222 
Journal of Agricultural Research 
Vol. XXIV. No. 3 
Tabi^^ XVI .—Inoculation with miscellaneous organisms 
Experi¬ 
ment 
No. 
Date of inoculation. 
Variety and age of host. 
Organism. 
Gum¬ 
ming. 1 
Death of 
bark.i 
I 
Nov, 23,1912 
Lemon, 19 years.. 
Alternaria sp. from in¬ 
I 
X 
jured fruit. 
2 
Feb. 25,1913 
Lemon, 2 years.... 
Alternaria sp. 
0 
I 
3 
May 24,1912 
Lemon 16 years... 
Coprinus atramentarius, 
0 
0 
mycelium. 
4 
.do. 
.do. 
Spores of same. 
2 
I 
5 
July 13.1913 
Lemon, 19 years... 
Coprinus atramentarius 
2 
I 
mycelium. 
<3 
May 24,1912 
Lemon, 16 years... 
Hypholoma sp. spores. .. 
I 
0 
7 
Aug. 3,1912 
Lemon, 16 years 
Hypholoma sp. myce¬ 
I 
0 
(2 trees). 
lium. 
8 
Sept. 25,1912 
Lemon, 19 years... 
Cladosporium sp. 
0 
0 
0 
.do.. 
.do. 
Rhizopus sp. 
0 
0 
lo 
Sept. 4,1913 
Lemon, 18 years... 
Penicillium digitatum. .. 
0 
0 
11 
Aug. 3,1912 
Lemon, 16 years... 
Diplodia sp. 
2 
I 
12 
Nov. 23,1912 
Lemon, 19 years... 
Spegazzinia ornata . 
0 
0 
13 
July 13,1913 
_.do. 
Coryneum berynkii from 
2 
I 
peach. 
14 
.do._ .... 
Orange stock, 
I 
0 
same tree. 
15 
July 12,1912 
Lemon, 19 years... 
Pseudomonas cerasius 
0 
0 
Griffin. 
16-25 
.do. 
.do. 
10 different cultures of 
0 
0 
bacteria • inoculated 
from bark killed by 
gummosis. 
Controls, without inoculum to correspond with each of the foregoing 
0 
0 
experiments. 
^ o=»none, i=slight, 2=»meditmi. 
The results show that several different organisms are usually capable 
of inducing the formation of a small quantity of gum and a limited 
amount of injury to cells adjoining a wound when inserted into cuts on 
sound tissue but are without any noticeable effect in producing definite 
diseases. This gum formation or death of tissue was, in these cases, as 
well as with Fusarium sp., and Penicillium roseum, insignificant in 
amount as compared with that produced in cases of either Pythiacystis 
or Botrytis gummosis. 
PART III.—GUM FORMATION AND ITS RELATION TO THE 
DEVELOPMENT OF DISEASES 
INTRODUCTION 
In Parts I and II of this paper the relation of certain fungi to definite 
diseases in which gum formation was a conspicuous feature has been 
discussed. It was shown experimentally that the most destructive types 
of gum diseases on Citrus in California in which there is progressive dying 
of tissue over large areas are due to fungus invasion. Fungi, however, 
are not necessary to mere gum formation, since it has been shown that 
other agencies, such as chemical injections, may induce gum formation in 
the absence of microorganisms. 
