Bulletin 151, Truck and Garden Insects


hydrated lime or the milk obtained from slacking 2 pounds of
quick lime in water. If jassids are also present, add tobacco
to the solution.
 BEAN-WEEVIL (Bruchus obtectus)
 There are two or three species of weevils that infest beans.
The most common is Bruchus obtectus (fig. 59). The others
are more common on cowpeas and will be treated under that
heading. The ravages of this insect on dried beans are very
conspicuous; in fact, if not checked, it will entirely destroy
seed beans. They also damage snap beans. The infested pods
show wart-like swellings where the female punctures them to
lay eggs in the cavity of the pod. She gnaws out a narrow slit
and then inserts her ovipositor in the hole and lays the egg.
 These speckled" pods should not be
 confused with those having spots
 caused by the fungus, Colletotrichum.
 Those spots caused by the fungus are
 sunken instead of elevated and attain
 a much larger size. The egg hatches
 6 W in from 1 to 3 weeks, according to the
FIG. 59.B e Bea wee v 11 prevailing temperature, into a small,
 (Br u c h u s obtectus): a, worm-like larva. This requires from
 Adult beetle, much en
 large; b, infested bean. 11 days to 6 weeks to become full
 (From U. S. Bur. of Ent.)
 grown and then changes into the pupa.
From 5 to 18 days later the adult emerges. This is an ashy-
black beetle about a tenth'of an inch long with hard wing-cases
and' somewhat flattened body.
 Nothing can be done to protect the beans in the field from
the ravages of this insect. The best method of control is to
plant clean seed in a field that has not recently produced a crop
of cowpeas or beans. Breeding in dried beans can be prevented
by keeping the beans in cold storage (32 to 34 degrees F.) for
two months or more, or they may be fumigated as recommended
for stored seeds.
 LESSER CORN STALK-BORER (Elasmopalpus lignosellus Zell.)
 This insect is injurious to corn in the states farther north;
in Florida it does more damage to cowpeas and beans, altho it
is injurious to corn. Next to the bean-jassid it is the most injuri-
ous insect on fall-planted beans. It often destroys almost the
entire stand if control measures are not adopted. The insect
.is a bluish-green caterpillar (fig. 60, d) which bores into the