Stewart's bacterial wilt

Stewart's bacterial wilt is a destructive plant disease caused by the bacterium Pantoea stewartii. This pathogen colonizes the xylem of the host plant, disrupting water uptake and transport, which eventually causes the plant to wilt and collapse under severe infection pressure.

The primary host for this pathogen is maize (corn), with sweet corn varieties being particularly susceptible. The disease can affect the crop at any growth stage, leading to significant yield losses or total crop failure depending on the timing of the infection and the susceptibility of the hybrid.

Symptoms appear as long, wavy-edged yellow or light-green streaks on the leaves that parallel the leaf veins. In later stages, these lesions turn brown and necrotic. A diagnostic feature is the presence of sticky bacterial ooze visible on the surface of leaf cuts, and potential yellowing or darkening of the vascular bundles within the stalk.

The main vector for transmission is the corn flea beetle (Chaetocnema pulicaria). The bacterium overwinters inside the gut of the adult beetle. As the beetles feed on corn leaves in the spring, they introduce the bacteria into the plant tissue through their mouthparts and feeding wounds.

Effective management strategies primarily focus on the use of resistant corn hybrids, which is the most reliable method for controlling the disease. Integrated pest management, including the application of insecticides to control flea beetle populations during the early stages of corn development and crop rotation, helps to minimize the risk of bacterial spread.