Once thought to be a disease that only affected western states, Goss’s Wilt outbreaks have increased significantly in Iowa, Nebraska, Wisconsin and Illinois. The increased frequency has prompted many farmers to ask what they can do to avoid Goss’s Wilt in 2012.

Goss’ Wilt is a bacterium that can overwinter in infected residue on the soil surface and in weed hosts. Most often, the bacteria will enter the corn plant through wounds caused by hail damage, insects or even heavy winds. Since Goss’s Wilt is a bacterial disease, foliar fungicides have no effect. Therefore, in-season management options are very limited.

To avoid Goss’s Wilt in 2012, farmers should keep recommended management practices in mind. Best practices include growing resistant corn hybrids, using crop rotation and crop residue management. Choosing corn hybrids with a strong resistance to Goss’s Wilt is your first line of defense, Latham’s own John Toft was quoted in an article posted yesterday by Wallaces Farmer. Other tips to protect fields against Goss’s Wilt are detailed in that same article. Click here to read “Got Wilt? Keep Disease Resistance in Mind.”

Goss’s Wilt, which has plagued Nebraska corn fields since 1969, has been spotted in Iowa this season.  Iowa farmers are searching for ways to protect yield potential yet this season, as well as avoid the problem in 2012, says ISU Plant Pathologist Alison Robertson.

There are three products that Robertson says she’s heard Iowa corn growers are trying to treat Goss’s Wilt: Procidic, Kocide and Intercept.  Procidic is advertised as a broad spectrum fungicide and bactericide.  However, Robertson isn’t aware of any published data for the effect of Procidic against bacterial diseases or use on corn. Kocide is not labeled for use on corn to manage Goss’s Wilt, so Robertson said it should not be used.  A third product that Iowa growers are reportedly trying is Intercept.  There is very little information available on this product, but it’s reportedly been used in Florida to control citrus canker, which is also caused by a bacterium.

Robertson is monitoring a corn field in Gilbert, Iowa, that had an application of Procidic, as well as an earlier application of Stratego YLD. She says she also will be evaluating fields where Intercept has been applied.  At the end of the growing season, ISU researchers will study the effect of both products on Goss’s Wilt disease development and general plant health of the corn.

“Continuous corn production together with minimum tillage practices have in part contributed to the epidemic of Goss’s wilt we are witnessing in 2011,” says Robertson in a recent Wallaces Farmer article.  “Other factors include susceptible germplasm and stormy weather.”

To avoid Goss’s Wilt in 2012, farmers should keep recommended management practices in mind.  Best practices include growing resistant corn hybrids, using crop rotation and crop residue management.

Guest Blogged by John Toft
CCA, Tekemah, NE

Symptoms of Goss’ Wilt were reported earlier this growing season in Nebraska and Iowa.  With all of the storm damage in these areas, including hail and straight-line winds, it’s no wonder that we’re receiving even more reports now of Goss’ Wilt.  Stalk bruising and leaf shredding provide ways for pathogens to enter the corn plant.  High night-time temperatures, which we’ve also experienced recently, favor the spread of Goss’ Wilt.

Goss’ Wilt causes large lesions that start on the leave’s margins and eventually encompass the entire leaf.  These lesions look very similar to Gray Leaf Spot injury.  One simple, but not fool-proof, way to diagnose the difference is that Goss’ will have a waxy appearance due to the different

pathogens that cause the disease.  Gray Leaf Spot is caused by a fungus while Goss’ is caused by a bacterium, which means Goss’ Wilt cannot be controlled by a fungicide.  Effective control measures include crop rotation, tillage and hybrids that show genetic resistance.  Latham’s 2012 lineup has a number of hybrids with excellent disease packages, so keep this in mind as you make your seed decisions in the coming months.

Seed selection is most likely going to play an even more important role as Goss’ Wilt becomes more prevalent.  Bacterial wilt was first reported in Nebraska more than 40 years ago, and the list of states affected keeps growing.  Goss’ Wilt has been identified in Kansas, Colorado, Wyoming, South Dakota and Iowa.  The disease has also been confirmed in Illinois and Wisconsin, according to a NebGuide article, “Goss’s Bacterial Wilt and Leaf Blight of Corn,” published by the University of Nebraska—Lincoln Extension.

Nick Benson, Latham’s corn product specialist for the east, has been seeing Twisted Whorl Syndrome in fields.

This syndrome is most evident in the late V5 to early V6 stages, when corn has five to six visible leaf collars and is about knee-high.  The lowermost leaves appear normal although some may exhibit some crinkled tissue near the base of the leaf blade, according to a newsletter article by Purdue University.  Beginning with the sixth or seventh leaf, the whorl is tightly wrapped and bent over at right angles to the ground.

While the cause of Twisted Whorl Syndrome is not fully understood, there are some correlations between weather.  This phenomenon is more often

present when there has been a sharp transition from periods of slow corn development (typically, cool cloudy weather) to periods of rapid corn development (typically, warm sunny weather plus ample moisture).

There is little or no effect on yield from periods of twisted growth. By the time the affected plants reach waist to chest-high, the only evidence that remains of the previous twisted whorls is the crinkled appearance of the most-affected leaves.

Click the video link below for a short “How To” from Nick Benson on identifying Twisted Whorl Syndrome in your fields.

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