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Managing and Understanding Goss's Wilt

With the 2016 growing season just around the corner, farmers everywhere are preparing their cropping strategy to ensure a successful season. As we move forward, considerations must be made to address some of the challenges that might be faced in this upcoming year. In 2015, farmers across the Corn Belt experienced many challenges including weather extremes and disease. Unfortunately, we have not figured out how to control the weather. However, with proper management tactics we can reduce or even control the yield limiting effects of crop diseases.

One disease in particular that has raised questions over that past few summers has been Goss’s wilt ( Clavibacter michiganenisis subsp. Nebraskaenesis ). Goss’s wilt was first confirmed in Nebraska in the late 1960s and has been found in most states throughout the Corn Belt since then. Being a bacterial disease means cultural practices and hybrid selection are critical for control, since fungicides are ineffective.

A corn plant can show two different symptomologies of Goss’s wilt, which is a systemic plant wilt or leaf blight. In most cases the leaf blight is more commonly observed. Identifying the disease can be difficult as it tends to look like other foliar disease such as northern corn leaf blight and Stewart’s wilt. Initial leaf blight symptoms include 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. Progressing even further, 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. A systemic infection can be identified by splitting the stalk and observing vascular discoloration or stalk rot. A systemic infection of Goss’s wilt can lead to plant death. The University of Nebraska reported systemic infection can infect the plant at any time during the growing season and under severe instances can cause up to 50 percent plant loss.

Because Goss’s wilt survives and overwinters on corn residue, this disease is more commonly found where corn after corn is common practice. Goss’s wilt will infect corn through an open wound anywhere on the plant. These wounds can be caused by hail, high winds and insect feeding. Farmers who commonly grow corn after corn and are located in the western Corn Belt should be actively managing for this disease. It should be scouted for in more eastern production areas as well, but will likely be a less common management issue. Scouting for Goss’s wilt should be done throughout the growing season, and monitored closely if the disease is discovered.  

Since Goss’s wilt is a gram-positive bacteria, there are no pesticides currently available that will provide control. If Goss’s wilt is confirmed on your farm there is little that can be done to manage the disease, however, you can begin making decisions for the following year. The first option that can greatly reduce the presence of the disease is to rotate to a non-host crop such as soybeans or alfalfa. Tillage is another management practice that can reduce the presence of Goss’s wilt. Tilling the soil buries infected crop residue, which reduces the potential for disease survival and infection the following year. The third line of defense is selecting corn hybrids with high tolerance to Goss’s wilt. In some instances it may referred to as resistance, but there is no true resistance to this disease. To properly place and select Goss’s tolerant hybrids, please get in touch with your Beck’s field representative and they will work together with your Beck’s field agronomist to select and place the proper hybrids to combat Goss’s wilt on your farm.  

Identification of the disease can be difficult and should be sampled and sent to a lab for confirmation. If you suspect that Goss’s wilt or any disease may be present in any of your fields, please feel free to contact your Beck’s field agronomist and we will be happy to help you identify the disease and provide the best management practices for combating the issue.  

Wade Kent, Field Agronomist

For more agronomic news, check out the February issue of Beck’s CropTalk Newsletter.

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