STEWART’S DISEASE OF CORN 
By Frederick V. Rand, Pathologist, and Lillian C. Cash, Scientific Assistant, 
Laboratory of Plant Pathology, Bureau of Plant Industry, United States Department 
of Agriculture 
The authors have found Stewards disease (wilt) of corn in Georgia, 
South Carolina, Tennessee, Virginia, Kentucky, Missouri, Iowa, Illi¬ 
nois, Indiana, Ohio, Pennsylvania, District of Columbia, Maryland, 
Delaware, New Jersey, southern New York, and Connecticut. Al¬ 
though in the field the number of diseased plants has usually been un¬ 
der 20 per cent, as high as ioo per cent infection has sometimes been 
found among the earlier varieties. Cultures of the causal organism ( Ap - 
lanobacter stewarti [E F S] McCul.) have been obtained from most of 
the localities where the disease has been observed by the writers. 
The disease was not found in Minnesota, Wisconsin, Michigan, north¬ 
ern New York, Vermont, New Hampshire, and Maine. However, it 
has been reported by other pathologists from Massachusetts, West 
Virginia, Michigan, Oklahoma, New Mexico, and California. 
Seed of 53 varieties of sweetcorn purchased in the open market has 
been planted during three different seasons in Maryland. As one of the 
results of this field study it has been found that an arrangement of 
varieties according to time of maturity coincides almost exactly with an 
arrangement according to percentage of wilt development. The later 
varieties such as Zig Zag Evergreen, Stowell’s Evergreen, and Country 
Gentleman have consistently given a very low percentage of the disease 
(average below io per cent), while the earliest varieties under the same 
conditions have shown a serious loss from wilt (average 25 to 57 per 
cent). In general, wilt prevalence among midseason varieties has been 
between these two extremes. First of All has shown the greatest injury, 
some plantings have given 100 per cent infected stalks, while the Cory 
group, Golden Bantam, and others of the earliest sorts approach it in 
susceptibility. The Evergreen group, as a whole, was little affected; 
and it is interesting to note that Bantam-Evergreen—a cross between 
Golden Bantam and Stowell's Evergreen—appeared to carry with it none 
of the susceptibility of the Bantam parent. Among 45 varieties of field 
com planted during the same three seasons, 32 have at no time shown 
traces of wilt. A few of the dent corns have given 5 per cent or less, 
but it is the earlier flint sorts that have been found most susceptible. For 
example, Will's Gehu has given as high as 65 per cent of infected stalks; 
Square Flint, 40; Longfellow, 22; and King Philip, 19. 
During the past two seasons six experiments relative to soil trans¬ 
mission have been carried out under field conditions. In some cases the 
Journal of Agricultural Research, 
Washington, D. C. 
(263) 
Vol. XXI, No. 4 
May 16, 1921 
Key No. G-233 
