1898] ON SOME ASPECTS OF VEGETABLE PATHOLOGY 193 
additional point might be mentioned. On a very badly diseased 
plantation it was noticeable that the spread of the mildew prac- 
tically ceased about September 10, although the vines continued 
to flower and produce pods until October. I am at a loss to 
account for this sudden cessation of fungous activity, but it is 
worthy of notice in this connection that after the date above 
mentioned hardly any bees were seen in the plantation. 
It seems almost certain then, that in the case of this 
mildew at least, insects are the principal agents in the dissem- 
ination of the fungus. 
But I have already stated that the fungus sometimes appears 
‘sewhere than upon the young pods. In some cases it is 
spient from the respective positions of old and fresh points 
of infection upon the leaves or mature pods that the spores have 
_ carried by the rain or dripping dew from one portion of 
the vine to a subjacent one, but certain facts led me to think 
=e wind played a considerable part in the infection of 
ing . - In order to test this matter I pursued the follow- 
i. . The mildew is usually confined to comparatively low, 
ee, ea The grounds of the Connecticut Experiment 
os ead an elevated position, the land is well drained, 
thig a. and sandy, and so far as I know, lima beans on 
Occupied ¢ ave never mildewed. During the past summer they 
Wo rows running east and west. Directly south of 
a 2 distance of about 100 feet, were two rows of bush 
the mj Pig north and south (fig. 5). On August 14, when 
*w had been abundant for a month or more on a 
at a distance f ab wy ose : ones ie 
ion, the Stati - he out a mile in a straight ine from 
be perfect] , ation ues were carefully examined and found to 
. from mildew. The following day two mildewed 
Mildeweg a from the farm above mentioned, and the 
thy ang aa of one of them was rubbed upon a single 
of Dole ee Bo mature pod at the east end of each row 
*€n succeeg: cag prevailing winds at the time and for the 
. oe ay S varied from northwest to northeast. Within 
mildew appeared abundantly upon the two infected 
Week the 
and ; : 
from this point swept down both rows from east to 
