868 
Journal of Agricultural Research 
Vol. XXVII, No. II 
Corn refuse left from a previous crop generally bears an abundance 
of perithecia of Gibberella saubinetii. Morphological examination and 
cross inoculations have proved that this is the same organism as that 
found on scabbed wheat heads. Even though the cornstalks are re¬ 
moved from a field, the remaining corn stubble may show a large number 
of perithecia (PI. i, B, C), unless they are turned under in plowing, 
and it is very difficult to turn them all under (PL i, A). Gibberella 
saubinetii perithecia also have been found on old straw of wheat, rye, 
and oats left on the field (PI. i, D). However, not so much infection 
arises from the ascospores from perithecia on wheat, rye, and oat straw 
because usually the fields are plowed after these crops are grown and 
/=>&£:///ous c/zo/=> 
Fig. i.—G raph showing average percentages of wheat scab following various crops in .1919, 1920, and 1921. 
te* Data summarized in Table V. 
as a result most of the refuse is turned under. Although the greatest 
amount of initial infection probably is caused by overwintering asco¬ 
spores, or conidia formed by the ascospores germinating on the moist 
soil and crop refuse, the mycelium of the organism also may remain 
viable on crop refuse and produce abundant conidia during the following 
spring and summer. Com refuse bears the greatest amount of peri¬ 
thecia because it apparently is a better medium for growth and holds 
the moisture better. Therefore, it is of utmost importance to cut the 
cornstalks close to the ground and remove them from the field if wheat 
is to be seeded on the land. If winter wheat must be sown after corn, 
usually it is not practicable to plow the ground; but, in winter-wheat 
sections especially, if spring wheat is to be sown, such land should be 
fall plowed in order to bury, as far as possible, all com refuse. In all 
