MISCELLANEOUS INSECTICIDE INVESTIGATIONS. 43 
The most promising new insecticide developed during the course 
of the experimental work is arsenate of calcium. This arsenical may 
he 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 4 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= commercial; c. p.=chemically pure; h. m.=homemade.] 
Reference. Table. 
Anthracene emulsion XI. XV 
Anthracene emulsion, arsenate of lead (powder ) XI 
Arsenate of calcium (com. paste) VI, XIII, XIV 
Arsenate of calcium (com. paste), kerosene emulsion XI T I 
Arsenate of calcium (com. paste), lime-sulphur VI. X, XIII, XIV, XVI 
Arsenate of calcium (com. powder) VIII, XI, XIII, XIV 
Arsenate of calcium (com. powder), kerosene emulsion XI 
Arsenate of calcium (com. powder), lime-sulphur XIV 
Arsenate of calcium (c. p. powder) I, III, V 
Arsenate of calcium (c. p. powder), lime V 
Arsenate of calcium (c. p. powder), lime-sulphur II, IV, V 
Arsenate of calcium <h. m. paste) VI, VIII, IX, XIII, X IV 
Arsenate of calcium (h. m. paste), Bordeaux mixture XII 
Arsenate of calcium (h. m. paste), Bordeaux mixture, nicotine sulphate XII 
Arsenate of calcium (h. m. paste), kerosene emulsion XIII 
Arsenate of calcium (h. m. paste), liine-snlphur VI, X, XIII, XIV 
Arsenate of calcium ih. 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 XVTU 
Arsenate of lead (com. paste, kerosene emulsion XIII 
