638 
Journal of Agricultural Research 
Vol. XI, No. ia 
On July 7 wound inoculations were repeated (Beldi barley, 4 inches 
high), making a single prick with a very fine needle into a single marked 
leaf on each plant in the pot; plants were transferred to the open garden 
immediately following inoculation, no artificial means being used to 
increase aerial moisture. About 90 per cent of infection resulted. 
In another series of inoculations, in which pot-grown greenhouse plants 
were used, a small drop from a young broth culture of the organism was 
placed on each leaf and the epidermis underneath punctured in one place 
with a fine-pointed needle. The plants were kept in the greenhouse in a 
rather humid atmosphere. Water-soaked infection areas appeared just 
above the pricked spot in four days, one of the shortest incubation 
periods we have noted. This series gave 100 per cent of infection. 
Barley was planted in rows in the open garden on July 15. On July 
22, when the seedlings were about 1 inch high, they were inoculated by 
spraying with a water suspension of pure culture. No shading or cover 
was used, but the weather was moist. On July 28 the first infections 
were noted, an incubation period of six days under normal outdoor con¬ 
ditions. On July 30 the lesions were numerous and typical, with an 
abundance of liquid exudate (PI. 47, A). 
In other cases abundant infections have been obtained by similarly 
spraying older plants (8 to 25 days) in the open without subsequent 
covering. 
These results show that infection is easily secured under normal envi¬ 
ronmental conditions without artificially rupturing the epidermis. It is 
noteworthy that the application of the organisms with the atomizer 
insures better results than wound inoculation. Probably this is due to 
the rapid drying out of the wounded tissues when the puncture method 
is employed. Another interesting outcome is the lesser percentage of 
success where the inoculations were made by direct transfer of the bac¬ 
terial ooze from infected tissues as compared with pure-culture inocula¬ 
tions. This is possibly due in part to the low degree of vitality of the 
organisms in such direct transfer. It may be in part attributed to the 
fact that such ooze hardens very quickly upon exposure, thus imprisoning 
the organisms temporarily at least; and meanwhile the tissues in the 
wounded spot dry out to a degree unfavorable to infection. 
On other grains. —Several trials were made to infect other cereals 
with this organism. Two series of inoculations were run on barley, 
wheat, rye, oats, spelt, emmer (Triticum dicoccum) einkorn (Triticum 
monococcum ), and timothy, and a number of different series on barley, 
wheat, rye, and oats. All gave uniformly negative results except in the 
case of barley which was in every instance heavily infected. Cross¬ 
inoculations with this and other cereal-blight organisms have been 
briefly reported previously (j), and work in connection with these is still 
in progress. 
