A Stem Blight oe Field and Garden Peas 
13 
whether the remaining’ nine cultures, whicli were isolated at the 
same time, were likewise responsible for the disease and still viru¬ 
lent, each of nine Horsford plants was inoculated with a 48 -ho'ur 
agar culture of the respective organisms, to-wit: One from stem 
(No. i), two from petiole (No. 2 ), two from petiole (No. 3 ), two 
from leaf blade (No'. 4 ), two from stem (No. 5 ). 
In this case, the bacteria were introduced intO' the stems by 
single shallow needle pricks about i centimeter apart and were dis¬ 
tributed over the younger part of the vine. In addition tO' this, 
several leaves on each plant were punctured and the culture smeared 
over the injured leaf surface. All plants were sprayed with sterile, 
distilled water immediately after inoculation, covered with bell jars 
and placed in subdued light. They were sprayed again after 36 
hours, and after 48 hours they were uncovered and placed in the 
greenhouse. 
Ohsci'vations 
After four days, each of the inoculated plants shows a decided 
watery zone around each needle prick in the stem, and all of the 
leaf infections except the one made with culture from Stem No. 5 
are taking perfectly; the leaves appear watery and bruised not only 
around the needle puncture, but also in isolated spots where the cul¬ 
ture was rubbed over the surface; this suggests stomatal infection. 
The disease seems to be progressing most rapidly in the plant that 
was inoculated with one of the cultures isolated from the leaf blade. 
(No. 4 -) 
Dec. I, Ip 13. —^The watery, bruised appearance of the leaves is 
spreading and in some cases the leaves are beginning to curl. 
Dec. 5 , 1915 - —The stem pricks now show up as sunken yellow 
areas, 3 mm. long. 
Dec. 6 , 1913 . —Stems now dark olive-green and watery, not 
only around the needle pricks, but continuous over the entire stem 
where inoculated. 
Dec. y, 1913 . —Reisolation made from plant inoculated with 
culture isolated from leaf blade q. v. page 18 . 
March 31 , 1916 . —All inoculated shoots brown and dead ; four 
plants are entirely destroyed and have thrown out no new growth 
from below; one plant has two new shoots, while the remaining 
three have one each; none of these is vigorous, due possibly to other 
causes. Check normal. 
Inoculations of Dec. 17 , 1915 . —Horsford Peas 
Nine different cultures, presumably all the same organism, 
picked up from colonies which were obtained by plating out tissue 
from a plant infected in the laboratory November 25 with a pure 
