FURTHER STUDIES ON PEANUT LEAFSPOT 
By Frederick A. Woef, 
Plant Pathologist t Alabama Agricultural Experiment Station 
INTRODUCTION 1 
A report of investigations of certain fungous diseases of peanuts has 
previously 2 been made. Since the appearance of that report the investi¬ 
gations have been continued for the purpose of obtaining additional data 
on certain phases of the work. Opportunity had not been afforded 
prior to the present year to test under field conditions the efficacy of 
rotation and seed treatment in the control of leafspot, Cercospora per - 
sonata (B. and C.) Ellis. Definite experimental data upon the agencies 
concerned in the distribution of leafspot had not been secured; neither 
had an effort been made to definitely correlate the destructiveness of the 
disease with the presence of certain climatic conditions. It was the 
primary purpose of the present work to secure information upon these 
phases of the subject. The results of these studies are, therefore, 
recorded as additions to the information contained in the previous pub¬ 
lication 8 upon investigations which were begun four year ago under the 
Adams fund. 
ROTATION TESTS FOR LEAFSPOT CONTROL 
* 
Because of the fact that the leafspot organism was found to live 
on fallen leaves in the field from one season to the next, 4 it was recom¬ 
mended as a rational method of control that the same fields be not 
planted to peanuts in successive years. Observations on the effective¬ 
ness of rotation were made at several widely separated points in the 
State, with the representative results which are recorded in Table I. 
In many cases it has been difficult to get reliable information as to the 
crops previously grown upon the fields in which these studies were made, 
since the tenants knew nothing of the system of cropping employed prior 
to their tenure. In determining the percentage of plants affected, the 
1 The writer received valuable aid in the field tests from R. C. Lett, farm adviser for Tuscaloosa County, 
Ala., on whose farm the seed-treatment tests were conducted, and from S. A. Wingard, who carefully and 
arduously assisted in the field studies. Indebtedness is hereby acknowledged to both gentlemen for these 
several services. 
3 Wolf, F. A. Leafspot and some fruit rots of peanut. Ala. Agr. Exp. Sta. Bui. 180, p. 127-150, 5 pi. 
19x4* Bibliography, p. 148-149. 
3 Wolf, F. A. Op. cit. 
4 When these leaves [diseased leaves which had remained out of doors from November until Mayl were 
kept moist as when placed in moist chambers, conidia were abjointed. Additional evidence that the 
fungus remains viable is to be found in the fact that leaf spots developed during May, on young plants, 
in a field which had grown a badly diseased crop the previous season. (Wolf, F. A. Op. cit., p. 135.) 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
ce 
(891) 
Vol. V, No. is 
Feb. 7, 1916 
Ala.—1 
