PLATE 6 
Relation of date of seeding to the development of seedling-blight of Marquis wheat. 
A. —Wheat plants from inoculated, scabbed, and clean seed sown April 22, when 
the soil temperature was below 12 0 C. Note the uniformly good stand from all three 
lots of seed. 
B. —Wheat plants from inoculated, scabbed, and clean seed sown May 10, when 
the soil temperature was above 12 0 C. Note the greatly reduced stand from the 
inoculated seed and especially from the scabbed seed. 
C. —Root development of wheat sown April 22. Left, uninoculated; right, inocu¬ 
lated with Gibberella saubinetii. Note the large root systems in each. 
D. —Root development of wheat sown May 10. Left, uninoculated; right, inocu¬ 
lated with G. saubinetii. Note that the root development is much less extensive 
than on the plants from the April 22 seeding shown in C. See E for the detailed 
comparison of the root systems. 
E. —Root systems of the four lots of spring-wheat plants shown in position in C and D. 
Each bundle contains the roots of five plants. (1) Sown April 22; left, uninoculated; 
right, inoculated. (2) Sown May 10; left, uninoculated; right, inoculated. Note 
the reduction in root systems in (2) right, inoculated seed sown May 10, when the 
mean soil temperature was above 12 0 C. In contrast, note the lack of reduction in 
(1) right, where the seed was inoculated and sown April 22, when the soil temperature 
was below 12 0 C. 
