THE BEAN LADYBIRD. 
19 
chiefly on the upper surface, cutting irregular holes in and through 
the leaves, while the larvae feed on the lower surface and skeletonize 
the leaves, seldom cutting through them. 
The adult is a robust beetle, about one-fourth inch in length, of 
oval outline, pale brown, with each wing-cover marked with eight 
small black spots. The larva is light yellow and armed with 
branched spines. 
The yellow eggs are deposited from about the middle of June 
until August on the lower surface of the, leaves, in clusters of -±0 
or more, and sometimes to the number of 1,500 by a single female. 
The larvae feed at first in colonies, but with larger growth scatter 
and become more or less solitary. The life cycle may be passed in 
summer in from 22 to 
30 clays; the eggs 
hatch in from 1 to 9 
days ; the larval period 
is between 15 and 21 
days; and the pupal 
period varies from 3 
to 6 days. In colder 
weather, however, 
these periods are 
longer. Two genera- 
tions or " broods " are 
produced annually. 
Cold weather in late 
autumn has the effect 
of destroying the in- 
sects, and their eggs 
are also destroyed by 
three species of pre- 
dacious ladybirds. 
In the control of the bean ladybird preventive measures are the 
most efficient, consisting of hand picking and brushing from the 
plants, clean culture, and early and late planting. Arsenicals possess 
some killing properties, but in the main act as repellents. Spraying 
with arsenate of lead, 1 or 2 pounds (powder), and with arsenite of 
zinc, 1 to 1^ pounds (dry) , to 50 gallons of water, are the most prom- 
ising. Bordeaux mixture, 1 1 50 formula, should be used alone and 
in combination with these arsenicals. Additional tests must be made 
with these substances to ascertain the most effective and economical 
combination that may be applied to the bean plants without scorching 
or burning the leaves. 
For the treatment of large areas infested by the bean ladybird, & 
traction sprayer with nozzles arranged for side spraying of the type 
shown in figure 5 is useful. Owing to the danger of scorching bean 
foliage, it is desirable that an up-to-date sprayer should always be used. 
Fig. 5. — Traction sprayer with nozzle arrangement for 
side spraying, of type useful for spraying beans for 
the tean ladybird. 
