16 Farmers’ Bulletin 1275. 
found in cowpeas in any commercial center. Although it prefers 
cowpeas (see Fig. 14) and is, with the four-spotted bean weevil, 
the worst pest that the cowpea has, it may attack the common pea, 
pigeon pea, lentil, chick-pea, mung bean, and common white bean. 
The adult weevil is about an eighth of an inch long and may be 
distinguished from weevils discussed in this bulletin by the elevated 
ivory-like spots near the middle of the body, as shown in Figure 13. 
Like the bean weevil, the cowpea weevil usually begins to infest 
cowpeas while they are developing in the field by laying its eggs 
upon the pods. It also 
is able to breed genera- 
tion after generation in 
stored cowpeas and of- 
ten reduces them to a 
powder. Because of 
the very warm weather 
of the Southern States, 
where the cowpea 
weevil is most severe in 
its attack upon cow- 
peas, the grubs mature 
very fast and often the 
adults may emerge as 
soon as the crop is ripe. 
In a fairly warm or in- 
door temperature six to 
Fie. 15.—A cowpea seed showing eggs of a cowpea 
weevil. The eggs of bean and pea weevils vary in 
shape but are always small, ranging in length 
from one-fiftieth to one twenty-fifth of an inch. 
They are white or whitish, and may be laid any- 
where upon the outside of the seed, as indicated 
here, or in cavities in the seed made by a_ pre- 
vious generation of grubs, or on sides of containers 
such as burlap sacks, barrels, etc. The eggs can be 
distinctly seen on seeds, as tiny white specks. Much 
enlarged. 
eight generations may 
mature annually in a 
climate like that of 
Washington, D. C. 
The beetles may live 
as long as 36 days, al- 
though the average life is probably about 12 days. At an average 
temperature of about 70° F. eggs may hatch in 8 days, larvee become 
full grown in 17 days, and the pupa stage passed in 7 days; thus giv- 
ing 32 days as the time required for the development of one gener- 
ation from egg to adult. During very hot weather a generation 
may mature in as few as 18 days (egg, 3 days; larva, 12 days; pupa, 
3 days) to 21 days (egg, 4 days; larva, 13 days; pupa stage, 4 days). 
During cooler weather 45 days (egg, 10 days; larva, 25 days; pupa, 
10 days) and 60 days (egg, 10 days; larva, 40 days; pupa, 10 days) 
were required. Of course this period may be extended to cover 
three or four months during winter weather." 
11 Chittenden, F. H. 
1912. 
The Cowpea Weevil, U. S. Dept. gr., Bur. Ent. Bul. 96, Pt. VI, 
