The increasing presence of Goss’s bacterial wilt is casting a shadow on 2012 corn prospects. Since 2008, Goss’s bacterial wilt and blight which was first observed in Nebraska corn fields in 1969, has spread across the primary corn-growing states.
The most important fact to remember about Goss’s bacterial wilt is that it is a bacteria and not a fungus. Goss’s bacterial wilt is caused by the bacterium, Clavibactermichiganensis subsp. Nebraskensis, and occurs either as leaf blight or vascular wilt on corn plants.
Accurate and early identification of Goss’s bacterial wilt is critical. The increasing threat of Goss’s bacterial wilt is causing growers to proactively identify the disease and protect corn crop yields. It has two distinct phases: a leaf blight phase and a systemic wilt phase. Leaf blight is the most commonly observed and most damaging symptom and usually appears mid-season. Lesions extend along leaf veins and first appear as long, gray-green water-soaked streaks with wavy margins. Smaller, darker water-soaked flecks, often referred to as freckles, are apparent inside the larger lesion.Corn plants in the systemic wilt phase will show drought stress symptoms and wilt or die prematurely.
Watch the Purdue University video about identifying Goss’s bacterial wilt in corn. Because the symptoms are easily confused with other diseases, it’s important to have careful field examination or to send a sample into your local plant pathology lab to confirm the diagnosis.
As the incidence of Goss’s bacterial wilt increases, so do crop losses. A drop of 60 bushels per acre is possible with a severe infestation of the bacterial wilt, according to Engage Agro USA executives quoting plant pathologists. The company reported a discussion with Alison Robertson, an Iowa State University Extension pathologist, and it quoted her as estimating that in 2011 Goss’s bacterial wilt caused $60M in Iowa crop losses. However, the company says some field agronomists think the Iowa loss may have been two or three times this amount.
No methods are available to control Goss’s bacterial wilt; therefore, preventing or reducing infection with good foliar nutrition is essential, according to Engage Agro USA. A well-balanced nutrient program using a product to provide plants with additional nutrition during peak demand periods and to correct imbalances before yield loss occurs is the company’s prescription. Whether the disease is already present in a corn field or not, applying a foliar nutrient such as the company’s 42PHI Cu, a copper based fertilizer, can help ward off further infection and promote new growth and yield, the company claims.