April, 1906.] Ascochyta pisi — Disease of Seed Peas. 
509 
A. pisi Lib., is described as being either 1-septate or 1-celled. 
A. Bolthauseri Sacc.,® found on the leaves of bean, is often 
2-septate. 
Cultures. — Halsted'^ who was first (so far as the writer is able 
to learn) to note and to figure the pea seed affected with Ascochyta 
pisi, states that seed “apparently healthy when placed in the 
ground, soon show patches and spots of a dark color, which are 
also the spore bearing places of Ascochyta.’’ 
Krueger’ noticed the presence of the fungus by soaking seed 
for twenty-four hours in water, when dirty spots would appear. 
When left for forty-eight to seventy-two hours, the mycelium 
grew out into the water forming a white mass of radiating threads 
similar to those of Saprolegnia. All these results of Halsted and 
Krueger were verified. 
If one places such diseased peas in a seed germinator for sev- 
eral days, a heavy coat of white mould will be formed about 
them. On removing these to a covered dish where less moisture is 
present, numerous reddish-brown pycnidia are formed all through 
and over this white fluffy mass of mycelium. (Of course this 
mycelium must not be confused with a similar growth of some 
such fungus as Fusarium which often contaminates peas and 
beans, when not kept dry, — especially just before harvesting.) 
Peas which failed to germinate in the ground, were removed, 
with the result, that they too, soo developed pycnidia on the 
mycelium surrounding them. The germination of such seeds 
is very poor. Krueger found the germination of very badly af- 
fected seed to be 20%.- In similar experiments conducted by 
the writer the germination was only 0%. Such peas seldom reach 
maturity when they do germinate, as the fungus affects the base 
of the young plant. Hiltner' records the sudden dying of peas 
from such attacks at the base of the stem. The fungus was 
carried over to the young plants by the seed, a fact determined 
through experiments by Jarinsb The result of these early at- 
tacks by the fungus, is all sizes and vigor of plants. Plants of 
equal age, range in height from two inches to four feet. In the 
struggle between the fungus and host, the latter may not notice- 
ably increase in size for a long period, or it may succumb at anv 
time. Young plants six inches high, affected with the fungus, 
were planted against healthy ones of the same size, with the re- 
sult, that the latter became diseased in a few days. Later, fruit 
bodies formed abundantly. 
5 . Bulthauser-Amrisweil. Blattflecken der Bohne. Zeit. f. Pflanzenkr., p. 1.35. 
0. Halsted. Some Fungous Diseases of the Pea. N. J. Rept., pp. 357-362. 1893. 
7. Krueger, Ungewoenliches Auftreten von Ascochyta pisi Lib. on Erbsenpflanzen. 
Centl. f. Bak. u. Par. 2. I., p, 620. 1895. 
8. Hiltner, Erbsenmuedigkeit. Sachs, landw. Zeitung.. 1894, No. 18. 
9. Jarins, Ascochyta jiisi bei parasitischer und saprophyter Emahrung. Bibl. Bot., 
Heft 34, 1896, c. tab. 
