MISCELLANEOUS INSECTICIDE INVESTIGATIONS. 



13 



Table VI. — Tests of the killing effect on the tent caterpillar of arsenate of calcium, alone 

 and combined with lime-sulphur, in comparison with arsenate of lead. 



[Experiment started May 17, 1913, Benton Harbor, Mich.; 50 larvae in each lot.] 









Larvae dying in each lot. 









Arsenate of cal- 



Arsenate of cal- 



Arsenate of cal- 







Arsenate of lead, 



cium (home- 



cium (home- 



cium (com- 







2 to 50. 



made,!), 0.81b. 



made, 2), 0.81b. 



mercial paste), 









to 50. 



to 50. 



1 J to 50. 





Check 































sprayed). 





3 





3 





3 





3 



Dates of examination. 







si 



3 d 



IflO 



S ° 





.a 

 a, 



3 d 

 fi ° 





Si 



& 

 3o 



via 



8 ° 





si 



ft 

 3 d 









2^:' 



CD 





CD 



3 ;*' 



CO 



SJ 







a 



o 



si 



a 

 o 



Si 



a 

 o 



si 



a 

 o 



.a 







<j 



£ 



< 



£ 



< 



£ 



-<1 



£ 























o 





<N 



CO 



■* 







<N 



CO 



** 



lO 



to 





00 

































+3 









4^ 









O 



o 



o 





o 



o 



o 



o 



o 



o 





o 



o 





i-l 



1-1 



hI 



h-1 



i-l 



i-l 



i-l 



Hi 



I-l 



Hi 



Hi 



Hi 



Hi 



h! 



May 20 



1 

 2 

 1 



1 

 1 







42 

 8 



45 

 5 



16 



27 



7 



36 

 12 

 ? 



38 

 12 



27 

 23 



30 

 18 



2 



33 

 17 



20 

 20 

 10 



35 



15 



43 



7 



28 



May 22 



18 



May 24 



4 



May 31... 































































Total number dead 



4 



2 



50 



50 



50 



50 



50 



50 



50 



50 



50 



50 



50 



50 









5 



5 



7 



7 



5 



5 



7 



5 



7 



5 



5 



7 



Square inches foliage con- 

































8.10 



6.75 



0.04 



0.04 



0.01 



0.05 



0.06 



0.02 



0.04 



0.06 



0.02 



0.06 



0.0b 



0.03 







Arsenate of calcium, commercial (paste), used at the rate of 1| 

 pounds to 50 gallons killed all the larvae in 5 days with 0.05 and 

 0.06 square inch of foliage consumed. The same preparation com- 

 bined with lime-sulphur killed in 7 days with 0.03 square inch of 

 foliage consumed. 



It will be noted that when lime-sulphur was used with the poison, 

 less foliage was consumed. 



Experiment VII. 



LEAD CHROMATE VERSUS ARSENATE OF LEAD AGAINST THE LARV^I OF FOUR SPECIES 



OF INSECTS. 



Experiments were conducted with lead chromate, commercial and 

 homemade, used at various strengths in comparison with arsenate of 

 lead used at the rate of 2 pounds to 50 gallons of water, against four 

 species of insects, Eriocampoides cerasi Peck, Hypliantria cunea, 

 Halisidota caryae Harris, and Datana ministra Drury. The results of 

 these experiments are given in Table VII. 



Neither the commercial nor homemade lead chromate was very 

 effective against the pear slug (Eriocampoides cerasi), 6 larvae living 

 through to pupation in each case, and almost as much foliage was 

 consumed as on one of the checks. Arsenate of lead killed 8 of the 

 larvae in 3 days. The other 2 larvae escaped. Nine of the larvae 

 pupated in each of the two unsprayed lots. 



