SPRINGFIELD, N. J. 
107 
Some Facts About Controlling Insects on 
Ornamental Plants 
Because of the many different kinds of ornamental plants 
and the thousands of insects attacking these plants it is impos¬ 
sible to give control methods here for all these insects. There¬ 
fore, this brief article is presented on some of the fundamental 
principles of insect control. Difficult cases of insect control 
should be referred to us or to your State Entomologist for 
advice. 
IMPORTANCE OF FEEDING HABITS 
The method of controlling any specific insect is largely deter¬ 
mined by the manner it obtains its food. If it bites off, chews 
and swallows solid particles of the foliage, bloom or fruit it can 
often be best controlled by stomach poisons, such as arsenate of 
lead, fluorine compounds, etc. ; if it obtains its food by inserting 
its mouth parts through the surface and sucking out the plant 
juice, one must use contact poisons, such as nicotine, rotenone, 
pyrethrum, etc. The above two methods are effective where the 
insects feed upon exposed surfaces. If they bore inside the leaves, 
fruit, stems, trunk or roots, other methods are often necessary. 
Thus, how the insects feed and their habits have an important 
place in how to control them. 
STOMACH POISONS 
The most common stomach poison for use on ornamental 
plants is arsenate of lead. It may be obtained in a white pow¬ 
dery material, or in a paste form. The powder is usually used at 
the rate of 1 y 2 pounds to BO gallons of water or in smaller 
quantities 1 ounce to 2 gallons or 1 rounding teaspoonful to 1 
quart of water. Spray thoroughly all parts of the plant likely 
to be fed upon. 
Powdered derris root or powdered pyrethrum flowers or dusts 
containing these insecticides also have some value as stomach 
poisons for ornamental plants where one does not wish to use an 
arsenical poison. These powders may be dusteu upon the plants 
or applied as a spray by diluting at the rate of 1 pound to 3 to 5 
gallons of water. They act as contact poisons and repellents as 
well as stomach poisons, but will not protect the plants for as 
long a time as lead arsenate against leaf eating insects. 
Stomach poisons may be used against insects such as most 
beetles, grasshoppers, caterpillars, etc. They are not effective 
against plant lice, scale insects, leaf hoppers, various plant bugs, 
etc. 
CONTACT SPRAYS 
Contact sprays are of two kinds. Those used on plants during 
the growing season and known as summer contact sprays, and 
those used on hardy plants while they are in a resting or dor¬ 
mant stage, are known as dormant sprays. 
Summer contact sprays are of many kinds. The most com¬ 
mon ones contain either nicotine, extracts of pyrethrum flowers 
(pyrethrins) or extracts of derris or cube roots (principally 
rotenone) as the principal killing agent in water, alcohols or oils. 
Soaps and the so-called white oils are also effective against some 
insects, such as plant lice, crawling stages of scale insects or 
other young insects. There are so many different kinds of con¬ 
tact sprays and they vary so much in their composition and form¬ 
ulae that general directions are difficult to give. State and Fed¬ 
eral laws require that they be true to label and directions ; there¬ 
fore, they should be used as directed on the containers. 
Contact sprays kill by wetting the surface of the insect to be 
killed. Therefore, the spraying should be thoroughly applied to all 
parts of the plant, both upper and lower leaf surfaces. Many 
contact sprays contain either soap, oils or other materials to make 
the diluted spray wet better. If they do not contain a wetting 
agent or if the dilution with water is rather high they can often 
be made more effective by adding soap. Powdered or dry soaps 
should be used 1 part to about 200 parts of the diluted spray. 
Liquid soap should be used diluted from 2 to 4 times as much as 
the actual amount of soap they contain. Thus, a liquid soap con¬ 
taining 15% actual soap should be added 1 part to 30 to 60 parts 
of the diluted insecticide spray or liquid soap containing 40% 
actual soap should be added 1 part to 80 to 160 parts of the 
diluted insecticide. The concentration of soap will depend upon 
how hard the insects are to kill and whether the plants are tender 
or hardy. 
The insects controlled with summer contact sprays may be 
divided into several groups according to their habits and diffi¬ 
culty of control. These groups are as follows : 
PLANT LICE (also called aphids and green fly), infest many 
different kinds of plants. Soft bodied, whitish, green, brown or 
sometimes almost black in color, usually not more than % inch 
long. Generally found clustered on the under surface of leaves, 
or along the new growth of stems. To control, dip or spray 
