Feb. 2 4 ,1923 Early Vigor ,. Yield , and Diseases of Maize 
623 
diseased. Although the complete data and discussion regarding these 
experiments are reserved for other publications, a limited number of 
these data are presented in Table XXVII to show the influence of seed 
infection and susceptibility to the root and stalk rots to total yield and 
yield of marketable com, with special reference to the percentage of 
rotted ears. 
The field stand data (Table XXVII) are of particular interest. Many 
investigators would consider a field stand of 92.5 to 95.8 per cent a 
satisfactory stand. These stand data lend further emphasis to the fact 
that satisfactory field stands are no guarantee against losses due to the 
root, stalk, and ear rot diseases. 
TabtE XXVIII .—Summary of data presented in Table XXVII, showing percentages 
of rotted ears and yield of marketable corn 
INFESTED SOII, 
Condition of seed. 
Early planting. 
Tate planting. 
Yield of 
marketable 
corn. 
Rotted 
ears and 
nubbins. 
Yield of 
marketable 
corn. 
Rotted 
ears and 
nubbins. 
Selected composite of susceptible seed. 
Nearly disease-free composite. 
Bushels. 
SO . 0 
69-3 
Per cent. 
34.9 
17. 7 
Bushels. 
39 ' 7 
59-3 
Per cent. 
40 - 5 
25. 0 
ctean SOII, 
Selected composite of susceptible seed. 
42 - 5 
32.5 
55-2 
37 * 0 
Nearly disease-free composite. 
73 -0 
19. 0 
81.6 
16. 0 
Although there was a consistent reduction in total yield in the com 
grown from the diseased, susceptible seed, the greatest and most im¬ 
portant differences were in the yields of sound, marketable com and the 
percentages of rotted ears. These items are summarized in Table 
XXVIII and figures 18 and 19. In both plantings and on both infected 
and clean soil the corn grown from diseased, susceptible seed produced 
more rotted ears and a much lower yield of marketable com. The 
bushel weights indicate that the marketable com produced by the nearly 
disease-free seed was of better quality than that produced by the dis¬ 
eased, susceptible seed. 
The results secured at Urbana, reported in Table XXIX and figure 20, 
were obtained from com grown from the same moderately diseased and 
nearly disease-free seed composites as the date-of-planting experiments 
conducted at Bloomington, reported in Tables XXI to XXV. The soil, 
however, was much higher in fertility than that of the Bloomington 
plots; in fact, the Urbana soil was in a better state of balanced fertility 
than the average Com Belt soil will be for several years. The standards 
for classifying the plants into vigorous, semi vigorous/and weak were 
based entirely on height measurements. Plants from the moderately 
diseased seed were grouped into three approximately equal divisions 
according to height. This same standard when applied to the plant 
populations from nearly disease-free seed gave relatively high percentages 
of vigorous plants and low percentages of weak plants. 
