Stewart’s Bacterial Wilt is more severe on young plants than on older plants. Symptoms appear first on leaves. Pale green to yellow streaks with wavy margins may extend the length of the leaf. These streaks usually change from pale green to yellow or brown starting at feeding scratches made by the corn flea beetle (Chaetocnema pulicaria). On young plants, brown discoloration and sometimes cavities may form in the pith at the center of the stem near the soil line. At its worst, rotted cavities can result in severe stunting, wilting or death. While early-infected plants may die, late infected plants may be only stunted or have streaked leaves. Infected plants sometimes produce premature, bleached and dead tassels.
The disease-causing bacterium overwinters in flea beetles and is spread to corn plants. Warm winters favor overwintering of flea beetles and usually precede seasons when Stewart’s Bacterial wilt is prevalent. Flea beetles
carrying the bacteria can be expected if the sum of the average monthly temperatures for December, January and February exceeds 90*F.
Controls
Cultural: Early control is most critical because seedling infections of highly susceptible hybrids are often lethal.Plant wilt-resistant hybrids such as Apache, Comet, Comanche, Gold Cup, Incredible, Miracle, Sweet Sue,
Seneca, Sentry and How Sweet It Is.
Chemical
Monitoring: Watch for infestations of flea beetles.
Application: See information about flea beetles under "Insect Pests
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