Pantoea stewartii

Stewart's wilt
The corn flea beetle is the vector of Stewart's wilt
Causal agents	Pantoea stewartii
Hosts	maize
Vectors	corn flea beetle (Chaetocnema pulicaria)
EPPO Code	ERWIST

P. s. subsp. stewartii
P. s. subsp. indologenes

Pseudomonas stewarti (sic) Smith 1898
Bacterium stewarti (Smith 1898) Smith 1911
Aplanobacter stewarti (Smith 1898) McCulloch 1918
Phytomonas stewarti (Smith 1898) Bergey et al. 1923
Xanthomonas stewarti (Smith 1898) Dowson 1939
Pseudobacterium stewarti (Smith 1898) Krasil’nikov 1949
Erwinia stewartii (Smith 1898) Dye 1963

Stewart's wilt is a serious bacterial disease of corn caused by the bacterium Pantoea stewartii. This bacterium affects plants, particularly types of maize 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. The disease is endemic in the mid-Atlantic and Ohio River Valley regions and in the southern portion of the Corn Belt.

Stewart's wilt can be a serious disease of many corn types, including: sweet, dent, flint, flower, and popcorn. Sweet corn and popcorn cultivars are more susceptible to Stewart's wilt than field (dent) corn, but some dent corn inbreds and hybrids are susceptible. The production of virulence factor can be caused by the communication system between the bacteria known as quorum sensing. Stewart's wilt causes yield reductions by decreasing the size of corn stand or by limiting its production, resulting in fewer and smaller ears of corn.

The disease is seen in parts of Arkansas, Delaware, Illinois, Indiana, Kentucky, Maryland, Missouri, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. Its occurrence in other eastern and Stewart’s wilt has two phases of symptoms: the wilt phase and the leaf blight phase. For both phases, symptoms first appear as leaf lesions, initiating from corn flea beetle feeding scars. At first, the leaf lesions appear long and irregularly shaped and are light green to yellow and later on, straw colored. On mature plants, yellowish streaks with wavy margins extend along the leaf veins. This leaf blight phase is often prevalent after tasseling and the symptoms look similar to frost damage, drought, nutrient disorders, northern corn leaf blight (caused by Exserohilum turcicum), and particularly Goss's wilt (caused by Clavibacter michiganensis ssp. nebraskensis). A good way to determine if the corn is facing symptoms from Stewart's wilt is to look at the leaf tissue under microscope. If the bacterial ooze exhibits nonflagellated, nonspore-forming, rod-shaped bacteria, the likelihood of Stewart's wilt is great.