Corn disease outlok & management
In the Furrow
By Will Duffie

Tropical weather this past weekend has brought much relief to cropland across Burke County.

Was this rainfall too late for the dryland corn crop? We'll have to wait and see. These types of

weather systems

can often be responsible for bringing diseases our way. Therefore corn growers are urged to scout fields for foliar diseases.

Corn historically has not received attention when it comes to disease control with fungicides. In 2002 and 2003 many corn fields in Georgia saw heavy infestations of southern rust. From 2003 to 2006, seven on-farm research studies were conducted by Extension Agents in Burke, Jenkins, Seminole & Terrell counties.

The results from these studies are as follows: Only one of the seven trials had a statistically significant yield response to a foliar fungicide due to disease. In the trial with a positive response, Southern Rust pressure was extremely heavy. One trial in 2006 had a minimal response in the absence of disease.

Here are a few items that I have learned from these studies. First of all that fungicides are excellent management tools to manage diseases on an as needed basis. Scout corn hybrids that are susceptible to diseases prior to tassel or when the corn plant has around 14 to 15 leaves. The primary diseases are southern rust and southern corn leaf blight.

Remember that diseases tend to build in high yield environments. Such environments that will increase plant leaf include high plant populations, increased nitrogen fertility, and irrigation. Once disease has been identified in a field or area, make a timely application with a labeled fungicide. In general, fungicides should be applied from tassel through silking. In years where disease pressure is intense, a second fungicide application may be warranted.

As far as diseases other than southern rust, research data shows that it was difficult to show a significant yield benefit on any corn variety infected with common corn rust or southern corn leaf blight. For more information call the UGA - Burke County Extension Office at 706-554-2119.