Pathology and Crop Physiology

Document Type

Thesis

Abstract

Cercospora leaf blight (CLB) of soybean caused by Cercospora kikuchii is an important disease in Lousiana. Preliminary screening of foliar applications of the micronutrients Fe, Mn, Cu, Zn, B, Mo and Al, showed that Fe decreased CLB severity consistently. The objective of this work was to test the effects of commercial formulations of Fe, Manny Plex Fe and Fe EDTA (Brandt Consolidated, Springfield, IL) on leaf colonization by C. kikuchii, symptom development (blight and purple leaves), and yield. Four rates of Manny Plex Fe and four rates of Fe EDTA were applied to field plots at R5 growth stage. Leaf tissue analyses for microelements and qPCR were performed. Leaf blight and purple leaf symptom severity was assessed quantitatively, and yield was measured. Results showed there was a poor relationship between leaf colonization and symptoms (neither purple nor blight). Moreover, Fe concentration in leaves did not affect biomass of C. kikuchii. Severity of purple leaf symptoms increased as Fe concentration in leaves increased, but severity decreased as Fe concentrations surpassed 230 mg/kg of dry matter. Blight symptoms were suppressed as the Fe concentration in soybean leaves increased. There was no correlation between purple leaf and blight symptoms. There was a positive relationship between leaf concentrations of Fe and yield. Negative relationships between yield and Cercospora biomass and severity of blight and purple leaf symptoms were observed.

Date

2014

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Schneider, Raymond

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