*eb. 34 .1923 Early Vigor , Yield , and Diseases of Maize 
585 
the greater yields. Kyle (2d) found that com plants making a vigorous 
early growth gave greater yields than those that were weak in their early 
stages of development. Grantham (14) studied the development and 
maturity of 100 hills of com where a weak plant was growing with a 
vigorous one. From 50 of the hills he removed the weak plant and from 
50 others he removed the vigorous plant. Measurements taken at dif¬ 
ferent dates showed that the vigorous plants made the most rapid early 
growth and the greatest yield of shelled corn per plant. The vigorous 
plants tasseled on the average about nine days earlier than the weak 
plants. 
From time to time various investigators have attributed the cause of 
slow and irregular growth in maize to the influence of pathogenic 
organisms. Burrill (3) in discussing a bacterial disease of com said: 
The first indication of the disease in a field of com, as noticed in ordinary observation, 
is the dwarfed condition of the young plants. 
Duncanson (8) noted that diseased plants were dwarfed, slender, and 
generally unhealthy. Stewart (57), working with sweet com (Zea mays 
saccharata ), noted that— 
usually, the small plants are the first to succumb to the disease, which fact suggests 
that the disease may be the cause of their slow growth. This suspicion was confirmed 
by microscopic examination. Plants green and apparently healthy except for their 
small size, were found to contain a considerable quantity of the bacterium in their 
vessels, while in the larger, more vigorous plants, the bacterium could not be found. 
However, in wet weather the bacterium may sometimes be found in quite vigorous 
plants. 
Selby (34) noted conditions similiar to those described by Burrill. 
Later he (55) stated that the root rot of com caused a dwarfing of the 
plants and a failure of the stalk to produce an ear. Hoffer and Holbert 
(15) pointed out that the use of diseased seed com was one of the causes of 
high percentages of blighted and stunted plants and subsequent un¬ 
satisfactory yields. Rosen (32), in describing a bacterial disease of 
com, noted that the diseased plants could be recognized easily by the 
short, stunted nature of the stalks. Holbert, Dickson, and Biggar (16) 
conducted experiments in which half of the hills were inoculated at 
planting time with a pure culture of Gibberella saubinetii (Mont.) Sacc. 
They summarized their results as follows: 
In the inoculated hills germination was lowered, earlyjgrowth retarded, relative 
vigor during the season reduced, and grain production lessened. 
The pathogene with which they were inoculated was readily recovered 
from the diseased plants during the seedling stage. They stated further 
that— 
Plants, strong or weak in the early stages of growth, had a tendency to retain this 
relative vigor throughout the season. Average grain production was directly correlated 
with rate of early growth and early vigor. 
Trost and Hoffer (38) found that starchy ears of com of certain dent 
(varieties produced larger numbers of weak-growing and root rot sus¬ 
ceptible plants in the field and yielded less per acre than the plants from 
ears of more homy composition, irrespective of whether or not the starchy 
kernels were infected with Fusarium spp. before planting. 
Baker (2), Butler (4), Palm (29), Rutgers ( 33 ), and others working in 
the Orient have found that the downy mildews (,Sclerospora spp.) in 
attacking young maize plants, cause a serious stunting in their early 
growth. Plants so affected seldom produce grain. A complete descrip¬ 
tion of this disease is given by Weston (59). 
