40 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 3 



branches, it might be well to mention the successful use of the material. 



The greatest advance in the perfection of methods for destroying 

 the gypsy moth has been along the line of new spraying devices. Pre- 

 vious to the year 1900 hand pumps mounted on barrels or hogsheads 

 were used for furnishing power. Since that time gasoline engines 

 have been utilized to a greater or less extent, especially in the large 

 fruit-growing districts throughout the United States. This method 

 was tried in the gypsy moth infested territory after the work of sup- 

 pression was resumed in 1905. A gasoline engine with a suitable 

 pump mounted on wagon trucks with a spray tank having a capacity 

 of 300-500 gallons has been employed. The Vermorel or Bordeaux 

 nozzles and lines of i/2-ineh hose were used, and it was necessary to 

 climb tall trees in order to treat them thoroughly. It was not possi- 

 ble to cover very many large trees in a day when an equipment of this 

 sort was used. 



As early as 1895 a steam spraying outfit was devised and used in 

 Prospect Park, Brooklyn, New York, by Mr. J. A. Pettigrew for treat- 

 ing trees for the elm-leaf beetle. With this outfit high pressure was 

 developed, so that the trees were sprayed from the ground. A descrip- 

 tion of the sprayer was published by Dr. L. 0. Howard in an article 

 entitled ''The Use of Steam Apparatus for Spraying," in the Year- 

 book of the United States Department of Agriculture for 1896. 



After Mr. Pettigrew was made Superintendent of Parks of the City 

 of Boston he continued to use a similar outfit for treating elm trees 

 infested with this insect. 



In the spring of 1905 the "solid stream" method of spraying was 

 tested by General S. C. Lawrence of Medford, Mass., the trees treated 

 being badly infested with the gypsy moth. The outfit used was built 

 by the firm of Stephen B. Church of Boston, the power being supplied 

 by a high power gasoline engine. The experiment was entirely sat- 

 isfactor}', and since that time this system of spraying has come into 

 general use on the gypsy moth work. Mr. George H. Kermeen, one 

 of the representatives of this firm, was an early advocate of the method 

 and through his efi^orts many people were interested in its use. 



It should be stated that the successful application of the solid stream 

 spray requires a high power engine, a strong pump equipped with a 

 suitable air chamber and a nozzle constructed in such a manner that 

 the stream will be carried to the top of high trees before it breaks into 

 a mist. For park and woodland work, where trees from 50 to 75 feet 

 in height are to be treated, the best outfits now in use are provided 

 with a ten horse power gasoline engine of the marine motor or auto 

 tj'pe and a triplex pump capable of discharging at least 35 gallons a 



