April, '09] .lOURXAL OF ECONOMIC ENTOMOLOGY I55 



tancy of peach growers to use arsenieals upon peach trees has been 

 due to their fear of doing injury to the foliage or fruit, a fear which 

 in the past, with the use of Paris green, has been well groimded. 

 The advent of arsenate of lead as an insecticide, with its increased ad- 

 hesiveness and greater safety to the tree, makes the practicability of 

 peach-spraying for this pest seem more promising. 



An experiment conducted by the writer this season has given ad- 

 ditional and convincing evidence that injury from the curculio can be 

 largely prevented upon peach by proper spraying with a dilute solu- 

 tion of arsenate of lead, and this at a cost and with results which makes 

 the treatment a practical operation to every peach grower in the ter- 

 ritory where this insect occurs as a pest. Although this report is in- 

 tended only as a preliminary one upon this subject and is not presented 

 as a final recommendation to growers, it is thought that a brief ac- 

 count of the investigations thus far conducted and of some of the facts 

 gathered would be timely at this meeting. The results thus far may 

 be also of interest since the plan is, in the main, similar to one being 

 carried out by Professor Quaintance of the Bureau of Entomology. 



The Spraying 



The spraying experiment was conducted upon a block of 1195 six- 

 year-old Elberta trees belonging to the Olden Fruit Company at 

 Olden, Missouri, and forming a portion of one of the most extensive 

 fruit plantings in the Ozarks, comprising in all about 1,800 acres. 

 The spraying was done with a gasoline power outfit. The spray used 

 was Swift's arsenate of lead, costing about 12 cents per pound, and 

 the average amount required for a very thorough application was 

 about two gallons per tree, or only about one cent per tree per ap- 

 plication for insecticide and only between two and three cents per 

 tree per spray when cost of application was also included. 



Upon all of the principal plats, containing from 32 to 249 trees, 2 

 pounds of the paste lead were used per 50 gallons, with the addition 

 of 4 pounds of quick lime for the purpose of neutralizing any free 

 arsenic which might happen to be present. To determine the effect of 

 an increased amount of the lead arsenate upon the tree, a number of 

 small plats were given varying amounts of arsenate of lead, both with 

 and without the addition of lime. The season covered by the spraying 

 was one of unusual rainfall. In the month of April 9.06 inches and 

 in the month of ]May 10.24 inches were the recorded precipitation at 

 the orchard, while the month of June gave 15 days in w^hich rain 

 fell. Not only were these conditions unfavorable for the best results 

 but several damaging late frosts reduced the crop to a very light 



