152 
Journal of Agricultural Research 
Vol. XXI, No. > 
CONTROL 
Since the causal organism of bacterial spot is carried with the seed, 
seed disinfection at once suggests itself as a control method. 
Inasmuch as the fruit lesions are superficial, there is no probability 
that the bacteria are inside the seed, and all evidence points toward their 
being carried on the exterior of the seed. The fruit lesions contain 
millions of the bacteria, and the processes of extracting the seed afford 
ample opportunity for surface contamination of the seed with the bac¬ 
teria from these lesions. The surface of a tomato seed is covered with 
long cellulose hairs which increase immensely the surface for lodgment 
of the organisms and prevent their removal by washing. Laboratory 
tests have proved that the organisms will endure long periods of desic¬ 
cation on seed. Surface disinfection of the seed should eliminate the 
disease-producing bacteria. 
A number of tests were made to determine what method of disinfection 
might be safely applied to tomato seed. Small quantities of tomato 
seed were tied up in gauze bags. Before being placed in the disinfecting 
solution each bag was immersed about a minute in 50 per cent alcohol 
to remove air bubbles from the hairy seed coats. After disinfection the 
seed samples were dried, and portions were submitted to the local Federal 
seed laboratory for germination tests. Part of the samples were tested 
in soil. The results are presented in Table VIII. 
Xabi.t? VIII .—Effect of seed disinfection on vitality of seed 
Seed 
sample 
No. 
Treatment. 
Percentage 
of germina¬ 
tion in offi¬ 
cial test. 
Percentage 
of germina¬ 
tion in soil 
flats. 
87-5 
72 
I 
TTcrPl_ t* 0 one c minutes . 
94 - 5 
96- 5 
96- 5 
95 
80 
2 
1 AtiVt'xrA c% t n/sr pptif ? TTlt till . 
3 
rormaiaenyue x per cent, 5 ... # • • • 
TJmrnol/lplivHp 0 tier pptit c minutes 
92 
4 
ronnaiucuyuc 2 pci vuiij 5 ... 
Pnntrnl untreated .. 
96 
9 
xi/fPI t • t onn t minutes . .. ..••i******** 
62. 5 
85 
87 
87 
86 
5 
a 
XTrrCM t • r% nAA P* till tlllfpC .. 
0 
rlcVi-jrrlo r CPtlt f miniltPS . 
7 
8 
10 
13 
14 
1 5 
T f\ 
ronnamcnyuc 1 pci cent, 5 nuuuivo. ...• * • 
I?Artnn 1 / 1 olrtr^ 1 o nPf PPtlt f ttlltllttPQ .. 
Pntitfnl untreated .... 
Tinrr'i^ t • 5 000 c minutes... 
88 
86 
Uorpr t • a non c minutes... 
90 
87.5 
86.5 
74 - 5 
89- 5 
89 - 5 
68 
79 
TTrrPI t • r r\ r\r\r\ tf TTli till tPS ... 
Tfr*rmaidetivde o C tier pent TO mmuteS. ... . ,. 
81 
10 
rl nil 'i r/^1 ck o p trAf* PAtlf tf ttlinilteQ at ....... 
*7 
t q 
ronnaiuciiyue 2.5 pci ccutj j umiutva • 
T?nrmaldeVivde c tier cent. K minutes.... 
81 
10 
19 
TJnrtriQlHplivHp to tier cent c minutes . ... 
88 
JCUllIlcllUCiiyUC Av pci vviity 3 U1AAAu * • • • .. • • 
Tint water cc° C . io minutes... 
49 
20 
<9 T ■ 
Control untreated. 
85 
/ 80 
i 1 O A 
1 X 
11 80 
From these figures it is evident that treatment in mercuric chlorid 
1 to 1,000, in hot water, and in hot formaldehyde is injurious to ger¬ 
mination. None of the cold formaldehyde treatments resulted in 
