The More Important Apple Insects. | 63 
as a summer spray, which, observations and experiments have shown, is effec- 
tive in destroying many of the newly hatched insects, so that the trees 
are kept fairly well freed of the pest as an incident to the use of the wash for 
other purposes. The effectiveness of 
parasitic and predatory insect enemies 
in reducing the scale has also appar- 
ently been gradually increasing. In 
fact, the scale in certain orchards has 
become so reduced in numbers that it 
has been found feasible occasionally to 
omit the dormant treatment without 
undue increase of the insect. Such 
omission, however, if made, should be 
based on. very careful examination of 
the orchard to ascertain whether such 
ee ee Uae zt Tic. 126.—Apples spotted by San Jose 
able seasonal conditions the scale is saniles 
uble to increase rapidly and may do 
serious damage to the twigs and in spotting the fruit, although present on 
the trees during the dorimant period in apparently negligible numbers. 
In common with other seale pests, the San Jose scale is a sucking insect, 
and lives upon plant juices which it extracts from the twigs, limbs, trunk, 
foliage, and fruit. Small reddish discolorations will frequently be found 
at the point of feeding, and on the fruit itself these dots are conspicuous, 
unsightly, and lower its market 
value (fig. 126). When abundant 
this insect is capable of killing 
young trees within a few years, 
and older trees may ultimately be 
destroyed, although the process is 
a slower one (fig. 127). Infested 
trees are dwarfed and unthrifty 
in appearance, and the incrusted 
twigs have an ash gray color (fig. 
128). Some years aco it was not 
uncommon to find entire orchards 
destroyed, but in recent yeurs the 
trees have been well protected 
from itS ravages by means of 
spray solutions. It should not be 
inferred, however, thst the San 
Jose scale is no longer a dangerous 
pest, since in the absence of ade- 
quate treatment it could readily 
reestablish itself in numbers that 
would again result in enormous 
Iie, 127.—Apple tree practically killed by San losses to the fruit industry. It 
Fane scale. has been estimated that from the 
progeny of a single female there 
may result over 14 billion females in the course of one season. From this the 
fruit grower will appreciate how readily this insect can reinfest and destroy an 
orchard. The apple, pear, and peach are its favorite food plants. Other de- 
ciduous fruit trees are subject to attack, as are also many bush fruits, shade and 
forest trees, and shrubs. 
