Once inside the leaf tissue, the bacterium multiplies in the vascular tissues and initiates the characteristic leaf symptoms. The severity of Stewart's bacterial leaf blight can be predicted based on the temperature of the preceding winter months. A severe outbreak of leaf blight generally occurs when the sum of the average temperatures for December, January, and February is greater than 95. When the sum of the average temperatures for these months is less than 90, the amount of disease is usually negligible. This forecasting system is based on the ability of the corn flea beetle to survive overwinter.
Cold winters reduce beetle populations and limit disease development and spread.
Environmental conditions, like persistent snow cover and heavy crop residues, may favor beetle survival even with low winter temperatures. These conditions should be considered when forecasting disease outbreaks. Control All sweet corn varieties are susceptible to wilt in the first leaf stage. A few are resistant by the second leaf stage and many are resistant in the third and fourth leaf stage. Dent corn hybrids are more resistant to wilt than sweet corn.