5 oo 
Journal of Agricultural Research 
Vol. XI, No. io 
30 per cent after a two-minute exposure in a i-to-250 solution, and 
only 75 per cent in a i-to-ioo solution after one minute. Clark (j) 
found that 1 part by weight in 273,066 parts of water permitted the 
germination of but 10 per cent of the spores of Oedocephalum albidum 
after 11 hours' exposure, as compared with 95 per cent after four hours 
in the controls, and greatly injured the mycelial development. 
As regards the results, it should be stated that in all cases where the 
spores were not killed the germination was very much retarded. The 
colonies in the controls became visible to the naked eye in about 48 
hours. A long exposure in a weak solution retarded germination to 
about the same degree that a short exposure in a correspondingly more 
concentrated solution. That the germination of Lima bean seeds is not 
injured by exposure for 10 minutes in the strongest solutions of mercuric 
chlorid, formaldehyde, and copper sulphate to which the spores were 
subjected is shown by a series of experiments discussed under “Control 
measures." 
CONTROL MEASURES 
Halsted (17) was the first, and probably the only one, who has ever 
done any experimental work on the control of the podblight of Lima 
beans. In these experiments spraying the dwarf Limas with Bordeaux 
mixture or soda-Bordeaux mixture yielded very favorable results. 
Although he evidently did not spray the pole Limas, he suggests that the 
disease could be checked by so doing. It is now known that the fungus 
attacks the leaves before the pods are set, and it is likely the pods become 
infected from them. In view of this fact, the first spraying should be done 
when the plants are 1 or 2 feet high, and should be repeated often enough 
to keep the foliage covered. 
From badly infected pods the fungus invades the seed, where it may 
live for a considerable time. Infected seed are usually dark, shriveled, 
and immature. They probably would not grow, and, if they did, would 
give weak, sickly plants. Only plump, bright seed should be planted. 
Sound seed may be disinfected to kill the adhering spores by submerging 
for 5 or 10 minutes in a solution of mercuric chlorid (1:1,000), formalde¬ 
hyde (1:100), or copper sulphate (1:100), after which they should be 
rinsed in water. 
A series of experiments has shown that germination was not injured by 
such a treatment. Healthy Lima bean seeds were sorted out; a part 
were treated for 5 minutes and a part for 10 minutes. After rinsing in 
sterile water, they were laid between moistened filter paper and ger¬ 
minated. The results showed that seeds exposed for 10 minutes gave 
just as good germination as those soaked in sterile water for the same 
length of time. It should be mentioned in this connection that those 
soaked in sterile water were all more or less covered with saprophytic 
molds, while those treated with mercuric chlorid, formaldehyde, and 
copper sulphate were comparatively free. 
