992 Farmers’ Bulletin 1275. 
be supplied by southern-grown beans and peas. Practically all the 
dried beans grown for seed and for food are grown in these northern 
States where the bean weevils are not able, because of climatic checks, 
to cause so much damage. Of course weevils do not affect the grow- 
ing beans to be eaten green, as “ string beans” or green shelled beans, 
'for such beans are not, at the time of gathering, infested; or if in- 
| fested, the grubs are too small to 
interfere with their value as 
food. 
GERMINATION AFFECTED 
BY WEEVIL ATTACK. 
The germination of beans, 
peas, and cowpeas is likely to be 
seriously affected by the devel- 
opment of weevil larve. If the 
embryo is destroyed by the larva, 
or if too much of the bean sub- 
stance is eaten, the seeds can not 
grow. 
Beans as badly infested as_ 
those shown in Figures 1, 7, and 
23 are worthless for planting. 
As the young bean or pea plant 
depends upon the food stored in 
the seed to give it its first start, 
the destruction of any portion 
of the seed by weevils lessens by 
so much the vigor of the plant. 
In one experiment on record, 
only 50 per cent of infested beans 
germinated, and of these 30 per 
and 
seeds) 
The skin 
Fig 22.—Beans (six upper 
chick-peas (two lower seeds). 
of the beans has been removed to reveal 
the cavities eaten out by the common 
bean weevil grubs. The grubs have been 
killed by fumigation and have turned 
black. Note the white paper-like cell or 
cocoon about each of the grubs. The 
chick-peas have been cut open to show 
how the larve of the four-spotted bean 
weevil can burrow to the very center of 
the seed. Slightly enlarged. 
cent were so badly injured that 
they could not develop into nor- 
mal plants. The smaller the 
seed, the greater proportional 
damage a single weevil grub can 
cause. One grub ruins a small 
cowpea seed (see Fig. 14) or a 
lentil (see Fig. 18), whereas it 
would not so seriously affect a large seed like the lima bean. The 
germination of broad beans infested with 1, 2, 3, and 4 or 5 broad- 
bean weevils was found to be reduced from a normal of 95.7 to 82.7, 
72.7, 71.1, and 69.6 for new crop seed. In examining 50 garden peas 
infested by the pea weevil 33 were found with the embryo wholly or 
partially destroyed and in another case only 69 out of 275 infested 
peas had undamaged embryos or germs. 
