If there was an award for corn disease of the year, Goss's Wilt looks to be the runaway winner. In 2011 Goss' Wilt has expanded its footprint across much of the Corn Belt. The disease was first observed in Nebraska more than 40 years ago. For much of that time, the disease seemed to be content in Nebraska but beginning in 2008 it began to march eastward into Iowa, Illinois and Indiana. Its movement east was aided by the westerly winds that have dispersed the inoculum across the I-states, most notably Iowa and Illinois. The map detailed in Figure 1, was put together by AgriGold agronomists and details where Goss's wilt is most prevalent in 2011.
 

Where Is It?
 
Figure 1. Where is it? 2011 map of Goss's wilt and its disease severity across the corn belt.
 
Red-Severe infestation
Orange- Moderate infestation
Yellow- Low infestation
 
 

Disease Development and Identification
The pathogen overwinters in crop residue and serves as the primary inoculum source. As the young plants are damaged by wind, hail or heavy rain the bacterium enters in and can cause two types of symptoms. The most common symptom is water-soaked lesions that appear on the leaf and glisten in the sunlight. Goss's wilt lesions tend to have wavy or bleeding margins between healthy and diseased tissue as seen in Figure 2. The foliar lesions can progress and kill large areas of the canopy thus significantly reducing the photosynthetic capacity of the plant. The other, less common symptom occurs when the xylem tissue within the stalk becomes discolored and slimy causing the plant to conduct water less effectively. Loss of photosynthetic area coupled with compromised stalks may warrant early harvest due to the possibility of stalk cannibalization.
 
Figure 2. Goss's Wilt Leaf Blight. Notice the shiny, water soaked appearance with wavy/bleeding margins.
 
Effects on Yield
Yield losses have been documented from both the wilt and leaf blight phases of the disease, however it has been difficult to quantify.   We know that Goss's Wilt favors high humidity along with warm temperatures of at least 80°F. Likewise hot, dry temperatures can impede disease development.  
 
Currently, no research has been conducted on the effect of ensiling on the survival of Goss's wilt. It would be exposed to higher temperatures, other microorganisms and lower pH. In prior studies of other closely related bacterium it has been documented that these three factors all negatively impacted their survival. Thus the high temperature, microorganisms and low pH present in the ensiling process should also be expected to reduce the survival of Goss's Wilt. At this present time there is no known risk to feeding infected silage to livestock.