Control Frogeye Leaf Spot with a Fungicide that Uses an Innovative Mode of Action

Published on: 15:14PM Feb 11, 2011

Eric Tedford

Is frogeye leaf spot a problem in your soybean fields? Be proactive in selecting a novel mode of action fungicide in conjunction with recommended practices to better protect soybean fields in the coming months. 
First: Find Frogeye
Frogeye leaf spot is an increasingly problematic fungus for southern states, due to their hot, humid climates, according to Purdue University Extension. When conditions are right, infection can occur at any stage in soybean development and wind can spread the disease from field to field. The most common symptoms of the disease are small, yellow spots which enlarge to lesions of a grayish-brown color encircled in reddish-purple margins. Studies by the Laboratory for Soybean Disease Research at the University of Illinois at Urbana-Champaign show that when these lesions cover roughly 30 percent of the leaf, leaves wither and fall prematurely. The loss of leaves inhibits the plant’s ability to reach full yield potential.
Fight Frogeye with a Systemic Fungicide
You can be proactive and help prevent yield loss caused by diseases such as frogeye leaf spot by applying a fungicide that is systemic and xylem-mobile, meaning the product moves beyond the application site, distributing itself throughout the entire plant. 
Consider a fungicide that contains azoxystrobin as the active ingredient. Azoxystrobin moves systemically through the soybean leaves and provides broad-spectrum disease control and plant physiological benefits that help plants better reach their full genetic yield potential.However, if frogeye leaf spot is the primary disease in your area, avoid the development of resistance by applying a mixture product in order to fight the disease with two active ingredients.
Cultural Practices to Keep in Mind
In addition to using this type of fungicide, also use cultural practices to help manage outbreaks of frogeye leaf spot, such as planting soybeans that are resistant to the disease and rotating/tilling the crops to reduce inoculum. 
What steps will you take this season to manage frogeye leaf spot in your soybean fields?

Eric Tedford, Fungicide Technical Brand Manager for Syngenta, provides technical leadership for the development of fungicides. His experience includes fungicide research and development for field crops, development of postharvest fungicides, and global technical development of fungicides. He holds bachelors, masters, and doctorate degrees in plant pathology from the University of Massachusetts, Clemson University, and the University of California (Davis), respectively.