8 Farmers’ Bulletin 1275. 
WHERE WEEVILS IN STORAGE COME FROM. 
At harvest time grubs developing from eggs laid on or in the 
pods in the field may have devoured very little of the seed contents, 
but if the seeds are stored in a warm place, or in a climate where the 
weather is sufficiently warm, they continue to feed and become well 
grown. When well grown they have eaten out of the seed contents a 
cavity somewhat larger 
than themselves and ex- 
tending outward to, but 
not pucturing, the skin 
of the bean. (Fig. 5.) 
The grub then changes 
or transforms into the 
pupa (Fig. 10, c; Fig. 
12, c) and later into the 
adult. This adult has 
a pair of sharp jaws 
which it uses like a pair 
of scissors to cut out a 
circular flap (see Fig. 
6) in the bean skin, 
thus making the small 
round hole which is, to 
most gardeners, the first 
evidence that insects 
are in their beans. 
Through these openings 
~ 1 - the adults crawl out and 
Fic. 5.—Beans in which the common bea weevil by their presence in 
grubs have become full grown and have eaten out = S 
from the interior of the bean to, but not puncturing, sealed jars and other 
the skin. Ags they transform to adult, each insect containers cause much 
darkens and this dark color shows through the thin 
skin and makes the dark, sometimes bluish, tran- concern. 
slucent spots in beans. Such spots indicate that 
seeds are infested. It should be remembered that DE Ss ER e O N 
while the grubs are still growing they are white, CONTINUES IN 
and seeds do not indicate their presence by any 
such dark spots as shown above. Considerably STORAGE. 
enlarged. 
With the exception of 
the pea weevil that attacks the different varieties of peas, the 
broad or Windsor bean weevil, and the lentil weevil, the weevils 
attacking beans and cowpeas continue to produce generation after 
generation in dried seeds in storage. (Fig. 7.) The pea and the 
broad-bean weevils will die in storage and can not reproduce unless 
they can find growing plants in which to lay eggs. But the ordi- 
nary bean and cowpea weevils lay eggs for successive generations 
as readily upon dried seeds in storage as upon the growing plants 
