MISCELLANEOUS INSECTICIDE INVESTIGATIONS. 



43 



The most promising new insecticide developed during the course 

 of the experimental work is arsenate of calcium. This arsenical may 

 be manufactured at less cost than arsenate of lead or may be 

 readily prepared at home as described on page 30. During the sea- 

 sons of 1912 and 1913 arsenate of calcium gave encouraging results. 

 In 1914 a commercial arsenate of calcium paste in combination with 

 lime-sulphur gave very satisfactory control of the codling moth. 

 While arsenate of calcium may have certain limitations, it will doubt- 

 less prove of value for the control of chewing insects on certain host 

 plants. 



Arsenate of iron and arsenate of zinc are not as satisfactory as arse- 

 nate of lead. 



Arsenite compounds are dangerous to use on tender foliage. In 

 some instances, however, it may be possible to prevent foliage injury 

 somewhat by combining the soluble arsenic with lime. 



Sodium-sulphur and potassium-sulphur compounds gave fairly sat- 

 isfactory control of the San Jose scale, in some instances equaling 

 lime-sulphur solution. They may readily be prepared at home with- 

 out the use of heat. 



KEY TO THE TABLES OF INSECTICIDES AND COMBINATION SPRAYS 

 USED IN THIS BULLETIN. 



[Com=commereial; c. p.=chemically pure; h. m.=homemade.] 



Reference. Table. 



Anthracene emulsion XI, XV 



Anthracene emulsion, arsenate of lead (powder) XI 



Arsenate of calcium 

 Arsenate of calcium 

 Arsenate of calcium 



Arsenate of calcium 

 Arsenate of calcium 

 Arsenate of calcium 

 Arsenate of calcium 

 Arsenate of calcium 

 Arsenate of calcium 

 Arsenate of calcium 

 Arsenate of calcium 

 Arsenate of calcium 

 Arsenate of calcium 

 Arsenate of calcium 

 Arsenate of calcium 



com. paste) VI, XIII, XIV 



com. paste), kerosene emulsion XIII 



com. paste), lime-sulphur VI, X, XIII, XIV, XVI 



com. powder) VIII, XI, XIII, XIV 



com. powder), kerosene emulsion XI 



com. powder), lime-sulphur XIV 



c. p. powder) I, III, V 



c. p. powder), lime V 



c. p. powder), lime-sulphur II, IV, V 



h. m. paste) VI, VIII, IX, XIII, XIV 



h. m. paste), Bordeaux mixture XII 



m. paste), Bordeaux mixture, nicotine sulphate XII 



h. m. paste), kerosene emulsion XIII 



h. m. paste), lime-sulphur VI, X, XIII, XIV 



h. m.), self-boiled lime-sulphur XIII 



Arsenate of iron (c. p. powder) I, III, V 



Arsenate of iron (c. p. powder), lime V 



Arsenate of iron (c. p. powder), lime-sulphur II, IV, V 



Arsenate of iron (h. m. paste) I, III, V 



Arsenate of iron (h. m. paste), lime V 



Arsenate of iron (h. m. paste), lime-sulphur II, IV, V 



Arsenate of lead (com. paste) I, III, V, VI, VII, VIII, IX, XIII, XIV, XV 



Arsenate of lead (com. paste), barium tetrasulphid XVIII 



Arsenate of lead (com. paste), kerosene emulsion XIII 



