Plant Health Initiative

Cercospora Leaf Blight - Management

Crop rotation and residue management are important control measures for Cercospora. Photo creidt: SS Navi, Iowa State University

A combination of cultural controls and host resistance can provide good control of Cercospora:

• Crop rotation to minimize pathogen build-up
• Residue management, such as tillage, to promote the rapid decomposition of infected residue and destruction of the pathogen.
  In no-till or reduced-till systems, longer crop rotations and shredding soybean straw with a combine-mounted shredder are effective.
• Plant disease- free seeds
• Plant varieties with some resistance to Cercospora. Later-maturing cultivars are also more resistant than early-maturing cultivars.
  
• Field location and plant spacing that allows for good air flow
• Field location with good soil drainage
  

Possibilities for chemical control

Seed lots with a high percentage of infected seed can be treated with a seed treatment fungicide.
Foliar fungicides may be applied during early pod stages R3-R5 in fields with a history of the disease, or when weather conditions are especially conducive..