Distinguishing features of Goss’s Wilt lesions

• Freckles – dark green to black water-soaked spots, often near lesion edges (white arrows)
• Shiny exudate – bacteria ooze to leaf surface and may appear shiny after drying (black arrows)

• Disease is caused by a bacterial pathogen that overwinters in residue of corn and several grasses
• Historically, damage to corn had been confined mostly to the Great Plains states
• In recent years, significant crop damage has also been reported in central Corn Belt states
• Depending on conditions, may cause only minor problems or devastating damage with grain yield losses approaching 50%

Historical and current range of Goss's wilt in North America.

• Plant wounding from wind, sandblasting and especially hail provide openings for bacteria
• Insects are not known to be a factor in spread or development of this disease
• Wet weather and high humidity encourage development
• There are two phases of the disease
  • Systemic wilt (less common)
  • Later season foliar blight

Systemic Wilt Phase

• Less common than foliar phase
• Can cause large losses, especially in susceptible hybrids
• May cause a slimy stalk rot, especially in seedlings
• May cause plant death
• Plants wilt due to vascular infection with bacteria
• Vascular bundles may have orange coloration that turns brown to black after disease progresses

Later Season Foliar Blight

• Water-soaked streaks may appear first followed by gray or brown/tan lesions
• Lesions are elongated with wavy margins that follow leaf veins
• General lesion shape may resemble Stewart’s Wilt lesions
• Foliar lesions may progress to foliar blighting, killing large amounts of the canopy and predisposing plants to stalk rots

• Genetic resistance
  • Primary management method
  • Pioneer researchers inoculate, screen and rate hybrids for resistance
  • Hybrids are also rated under natural infestations in affected states
  • See your local Pioneer sales professional for help in selecting appropriate hybrids for your field
• Reduce corn residue
  • Disease can become problematic in corn on corn, high-residue fields
  • Crop rotation is effective in reducing residue
  • Tillage encourages residue breakdown
• Control grassy weeds that are hosts for the bacteria
  • Green foxtail, barnyardgrass, shattercane and others
• Prevention/Avoidance
  • Harvest and till affected fields last and clean equipment to avoid spreading the pathogen to uninfested fields
• Fungicide application IS NOT EFFECTIVE for this bacterial disease. Other materials are being tested.