54 
House & Garden 
THE CONTROL of PLANT INSECTS and DISEASES 
Preventive and Remedial Measures Which May Be Relied Upon to Aid in 
the War on Garden Pests and to Help Maintain the If Arid’s lood Supply 
T HE yearly tribute which we in America 
pay to insects and diseases that attack our 
crops is on a Liberty Loan scale. Some idea 
of its tremendous extent may be had from a 
brief survey of the figures compiled by the 
Government. It is estimated that the damage 
to wheat alone in the United States is over 
■$100,000,000. In corn the loss is conceded to 
be over $40,000,000. Other cereals would 
bring the total up to $300,000,000. Forage 
crops are destroyed or injured to the extent of 
$75,000,000. Cotton suffers a loss of $25,- 
000,000; tobacco, $10,000,000, while truck 
crops pay a penalty of some $65,000,000. The 
loss to fruits is placed at more than $40,000,- 
000. These estimates do not take into con¬ 
sideration the tremendous losses to forests and 
to the small home gardens which are not listed 
in statistics of this kind. 
Plants, like other growing things, are sub¬ 
ject to various diseases. In many cases these 
are due to unfavorable conditions of growth, 
some beyond our control, but more generally 
the result of not understanding the needs and 
requirements of plants or ignoring them if we 
do understand. Most plant diseases and a 
great many of the insects are the result of a 
S CALES of all kinds must be smothered. They 
have special organs on their bodies which en¬ 
able them to drain the sap from plants they 
attack and quickly destroy. A few years ago the 
San Jose scale was viewed with considerable alarm, 
but it is not thought of seriously today because the 
process of eliminating it is simple. 
The individual San Jose scale is nearly circular and 
no larger than an ordinary pinhead. Should it be 
allowed to become really abundant it will form a sort 
of crust on the branches and cause minute reddish 
spots on the fruit. Ordinarily three or four broods 
are produced in a season. The young scales are 
born alive, several hundred to each mother. Breed¬ 
ing normally continues until late in the autumn, when 
all ages of the scale are killed by the cold weather 
except the half-grown, tiny black ones whose duty it 
is, in the unhampered scheme of Nature, to hibernate 
and carry on their species with the return of warm 
weather. It is these wintering-over scales that spray¬ 
ing is designed to destroy. 
Oyster-shell scale is well named because of its ap¬ 
pearance. The individuals are about %" long and 
shaped somewhat like an oyster shell. The eggs live 
through the winter under the protection of the old 
WILLIAM C. McCOLLOM 
Painting the trunks and brunches with white¬ 
wash is a preventive of oyster shell scale 
TREE and SHRUB SCARES 
Destroyed by Smothering 
Spraying with arsenate of lead just as the 
blossoms fall helps to control curculio 
weak, sickly growth caused by unfavorable 
growing conditions under which insects and 
diseases flourish. There are as many fatal 
diseases of plants as of the human race; but 
the greatest contributing factor is unhealthy 
growing conditions. Plants that have plenty 
of food in the soil, that are kept well cultivated 
so that the roots can breathe, and well supplied 
with moisture (natural methods preferred), are 
usually robust and if brought in contact with 
diseases will have vigor enough to ward 
them off. 
To fight insects we should know something 
of their life histories, of their habits, of what 
conditions are favorable for their propagation; 
when they are most vulnerable to attack. All 
efforts in our elimination of plant pests would 
be in vain were it not for the help we receive 
from the natural enemies of the insects we are 
fighting. Prominent among these are many 
species of native birds. 
With this general introduction we are ready 
to take up in detail the study of insects and 
diseases, together with measures which must 
be taken against them if our gardens are to be 
of maximum aid in the nation’s fight for pro¬ 
duction. 
scales, and in average seasons hatch late in May. 
Close examination of the bark about this time may re¬ 
veal the young scale, looking like tiny white lice, mov¬ 
ing about on it. Where trees are regularly sprayed for 
San Jose, the oyster-shell also is usually controlled. 
Trees infested with scale should be sprayed at least 
twice while dormant. If this is done thoroughly in 
autumn after the leaves fall and again in spring be¬ 
fore they bud, very few scales will survive. When 
spraying use plenty of force so that the spray is 
forced into all crevices and openings in the bark. 
Lime sulphur and salt spray is unquestionably a good 
one, but involves a very unpleasant process, and 
there are any number of miscible oil sprays that are 
specifics for this trouble and will be found satis¬ 
factory. If it rains within forty-eight hours after 
applying the spray, the work should be done over 
again, as it takes two days to smother the scale. 
Painting the trunks and large branches of fruit 
trees with lime is a worth-while practice. It will 
not kill scale, but will destroy other insects or pups 
gathered on the bark. It also has a tendency to pre¬ 
vent scale from attacking. Poor, sickly growing trees 
are invariably the first to be attacked, and should be 
examined frequently. 
Name 
Identification 
Effect on Plants 
Causes 
Plants Attacked 
Prcventatives 
Cure, if Any 
SAN JOSE SCALE.. 
Close examination of 
infested bark will 
show that it is cov¬ 
ered with a soft, 
brownish - black 
scum. 
This scale will de¬ 
stroy the tree if not 
checked. It drains 
the sap through the 
bark. 
The scale is carried 
about by birds, 
Breeds very rapid¬ 
ly, one specimen 
producing about 50,- 
000,000 a season. 
All hard wooded 
trees, but fruit trees 
are particularly sus¬ 
ceptible. 
There are several spe¬ 
cifics with which 
trees should be 
sprayed once a year 
when dormant. 
Spray fall and spring 
with lime sulphur 
and salt mixture or 
any of the miscible 
oils. 
OYSTER SHELL 
SCALE . 
(Juite large and ap¬ 
pears as black and 
white blotches on 
the bark, especially 
of young wood. 
If neglected this scalr 
will prove as fatal 
as the San Jose, 
though not in so 
short a time. 
('arried about by 
birds and trans¬ 
ferred on new nurs¬ 
ery stock. 
Practically all trees, 
but smooth bark 
sorts like willow, 
poplar, peach, etc., 
are the favorites. 
Mild spraying once a 
year. Painting the 
trunks and branches 
with whitewash is 
also good. 
Spray spring and fall, 
the same as for 
San Jose scale. 
SOFT SCALE. 
Soft bodied, close 
clinging scale that 
covers the wood of 
hard wooded trees 
and shrubs. 
The sap is sucked by 
means of the spe¬ 
cial organs on the 
sides of the body. 
Transported by birds. 
Increases very rap¬ 
idly. 
The new wood of all 
hard wooded trees 
is subject to at¬ 
tack. 
Spraying with strong 
tobacco or kerosene 
emulsion when in 
leaf. 
Spraying the trees 
spring and fall with 
any of the sprays 
recommended for 
other scale. 
