
F, ¢ F. NURSERIES 130 

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 impossible to give 
control methods here for all these insects. Therefore, this brief arti- 
cle is presented on some of the fundamental principles of insect control. 
Difficult cases of insect control should be referred to your State Ento- 
mologist for advice. 
IMPORTANCE OF FEEDING HABITS 
The method of controlling any specific insect is largely determined 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 con- 
trolled by stomach poisons, such as arsenate of lead, 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 powdery material, or in 
a paste form. The powder is usually used at the rate of 114 pounds to 
50 gallons of water or in smaller quantities 1 ounce to 2 gallons or 1 
rounded 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 contain- 
ing these insecticides also have some value as stomach poisons for orna- 
mental plants where one does not wish to use an arsenical poison. 
These powders may be dusted 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. 
