CHAPTER XII. 
INSECT PESTS AND PLANT DISEASES. 
j\ /TOST insect pests and plant diseases are controlled by 
spraying or dusting the infested plants with certain 
chemicals. Hand sprayers can be purchased for the 
spraying of plants, shrubs, and small trees. These spray¬ 
ers are inexpensive and are a real necessity for every 
gardener. Your Forestry Department can handle the 
spraying of larger trees. 
APHIDS OR PLANT LICE. 
Small, soft-bodied insects, generally not much larger 
than the head of a pin. Various colors, green, black, blue, 
purple, etc. They feed by sucking the sap, and when they 
attack the leaves often cause them to curl up and shrivel. 
Aphids attack many kinds of trees, shrubs, and plants. 
Control: Spray with a solution of 1 pint of “Black- 
Leaf 40“ (Nicotine Sulfate) and 4 pounds of laundry soap 
to 100 gallons of water (Formula for spraying smaller 
quantities will be found on the package of “Black-Leaf 
40”). Only the insects actually hit by the spray are killed, 
so the spraying must be very thoroughly done. Several 
sprayings are sometimes required for effective results. 
Sometimes the Aphids can be washed off by repeated 
applications of a strong stream of water from the garden 
hose. On small plants a strong solution of laundry soap 
will often be effective. But Aphides multiply rapidly and 
if all are not killed there will soon be another infestation. 
