Stewart's wilt

Stewart's wilt, technically known as bacterial wilt of corn, is a destructive plant disease caused by the bacterium Pantoea stewartii. This pathogen specifically targets the vascular tissue of the corn plant, leading to systemic infection that severely compromises the plant's ability to transport water and essential nutrients.

The primary host for this disease is corn (Zea mays), with sweet corn hybrids being notably more susceptible than most field corn varieties. When the infection occurs early in the growing season, it can cause devastating losses, potentially leading to total crop failure in highly sensitive cultivars.

Symptoms are categorized into two phases: the seedling phase, which features rapid wilting and stunted growth, and the leaf-blight phase. The latter is characterized by long, wavy-edged yellow streaks running parallel to the leaf veins. As the disease progresses, these lesions dry out, turn brown, and the leaf tissue dies prematurely.

The transmission of Pantoea stewartii is primarily mediated by the corn flea beetle (Chaetocnema pulicaria). The bacteria survive the winter months within the gut of the adult beetles. Once temperatures rise in the spring, the beetles emerge and feed on young corn plants, transmitting the pathogen directly into the vascular system.

Effective management strategies center on the selection of genetically resistant corn hybrids, which remains the most reliable defense. Additionally, producers should employ integrated pest management (IPM) to control flea beetle populations during the early vegetative stages, as well as monitor weather patterns to anticipate high-risk seasons following mild winters.

• Wavy, chlorotic leaf streaks.
• Systemic wilting of young plants.
• Bacterial oozing from vascular bundles.
• Premature leaf necrosis.
• Reduced yield and quality of harvest.