894 
Journal of Agricultural Research 
Vol. V, No. 19 
the disease was evidenced by only one or two spots on each leaf. Two 
of these plants were found in plot 1, one in plot 2, and two in plot 4. It 
will be noted that on this date plot 1 of field 10 had a maximum of 79 
affected leaves on a single plant, plot 2 had 30, plot 3 had 94, and plot 4 
had 45. A final count of the number of diseased leaves in field n was 
made on September 1, with the result that 12 per cent of the leaves in 
plot 1 were affected, 11 per cent in plot 2, 15 per cent in plot 3, and 14 
per cent in plot 4. It should be said in explanation that none of these 
plants had more than six affected leaves, and most of them had only one 
or two, upon which there were at most only a few spots. Ten days 
prior to this a final count on field 10 showed a minimum of 23 diseased 
leaves per plant and a maximum of 297. This number would, no doubt, 
have been considerably greater by September 1. 
The most significant conclusion that one is forced to make from these 
tests is that seed treatment, either by itself or in conjunction with 
rotation, does not eliminate peanut leafspot. This conclusion is further 
supported by the results obtained from the rotation tests given in Table I. 
The peas used in planting fields 1, 2, 5, 6, and 7 were shelled prior to 
planting, thus eliminating the danger of introducing infective material 
at the time of planting. In these fields, 100, 54, 26, 100, and 13.5 per 
cent, respectively, of the plants were affected with leafspot. The peas 
used in planting fields 3 and 4 were not shelled, and 41 and 95 per cent, 
respectively, of the plants were diseased. As can readily be seen from 
these figures, the removal of the shells prior to planting contributed 
nothing toward keeping the crop free from disease. 
DAMAGE SUSTAINED BY PEANUT PLANTS AS A RESULT OF LEAFSPOT 
In order to measure the degree to which leafspot affects the foliage of 
peanuts, an effort was made to determine the relation between the total leaf 
area and the diseased area of a peanut plant. The plant used was taken 
from field 10 and may be regarded as a plant having an average proportion 
of diseased tissues. The method employed consisted in weighing pieces 
of paper corresponding in area to the total and the diseased leaf surface. 
From paper of good quality, pieces, each equal in area to one of the leaves 
of the plant, were cut. After these had been weighed, areas correspond¬ 
ing to the diseased parts of the leaves were outlined, and these areas 
were then removed. The paper leaf areas with the excised diseased areas 
were again weighed with the following computed results: The total 
weight of the leaves on a single plant is found to be 64.07 gm. Of this 
weight, 20.10 gm. are wholly free from spots; 12.39 & m - are dead as a 
result of the attacks of Cercospora personata and have for the most part 
fallen off; the remainder, 31.58 gm., are regarded as diseased leaves. Of 
these diseased leaves 10.18 gm., or 32.04 per cent, are occupied by the 
fungus. When 12.39 an d 10.12 gm. are combined, it is found that 
35.07 per cent of the entire leaf area is lost to photosynthetic activity. It 
