There are three key decisions you can make to prevent Goss’s wilt from infecting your corn this year.
The first decision, and one that can be made long before spring arrives, is to rotate to a non-host crop such as soybeans or edible beans. If you do plan to rotate be sure to remember that neighboring fields can be greatly affected due to infected corn residue blowing and moving to adjacent fields.
Second, good tillage practices (plowing is most effective) will reduce the presence of the disease in years to follow. Burying the infected crop residue minimizes the potential for disease survival and infection the following year.
The third, and one of the most important decisions to make when planning your corn acres, is selecting corn hybrids with high tolerance to Goss’s wilt.
Fungicides provide very little help fighting Goss’s wilt. If found in a field, there is little that can be done to manage the disease in the current growing season, which is why it’s vitally important to take the steps to prevent the disease before it happens. Choosing corn hybrids with the highest possible tolerance and rotating to a non-host crop such as soybeans or edible beans into your planting plan are two ways to stop Goss’s wilt before it starts.
Signs and symptoms
A corn plant can show two different symptoms of Goss’s wilt: systemic plant wilt and leaf blight. Leaf blight is most commonly observed with initial symptoms of what looks like dark green or black water-soaked spots on the leaf, commonly referred to as freckling. As the disease progresses, the bacteria on the leaf will ooze, leaving a shiny, varnished look after it has dried. Later, oblong sections of dead plant tissue will be observed on the leaf.
The disease can also infect the vascular tissue and move systemically throughout the plant, but this is less common in the north. A systemic infection is identified by splitting the stalk and observing vascular discoloration or stalk rot. A systemic infection of Goss’s wilt will more than likely lead to plant death.
Goss’s wilt survives and overwinters on corn residue which is why it is often found in fields that are corn following corn. Goss’s wilt will infect the plant through an open wound anywhere on the plant. These wounds often are caused by hail and high winds.
Scouting should be done throughout the growing season and corn should be monitored closely if the disease is discovered. Once confirmed, using a drone to assess the severity and size of the affected area is helpful. It is easy to see the brown, infected areas and to determine how many acres are affected.Kyllo is an agronomist with Peterson Farms Seed.