548 ANNUAL. REPORT OF THE Off. Doc. 



Paris gi'oen. It is prepared by dissolviug one pound of arsenic anJl 

 four pounds of sal soda (carbonate of soda, washing- soda) in one 

 gallon of water and boiling in an iron vessel fifteen minutes or until 

 the arsenic dissolves. Replace the water lost in boiling and use at 

 the rate of one pint to each fifty gallons of water to which two 

 pounds of freshly slacked lime have been added. With Bordeaux 

 mixture use at the rate of one pint to fifty gallons. 



Arsenate of Lead, operates more slowly than the preceding, but 

 adheres bettor than any other of the arsenical compounds and can 

 be used in large amounts without injury to the most delicate foliage. 

 It may be purchased in a paste form ready for use or it may be pre- 

 pared by dissolving five and one-half ounces of lead acetate (sugar 

 of lead) in two quarts of warm water in a wooden pail, while two 

 ounces of arsenate pf soda (50 per cent, pure) are dissolved in one 

 quart of water in another wooden pail. Pour these solutions into 

 50 to 75 gallons of water and the insecticide is ready for use. 



Hellebore. — Fresh white hellfebore at the rate of one ounce to 

 three gallons of water is milder than the preceding and is useful 

 when an application is needed upon fruits nearly mature, particu- 

 larly currants and gooseberries. 



CONTACT INSECTICIDES. 



Whale Oil Soap Solution. — Whale oil soap containing 12 per cent, 

 of potash Avhen used at one and one-half to two pounds per gallon 

 of hot water for late winter application, is one of the most conven- 

 ient remedies for scale insects and is particularly suited to use upon 

 peach trees, as these are more sensitive, as an over amount of 

 kerosene or petroleum spray has worked injury, especially when 

 applied early in the winter. Fall application of whale oil soap at 

 the above strength will destroy fruit buds for summer use in the 

 control of plant lice, pear psylla, etc.; the maximum strength is 

 about one-fourth pound per gallon of water. 



Mechanical Mixtures of Crude or Refined Petroleum., with water 

 offer the most simple method of application of these oils, but only 

 the special automatic mixing pumps can be employed for the pur- 

 pose. Applications of crude petroleum testing about 43 degrees, 

 Baume scale, or of kerosene, or a mixture of both, have been proved 

 effective when applied just before the buds burst in the spring as a 

 spray for scale insects. The crude ])etroleum remains longer upon 

 the wood than does kerosene and has great insecticidal value. In 

 summer use 15 to 25 per cent, sprayed very lightly so that trees are 

 not completely drenched. 



Kerosene Emulsion., or Petroleum Errv^dsion., is made of hard soap, 

 one-half pound; boiling water, one gallon; kerosene, two gallons, and 

 should be diluted four to fifteen times before applying. Use strong 

 emulsion for dormant wood. For such insects as plant lice, mealy 



