GARDEN BEANS CULTIVATED AS ESCULENTS. 87 
use should not be allowed to fully ripen but is better if 
gathered when the hilum first turns black. For ripe 
seed the crop may remain longer in the field. 
The most destructive insect enemy is the bean-weevil 
(Bruchus obsoletus Say), a brownish-black beetle about 
one-tenth inch long. The eggs are laid on the young pods 
at the time when the seed is beginning to form, the larvae 
hatching eight or ten days later and immediately working 
their way into the seed, feeding on the latter most of the 
summer. Many larvae usually burrow into the same seed, 
which destroys its germinating power and renders it worth- 
less for food. As a rule the larvae pupate in early autumn 
and some transform to beetles in a few weeks while others 
remain in the pupa stage until spring. The partially 
grown larvae may be killed by subjecting the fresh ripe 
seed to a temperature of 145° Fahrenheit. The larvae or 
beetles may be destroyed by fumes of bisulphid of carbon, 
benzine or gasoline, by placing the seed in a tight vessel 
and adding a little of either substance. Care should be 
taken that no fire comes in contact with the gases. 
In the forcing house, beans are subject to attack from 
red spider and green fly. The former may be kept in 
check by frequent syringing and the latter by fumigating 
with tobacco. 
Numerous fungous diseases are known to occur on this 
group of plants, but only a few cause serious injury. They 
may be held in check by spraying with a weak solution 
of Bordeaux mixture, or ammoniacal copper carbonate. 
The bean anthracnose (Colletotrichum lagenarium Pass.) 
is probably the most destructive. It develops most freely 
during rainy weather, producing ulcers on the young 
pods and leaves and frequently extending to the stem and 
branches. When occurring on the pods it is known as 
pod spot. The beginning of the disease is but a minute 
speck which soon enlarges and in extreme cases covers the 
entire pod or leaf. 
