TREATMENT OF CELERY SEED FOR THE CONTROL OF 
SEPTORIA BLIGHT 1 
By Webster S. Krout 
Assistant Research Professor of Botany , Massachusetts Agricultural Experiment Station 
Septoria blight is often traceable to the use of infected seed. In a 
study of control measures at this point an obvious line of attack is 
through seed disinfection., It is a simple matter to kill spores on the 
surface of the seed by superficial disinfection. However, many infected 
seeds have spores in pycnidia embedded in the pericarp, and an attempt 
to kill these with a chemical disinfectant would endanger the vitality of 
the seed. 
Statements from seed dealers and growers that many celery growers 
use seed 2 or 3 years old suggested the possibility that the spores of 
Septoria on and in the seed might not remain viable for so long a period. 
This indicated a second line of attack. 
Accordingly, the problem of control was approached along two lines: 
(a) A study of the effect of aging the seed on the vitality of the spores 
and mycelium of Septoria; (6) the use of hot water as a disinfectant. 
The results are presented in this paper. 
EFFECT OF AGING CELERY SEED ON THE VITALITY OF SEPTORIA 
SPORES 
Conidia taken from celery leaves or from the surface of the seed and 
stored under the usual laboratory conditions were dead in from 8 to 11 
months from maturity. Conidia from the peduncles and pericarps of 
seed gave a 2 to 3 per cent germination at the end of 2 years but were 
always dead at the end of 3 years. Spores from i-year-old seed were 
slightly more viable than those from 2-year-old seed. Germ tubes of 
spores from 2-year seed were few and slow in developing, 8 days being 
the minimum time of appearance. Other results indicate that spores 
dried for 1 or 2 years in the pericarp of seed lack the vigor to produce 
germ tubes capable of penetrating the tissues of healthy celery plants. 
It should be stated that the mycelium in the leaves, on the seed, in the 
seed, and in the peduncles of the seed was dead at or before the time 
herein reported for the death of the spores. Therefore, no reference has 
been made to the age at which the mycelium died. The germination 
tests of conidia and mycelium were conducted in the field during the 
1 Published with the approval of the director, Massachusetts Agricultural Experiment Station, 
The writer is indebted to Prof. A. Vincent Osmun, head of the department of botany of the Massachu¬ 
setts Agricultural Experiment Station, for criticism of the manuscript. 
Journal of Agricultural Research, 
Washington, D. C. 
ya 
(369) 
Vol. XXI, No. s 
June 1, 1921 
Key No. Mass.-6 
