EXPERIMENT STATION BULLETINS. 147 



bamboo or to attach it to a length of half-inch gas pipe and send the stream of liquid 

 through the gas pipe. At least fifteen feet of hose should be allowed in order to 

 reach all parts of the tree. 



Never spray a tree when in bloom ; it may kill bees, both wild and hive bees. 



Stone fruits require especially careful treatment; they are easily injured by sprays 

 not properly mixed or prepared. 



INTERNAL POISON FOE INSECTS THAT CHEW, — PARIS GREEN. 



1 



At the head of all the stomach poisons stands Paris green or arsenite of copper. 

 To prepare Paris green for spraying, slake one-pound of well-burned quicklime in 

 hot water and stir in one pound of Paris green. Allow this mixture to stand over 

 night, strain, and then stir it into from 150 to 250 gallons of water. Keep the liquid 

 well stirred while spraying. For most insects, one pound to 200 gallons of water is 

 sufficient, and at this rate it will not injure the plant. Stone fruits, such as peach, 

 plum and cherry, should not receive a spray much stronger than this, but apples, 

 pears, etc., may he sprayed with a mixture considerably stronger, viz., one pound to 150 

 gallons of water. Potatoes may be sprayed with one pound to 100 gallons of water. 

 Paris green is fairly uniform in composition if not adulterated, and is perhaps the 

 safest and surest remedy for chewing insects as a whole. 



DRY METHOD. 



While ordinarily it is most economical to use Paris green in the form of a spray, 

 in some instances, where only a few plants are to be treated or where no pump is 

 available, it is expedient to use it as a dry powder. It should then be mixed at the 

 rate of one pound of the poison to 100 pounds of plaster, flour, or air-slaked lime, 

 and dusted on the plants through a sack of burlaps or some loose, coarse cloth. 

 It is best to make the application in the morning when the dew is on the plants. 

 Never apply dry poisons where the wind can blow the powder into pastures or places 

 where cattle or horses are feeding. 



ARSENATE OF LEAD. 



This poison, although not in general use throughout the country, has several 

 advantages ; it shows where it has been applied ; it is light and does not require 

 such vigorous stirring as Paris green; it does not easily burn the foliage, and it is 

 cheap. To prepare it, dissolve four ounces of arsenate of soda and eleven ounces of 

 acetate of lead, each in a gallon of water. On mixing the two solutions together we 

 shall get a milky precipitate, which should be stirred into 100 gallons of water. 

 It is now ready for spraying. Of course, larger or smaller quantities may be made 

 in the same proportion, and if this preparation does not seem strong enough, it may 

 be applied much stronger with safety. 



Its action is slower than that of Paris green, but the fact that it does not readily 

 burn foliage is an advantage when spraying various kinds of trees with one mixture. 



CONTACT INSECTICIDES, FOR INSECTS WHICH SUCK THEIR FOOD. 



The most effective contact insecticides are kerosene emulsion and whale-oil soap. 

 Kerosene emulsion may be used against all lice (except bark-lice), bugs, etc., which 

 do not succumb to the internal poisons. To be effective it must be very carefully 

 made and conscientiously applied. 



Place two gallons of ordinary kerosene in a warm place, either in a warm room 

 or in the sun, and allow it to become as warm as possible without danger from fire. 

 Boil one pound of laimdry soap or whale-oil soap in a gallon of soft water until 

 completely dissolved. If the water is the least bit hard, "break" it with washing soda. 

 Remove the soap solution from the fire, and while still boiling hot add the kerosene 

 and agitate for ten minutes, or until the oil is emulsified, with a spraying pump, by 

 forcing the liquid back into the vessel from which it was pumped. 



When the liquid is perfectly emulsified it wH appear creamy in color and ^v^ll 

 flow evenly down the side of the vessel. Care should be taken to completely emulsify 

 the oil, and this is accomplished much more easily when the mixture is hot. This 

 strong emulsion may now be readily diluted with water and used, or it may be 

 stored away for future use. When cold it becomes like sour milk in appearance, and 

 should be dissolved in three or four times its bulk of hot water before diluting with 

 cold water. 



