Nov. 1, 1925 
Bacterial Spot of Gowpea and Lima Bean 
861 
Table II .—Tests of commercial cowpea seed samples for the presence of bacterial 
spot infection 
Variety 
Source ° 
Seeds normal in 
appearance 
Seeds shriveled or 
discolored|! 
Number 
of plants 
Number 
infected 
Number 
of plants 
Number 
infected 
Early Red. __... 
A 
14 
0 
32 
0 
Early Black_ __ 
A 
19 
0 
22 
2 
Early Buff _ ___ 
A 
28 
0 
32 
2 
Conch_____ 
A 
12 
0 
20 
0 
Taylor. ___ 
A 
23 
0 
35 
1 
Brabham_ 
A 
28 
1 
37 
0 
California Blackeye. ___ 
A 
23 
16 
2£- 
11 
Vigna catjang___ _ 
A 
18 
0 
34 
2 
New Era. ___ _ 
A 
28 
1 
36 
4 
Do_ _ _ 
B 
13 
0 
19 
0 
Whippoorwill _' _ 
A 
30 
0 
24 
4 
Do ... . . . _ . 
B 
21 
0 
16 
0 
Iron.. _ __ __ 
A 
19 
4 
31 
10 
Do.... 
B 
20 
0 
23 
0 
Groit.. ___ _ 
A 
29 
7 
35 
0 
Do_ 
B 
17 
0 
14 
0 
Red Ripper ___ 
B 
21 
0 
29 
2 
Black. ..... .. _ _ 
B 
24 
o 
21 
1 
Wonderful_ _ . _ 
B 
28 
0 
30 
6 
Clay_ 
B 
26 
6 
23 
3 
a Two sources designated A and B. 
To determine the effect of age of the seed upon the presence of 
bacterial spot infection, 125 plants were grown in sterilized soil in 
the greenhouse in March, 1923, from the same lot of seed of the 
Whippoorwill variety with which the experimental plot had been 
planted in 1921. The disease had appeared in this field plot very 
evidently as a result of seed-borne infection, but did not appear on 
the greenhouse plants grown in 1923. This would indicate that the 
extra two years of storage had eliminated the organisms. 
Table III .—Effect of one extra year of storage on bacterial spot disease transmis¬ 
sion in infected seed in certain commercial seed lots listed in Table 77, determined 
by planting some of the seed in sterilized soil in the greenhouse in March , 1923 
Variety 
Source 
Planted April, 
1922 
Planted March, 
1923 
of seed ° 
Number 
of plants 
Number 
infected 
Number 
of plants 
Number 
infected 
Early Black .. .... 
A 
41 
2 
66 
0 
Early Buff___ 
A 
60 
2 
37 
0 
Vigna catjang_:.... 
A 
52 
2 
131 
0 
New Era____ 
A 
64 
5 
63 
0 
Iron .. .... 
A 
50 
14 
35 
0 
Groit....... 
A 
64 
7 
89 
0 
Red Ripper. ..... 
B 
50 
2 
19 
0 
Wonderful_ _ 
B 
58 
6 
29 
0 
Clay_ 
B 
49 
9 
23 
0 
“Two sources designated A and B. 
The results in Table III indicate that one year of storage had 
eliminated the seed infection in every variety tested. While the 
age of this seed is not known with certainty, it is very probable that 
it came from the 1921 crop. Although these pot tests represent only 
a small number of seed, it would seem that seed two and three years 
old is freer from infection than one-year-old seed, as was found by 
Rapp (15) in the case of bean bacterial blight. 
CEREAL INVESTIGATIONS. 
