Poster Session: Cultural Control

246-P

Effects of minor elements on Cercospora leaf blight of soybean and production of cercosporin.
B. M. WARD (1), C. Robertson (1), R. Schneider (1), E. Silva (1), S. Albu (1)
(1) Louisiana State University Agricultural Center, Baton Rouge, LA, U.S.A.

Cercospora kikuchii is the causal agent of both Cercospora leaf blight (CLB) and purple seed stain in soybean. CLB, which appears late in the season and is exacerbated by high temperatures, is a serious disease of soybean in Louisiana. Yield losses of 10 to 15 percent are common, and complete crop failure may occur under severe conditions. The disease is currently managed by early planting and fungicide applications; however, fungicide protocols are still being evaluated to determine the most efficacious materials and times of application. In addition, evidence suggests that the pathogen is developing resistance to many of the currently used fungicides. Furthermore, disease resistant varieties often succumb to the disease after a few years. Previous experiments have shown that some minor elements, including iron, aluminum, and zinc, may suppressed disease symptoms. This study investigated the effects these and other minor elements on in vitro cercosporin production. Furthermore, the possible siderophore-like activity of cercosporin and other fungal metabolites was examined using mass spectrometry and other analytical techniques.