Goss's Bacterial Wilt and Leaf Blight
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Symptoms of Goss's Wilt
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)
Facts
- 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.
Goss’s Wilt Disease Development
- 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
Disease Cycle
Goss’s Wilt Management
- 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.