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Disease Note. First Report of Stewart’s Wilt of Maize in Louisiana. M. S. Kang, Department of Agronomy, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge 70803. Plant Dis. 71:281. Accepted for publication 1 December 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0281C. Stewart's wilt or leaf blight of maize (Zea mays L.), caused by Erwinia
stewartii (E. F. Smith) Dye, has not previously been reported in
Louisiana. Stewart's wilt can occur on both dent corn (maize) and sweet
corn (1,2). In 1986, a natural infection by E. stewartii of a dent, white-endosperm
inbred line (LJ63) was found in the maize breeding/genetics
nursery at the Perkins Road Farm of the Louisiana State University
Agricultural Center at Baton Rouge. Typical symptoms of Stewart's
wilt, viz., initially irregular pale green to yellow streaks on the leaves
that turned tan to brown as leaf tissue died, were noted. The streaks
originated from feeding marks of the corn flea beetle (Chaetocnema
pulicaria Melsh.). The infection was severe on all LJ63 plants in the
row, with two or three leaves above the ear and all the leaves below the
ear almost completely dead. Bacterial streaming from fresh tissue
samples was observed. This report is of significance because corn is now
a major crop in Louisiana (162,000 ha were planted to corn in 1986-a
78% increase over 1985 acreage).
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