12 
Bulletin 84. 
teria which appear identical. Eight check twigs punctured at the tip with a 
sterile knife show no sign of disease. 
"M Pure cultures of the bacteria from the three sources, apricot 
fruits, apricot twigs and apple twigs were secured as soon as pos¬ 
sible with which further inoculations were made. Plain neutral 
potato agar was used in making poured plates from which trans¬ 
fers were made to tubes of potato agar, potato plugs and sugar 
beet plugs. Inoculations were made July 7 with the pure cul¬ 
tures into apple fruits and apple twigs as given in the following 
tables: 
TABLE I. 
Inoculations of Apples with Cultures of Bacteria Secured from Diseased Apri¬ 
cot Twigs, Apricot Fruit and Apple Twigs. 
No. of 
Experiment. 
No. of 
Apples. 
Sources of 
Cultures. 
Date of 
Inoculation. 
Date of 
Examination. 
Results. 
No. 4. 
5 
Apricot Twigs 
July 7 
July 28 
All discolored and shrivelled. 
No. 5. 
5 
Apricot Fruit 
July 7 
July 14 
Negative. 
No. 6 . 
6 
Apple Twigs 
July 7 
July 28 
One fruit black and shrivelled. 
No. 7 . 
6 
Check 
July 28 
Sound. 
No. 8. 
6 
Apricot Fruit 
July 14 
July 28 
Five fruits shrivelled and discolored. 
Evidence of the success of the inoculations became apparent in some in¬ 
stances on the third day. (Fig. 1.) There being no development of disease in 
any of the apples in Experiment No. 5, further inoculations were undertaken on 
July 14, as indicated in Experiment No. 8, using another tube of the same culture. 
Final notes were taken on July 28. The five fruits in Experiment No. 4 inoculated 
with culture from apricot twigs all discolored and shrivelled. Experiment No. 
5 gave negative results, probably due to weak or dead culture material. No. 6, 
using a culture of known pear blight taken from a blighting apple limb, one 
fruit black and shrivelled; the other five gave negative results. No. 7, check 
apples, all sound. No. 8, inoculated with culture from apricot fruit, five apples 
shrivelled and blackened over most of their surface. One showed no evidence 
of disease 
TABLE Ft 
Inoculation of Apple Twigs with Cultures of Bnctoria Secured from Disused 
Apricot Twigs, Apricot Fruits and Apple Iwigs 
No. of Experiment. 
No. of 
Twigs. 
Source of 
Culture. 
Date of 
Juoculation. 
jH 
o 
24-1 
CD g 
cd ^ 
r - 
r ~’ cz 
KN 
w 
Results. 
No. 9. 
7 
Apricot twigs. 
July 7 
July 29 
Five twigs diseased. 
No. 10. 
7 
Apricot fruit. 
July 7 
July 29 
All twigs diseased. 
No. 11. 
5 
Apple twigs. 
July 7 
July 29 
All twigs diseased. 
No. 12. 
6 
Check. 
July 29 
Sound. 
