Dec. 3, 1917 
Podblight of Lima Bean 
489 
PERPETUATION OF THE FUNGUS 
The finding of mature asci of this fungus on June 2, 1915, and on June 
11, 1916, and later on the dead vines and pods wintered out at Washing¬ 
ton, D. C., and on similar material under field conditions at Vineland, N. J., 
at about the same season of the year shows one way the fungus may live 
through the winter. This method of perpetuation is, however, not the 
only one. At intervals from October until June pycnospores were fre¬ 
quently found, and the fungus was isolated at will from field material. 
It is interesting to note in this connection that the pycnospores were 
produced periodically during the winter season, depending upon weather 
conditions. Following a period of a few days of relatively warm, rainy 
weather, they could nearly always be found in more or less abundance. 
For example, pycnospores were found on material examined on October 
24, January 2, 14, and 21, February 7, March 6, April 14, and June 2. 
Isolations were made on October 24, January 2, February 7, May 31, and 
June 2. Similar results were obtained with Phomopsis vexans (Sacc. and 
Syd.) Harter, the pycnospores of which were found in May and June on 
wintered-out material. However, the same material examined in Decem¬ 
ber, January, February, and April bore no pycnospores but the stylospores 
appeared to be more numerous during the spring months. The'appear¬ 
ance of pycnospores was roughly coordinated with rainfall and tempera¬ 
ture, since on May 22, following a period of rainy weather and relatively 
high temperatures, they were found in great abundance. 
It is likely also that the organism may live for a considerable time in 
the seed. The writer has isolated it in pure culture from the interior of 
both seeds and pods after surface disinfection in mercuric chlorid. From 
these results it is apparent that the fungus invades all parts and it is not 
unlikely that it is carried fron one season to the next on the seed. That 
the fungus is not readily killed by drying' is evident from the fact that it 
was isolated from dried specimens kept in the laboratory for nine months. 
It would probably survive such conditions even longer. These results 
are supported by the earlier work of Halstead (17), who in 1901 called 
attention to the fact that the seeds were invaded by the fungus and sug¬ 
gested the possibility that it was carried through the season by that 
means. 
MODE OF INFECTION 
It is not always easy to explain how a parasite gains entrance into its 
host. It is safe to conclude that, if a fungus is parasitic, it may enter 
through wounds, it being merely necessary to show that the host is 
subject to wounding under natural conditions. Other types of penetra¬ 
tion as, for example, through the unbroken epidermis or by way of the 
stomata are not always easy to demonstrate. There is no doubt that 
physical factors such as rainfall, temperature, humidity, and stomatal 
movement all play an important r 61 e in the penetration of the epidermis 
