Stewart's wilt

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Cornfleabeetle

Stewart's wilt is a bacterial disease that affects corn (Zea mays). It is caused by the bacterium Pantoea stewartii subsp. stewartii. The disease is named after Franklin Stewart, who first described it in the late 19th century.

Symptoms

The primary symptoms of Stewart's wilt include leaf blight and wilting. Infected plants exhibit long, wavy, yellow to brown streaks on the leaves. These streaks are often accompanied by a slimy bacterial ooze. As the disease progresses, the leaves may wilt and die, leading to significant yield loss.

Disease Cycle

Stewart's wilt is primarily spread by the corn flea beetle (Chaetocnema pulicaria), which acts as a vector for the bacterium. The beetles acquire the bacterium by feeding on infected plants and then transmit it to healthy plants during subsequent feedings. The bacterium can also survive in the beetles over the winter, allowing the disease to persist from one growing season to the next.

Management

Effective management of Stewart's wilt involves a combination of cultural practices, resistant hybrids, and insect control. Key strategies include:

• Planting resistant hybrids: Selecting corn varieties that are resistant to Stewart's wilt can significantly reduce the impact of the disease.
• Controlling the corn flea beetle: Insecticides can be used to manage beetle populations and reduce the spread of the bacterium.
• Crop rotation: Rotating corn with non-host crops can help break the disease cycle.
• Sanitation: Removing and destroying infected plant debris can reduce the source of inoculum for the next growing season.

Economic Impact

Stewart's wilt can cause significant economic losses in corn production, particularly in regions where the corn flea beetle is prevalent. Yield losses can be severe in susceptible hybrids, making disease management a critical component of corn production in affected areas.

Research

Ongoing research aims to better understand the biology of Pantoea stewartii and its interaction with the corn flea beetle. Advances in genetic engineering and plant breeding are also being explored to develop more resistant corn varieties.

See also

• Corn diseases
• Plant pathology
• Bacterial diseases of plants