NDSU Extension - Griggs County


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November 6

Extension Connection column by Jeff Stachler

Goss’s Wilt

Good day!  There is still some corn to harvest in the county as of last Friday.  Corn is only about 95% harvested.  Finally Indian Summer arrived, so hopefully all field work will get finished.  I will be gone through November 11th to harvest some research trials I had started back in Ohio.  I will still be available by phone and email if you need something.

The number one corn disease in North Dakota is Goss’s Wilt!  I did not realize that as it was just getting started when I was in North Dakota before.  I was told that in 2020 Goss’s wilt was found in 65% of scouted corn fields in North Dakota.  That is a serious problem.  I’m not sure how prevalent it is in Griggs County, but it is obviously present.  It was reported to me that NDSU found very high incidences of Goss’s wilt in Steele County in the last two years!  Yield losses from Goss’s wilt and blight can exceed 30 percent for susceptible hybrids.

The causal agent for Goss’s wilt is a bacteria named Clavibacter michiganensis subspecies nebraskensis.  Since it is a bacteria, fungicides will not control this disease!  The bacteria overwinters on infested corn debris near the soil surface.  It is possible that the bacteria may be transmitted by seed at very low levels.  Other grass species such as grain sorghum, sudangrass, several foxtail species, shattercane, and eastern gamagrass are also susceptible to the bacteria, allowing the disease to be more prevalent.

To identify this disease look on the corn leaves for elongated tan lesions having irregular margins and extending parallel to the veins.  It looks similar to northern corn leaf blight.  Large sections of the leaf can be affected.  Within the lesions, dark, water-soaked spots can develop.  In addition look for shiny patches of dried bacterial ooze that appears similar to dried varnish on the lesions.  Where infection occurs on the stalk, orange vascular bundles may appear inside the stalk.  When the bacteria enters the leaf when the plant is a seedling it can wilt and cause death of the seedling.  This is called the blight phase and it does not occur very often.  To confirm the presence of the disease look for signs and symptoms on the leaves, bacterial streaming from the lesions using a microscope and confirmation of the presence of the bacterial pathogen.

For the disease to develop certain conditions must occur.  The bacteria usually infects leaves that have been wounded by such things as hail, sand-blasting, rain, wind, and strong storms.  After infection the disease spreads throughout the plant and can spread from plant to plant.  Disease development is favored by warm (greater than 80 degrees F) conditions.  Symptoms are most often visible and increase in severity after silking.  Planting susceptible hybrids, reducing tillage, and planting corn-on-corn favors the disease.

Management options are limited!  The best management tool is to plant resistant corn hybrids.  So as you are choosing corn hybrids for next season only ask for hybrids resistant to Goss’s wilt.  Tillage after harvest to bury the residue and controlling grassy weeds can reduce the presence of the bacteria.

Have a great weekend!

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