Stewart's Wilt

Stewart's Wilt is a serious bacterial disease of corn caused by the bacterium Pantoea stewartii. This bacterium affects plants, particularly types of maize or corn such as sweet, flint, dent, flower and popcorn. The disease is also known as bacterial wilt or bacterial leaf blight and has shown to be quite problematic in sweet corn in the gram negative state of bacterium. The disease is endemic in the mid-Atlantic and Ohio River Valley regions and in the southern portion of the Corn Belt including parts of the following states: Arkansas, Delaware, Illinois, Indiana, Kentucky, Maryland, Missouri, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia and West Virginia. The occurrence of Stewart's wilt in other eastern and mid-western states, and intermittently in Canada, coincides with the occurrence of the corn flea beetle (Chaetocnema pulicaria), the insect vector and overwintering host of P. stewartii. The primary vector of Pantoea stewartii is the corn flea beetle, (Chaetocnema pulicaria). The bacterium overwinters in the gut of the adult beetle during the winter and come spring, is spread when adult beetles feed on the plant seedlings. The bacteria have also been known to spread from the endosperm of the plant seed to the young seedlings, but this is quite rare and its incidence is insignificant compared to insect transmission. Thus, survival of the insect vector through the winter months, especially in the north central U.S., is the key factor in development of the disease. The disease manifests in two phases: seedling wilt, when the growing point dies; and leaf blight, white lesions on the leaves of older plants. Sweet corn has proven to be more susceptible than field corn, although some hybrids and inbreds of popcorn and field corn are highly susceptible. One of the first forecasting systems designed was for preventing Stewart's Wilt. Apart from forecasting, Stewart's wilt severity can be controlled effectively through use of insecticides and resistant hybrids of corn, with resistant hybrids being the best means of control.