848 
Journal of Agricultural Research 
Vol. XXXI, No 9 
point (pi. 6, A, B, and C). Sometimes the entire distal portion of the 
pod fails to enlarge. Large lesions frequently penetrate through the 
ovary wall to the seed, causing a stunting, shriveling, and dark dis¬ 
coloration of the latter (pi. 3, C and E). However, attempts to 
separate upon this basis the infected from the healthy in commer¬ 
cial seed, have been unsuccessful. Tisdale and Williamson (2Jf) found 
similar pod lesions and resultant seed infection in the lima bean. 
In cowpea seedlings from infected seed the cotyledons bear large 
lesions which frequently cause a water-soaking or dark discoloration 
and a shriveling or constriction of a considerable portion of the 
cotyledon (pi. 3, D). Such lesions are frequently accompanied by a 
transverse crack or fissure, and may kill the cotyledon prematurely. 
Oval, maroon lesions also occur on the hypocotyls and epicotyls 
of such seedlings (pi. 3, F and G). 
From the infected cotyledons or from epicotyl lesions, infection 
of the vascular bundles occurs (pi. 4,F), and the invasion frequently 
extends up along one or more bundles through the petiole and out 
into the veins of the first leaf. This type of infection is visible as 
an internal reddish-brown streak within the vascular bundles, and 
causes a yellowing or wilting and blighting of all or portions of one 
or both of the first leaves. The affected portions of such leaves may 
show a darkened network of veins (pi. 2, C), and such infection has 
been observed to cause a rather extensive, shiny, brownish discolor¬ 
ation of the lower surface of the leaf along the veins. In some cases 
a preliminary yellowing of the veinlets and a stunting of the cor¬ 
responding half of each leaf was observed. In extreme cases the 
entire seedling may be stunted or may wilt and die. Similar wilting 
and blighting effects have been noted on the first compound leaves 
of fieldgrown seedlings (pi. 5, A), and also on older plants as a con¬ 
sequence of early infection qf the petiole which had resulted in exten¬ 
sive internal invasion of the vascular tissues. Under such condi¬ 
tions, irregular bleached areas of considerable extent frequently 
occurred on the leaf blades (pi. 2, C), accompanied sometimes by 
an extensive reddish discoloration of the lower epidermis. 
The tendency to invade the veins has been noticed in the case of 
lesions on or near the veins of young leaves, in which case a brown 
streak may be traced out through or along the vein and into its 
smaller branches (pi. 1, A, B; pi. 2, D). Such infection may cause 
a yellowing or wilting of portions of the lamina supplied by the 
infected vein. Thus, although this is typically a spot disease, there 
are distinct evidences of localized vascular infection, particularly 
in the seedlings, which results in symptoms of a systemic nature. 
In the Early Buff variety of cowpea this disease should not be 
confused with another spot disease with which a species of Clado- 
sporium is associated. The latter trouble is characterized by smaller 
2 1e to black spots on the pods, irregular in outline, and by oval, 
en, purplish spots on the young stems and peduncles. These 
lesions may have a tan center on which appears a greenish, velvety, 
fungous growth. Pod infection occurs very early and often causes 
great distortion of the pods. 
Early stages of the leaf spot caused by Amerosporium oeconomi - 
cum E. and T., as observed on the New Era variety, somewhat 
resemble bacterial spot, but the white center, concentric rings, and 
pycnidia of older lesions serve as distinguishing characters. The 
