MISCELLANEOUS INSECTICIDE INVESTIGATIONS. 29 



Table XVI. — Sound and wormy apples from sprayed and unsprayed plats — Contd. 











Condition of fruit. 





Plat 



Treatment. 



Tree 

 No. 











num- 











ber. 





Wormy. 



Sound. 



Total. 



Per cent 

 sound. 



II 



Arsenate of lead (paste), 2 pounds to 50 gallons 



1 



29 



3,777 



3,806 



99.24 





lime-sulphur solution. 



2 



12 



2,399 



2,411 



99.59 







3 



28 



5,146 



5,174 



99.46 







4 



13 



3,833 



3,846 



99.66 







5 



26 



3,972 



3,998 



99.35 





Plat total 



6 



26 



4,757 



4,783 



99.46 







134 



23,884 



24,018 



99.44 











III-V.. 



1 



1,548 



3,907 



5,455 



71.62 







2 



3,208 



5,556 



8,764 



63.40 







3 



2,342 



5,682 



8,024 



70.81 







4 



2,432 



4,116 



6,548 



62.86 







5 



2,635 



3,722 



6,357 



58.55 







6 



2,385 



1,566 



3,951 



39.64 







7 



2,902 



2,197 



5,099 



43.09 





Plat total 



8 



2,312 



1,356 



3,668 



36.94 







19, 764 



28, 102 



47,866 



58.71 











As will be noted in Table XVI, out of 29,269 apples from the plat 

 sprayed with, arsenate of calcium 98.79 per cent were free from cod- 

 ling moth. The fruit examined on Plat II, 24,018 apples, sprayed 

 with arsenate of lead, was 99.44 per cent free from the codling moth. 

 The unsprayed trees yielded 47,866 apples, of which but 58.71 per 

 cent were free from worms. 



It will thus be seen that the arsenate of calcium compared very 

 favorably with the arsenate of lead, and since it can be produced 

 more cheaply than the lead arsenate it would appear to have distinct 

 value. The foliage in Plat I was as healthy appearing as in Plat II 

 throughout the season, and, further, the fungicidal value of lime- 

 sulphur was practically the same, whether arsenate of calcium or 

 arsenate of lead was used. While arsenate of calcium has not been 

 sufficiently tested to recommend it for general use, yet it would seem 

 that this arsenical will probably serve as a satisfactory and cheap 

 substitute for arsenate of lead. Arsenate of calcium may be manu- 

 factured either in the paste or powdered form or made at home in the 

 paste form. 



HOMEMADE ARSENATE OP CALCIUM. 



Arsenate of calcium may be prepared at home from various chem- 

 icals, the more important being arsenic acid and lime, sodium arsenate 

 and calcium chlorid, sodium arsenate and calcium acetate, etc. 

 Potassium dihydrogen arsenate may be substituted for the sodium 

 arsenate, but is more expensive and would have no distinct advan- 

 tages over the latter. 



The logical way to make arsenate of calcium is by combining 

 arsenic acid with lime, but at the present writing arsenic acid can 



