The bacterium m can enter the stalk, resulting in bleached, dead tassels and decayed cavities in the stalk tissue. When cut, infected stalks may ooze droplets of pale yellow bacteria. In susceptible sweet corn, systemic infections can cause rapid wilting and death of the plant any time before tasseling. Control Most cultural practices do not influence Stewart's disease because the pathogen survives in the flea beetle. Weed control may have some effect because the insects prefer grassy weeds and damage to corn is highest in weedy fields.
Most hybrids are resistant enough that no further management is required.
If flea beetle numbers are extremely high, and insecticide applications can reduce the beetle population and the disease spread. This will occur only after a very mild winter. In seed production with susceptible inbreds, an insecticide may be justified more often. Corn flea beetle and feeding scars on corn Figure 25. Stewart's disease spreading from the flea beetle feeding scars Figure 26.