842 
Journal o f Agricultural Research 
Vol. XXXI, No 9 
The disease on cowpeas was first found at Vallonia, Ind., in August, 
1919 ; and was next found at Decker, in southern Indiana, in August, 
1920. In August, 1921, it occurred in an experimental plot of Whip¬ 
poorwill cowpeas at La Fayette, Ind., and has occurred in the writers’ 
plots in 1922, 1923, and 1924. The disease appears to be very 
widespread, since it has been found in seed from South Carolina, 
Virginia, and Washington, D. C., and was noted in the field in 1922 
near Decker, Ind., Seaford, Del., tod Louisville, Ky. Seiyo Ito, who 
examined the writers’ plots at La Fayette, said that the same disease 
also occurs in Japan. 
In 1923 the disease was found in Knox County, Ind., and in Kansas 
by R. P. White, and in Florida by W. B. Tisdale, who also reported 
it as a serious trouble in 1924. In 1924 the disease was serious in 
the field crop (variety, New Era) in Jackson County, Ind., and was 
more severe in the writers’ plots at La Fayette than in the preceding 
three years. This disease as it occurs on lima beans was noted 
commonly in gardens in Indiana in 1919 and 1920, and it occurred 
to a considerable extent in 1923 and 1924. 
HOSTS 
Greenhouse inoculations and field studies have shown that the fol¬ 
lowing are hosts of this parasite: Cowpea {Vigna sinensis [L.] Endl.); 
catjang ( Vigna catjangrf alp.); hyacinth bean ( Dolichos labldb L.); 
Florida velvet bean {Stizolobium deeringianum Bort); adsuki bean 
(.Phaseolus angularis Wight); lima bean ( Phaseolus limensis Macf.), as 
represented by the Large White Pole, Giant Podded Pole, and King 
of the Garden varieties; bush lima bean {Phaseolus limensis Macf. var. 
limenanus Bailey), as represented by the Burpee’s Bush and Ford- 
hook varieties; and the dwarf sieva bean {Phaseolus lunatus L. var. 
lunonanus Bailey), as represented by the Henderson’s Bush variety. 
Tisdale and Williamson {2Jf) had found the varieties Burpee’s 
Bush, Fordhook, King of the Garden, Dreer’s Bush, and Hender¬ 
sons Bush to be susceptible. Natural infection with what is in all 
probability the same organism was found rather abundantly on the 
eaves of the common native weed, tick trefoil {Desmodium canescens 
L.] DC.), in a fallow field near La Fayette, Ind., on August 23, 1924, 
and has also been found on asparagus bean {Vigna sesquipedalis 
Wight) in field plots. 
All of the following 23 varieties of cowpeas tested have proved to 
* be susceptible: Whippoorwill, Brabham, Early Red, Early Black, 
Early Buff, Taylor, Black, Red Ripper, Iron, Conch, Groit, New 
Era, Clay, Wonderful, California Blackeye, Early Ramshorn Black- 
eye, Cream Chowder, Gallavant, Large Blackeye, Arlington, Columbia, 
Progressive White, and Victor. 
SYMPTOMS 
On the cowpea leaves, the spots as usually seen in the field are 
irregularly circular or lobed rather than angular, and are 1 to 4 mm. 
broad, sometimes larger. Very young spots are small, circular, 
sunken dots, first water soaked or greasy, later claret-brown in color 
{16) (pi. 1, A). The larger lesions are characterized by a buff center 
surrounded by a conspicuous maroon or claret-brown margin about 
1 mm. in width (pi. 1, B; pi. 2, A). Leaf lesions frequently become 
