﻿32 



BULLETIN 1147, U. S. DEPARTMENT OF AGRICULTURE. 



ducting the mortalities of the controls and basing the average per- 

 centages of toxicity on the mortalities of the third, sixth, tenth, and 

 twentieth days, the results for all these insects are: Sample 69, 45; 

 sample 69A (sample 69 plus 0.5 gram lime), 32.7; sample 69B (sample 

 69 plus 1 gram lime), 29.1 ; sample 69C (sample 69 plus 2 grams lime), 

 26.5. 



Table 14. — Effect on toxicity of adding lime to arsenicals on 4 species of insects, 1919 and 



1920. 



39 

 39C 



69 

 69C 



64 

 64C 



39 

 39 L 



57 

 57 L 



Arsenicals and control. 



Commercial acid lead arsenate. 

 Sample 39 plus lime (2 grams) . . 

 Laboratory calcium arsenate. . . 

 Sample 69pluslime(2 grams) . . 



Commercial Paris green 



Sample 64 plus lime (2 grams). . 

 Commercial acid lead arsenate. 

 Sample39(leavessprayed with 



sample 11 lime) 



Commercial calcium arsenate. . 

 Sample 57 (leaves sprayed with 



sample 1 1 lime) 



Control with food 



Percentage of insects dead within— 



3 days. 



91.0 

 69.0 

 32.7 

 9.4 

 100.0 

 57.0 



11.0 

 6.3 

 5.4 

 1.8 



30.7 

 1.8 



20.3 



20.5 

 7.5 



2.3 

 .0 



18.1 

 18.0 

 42.3 

 33.3 

 65.7 

 23.4 



.6 



21.0 

 14.0 

 12.0 



7.0 

 15.0 



8.0 



.0 



35.3 

 26.8 

 23.1 

 12.9 

 52.8 

 22.5 



6 days. 



100.0 

 93.0 

 53.8 

 15.1 



79.0 



72.8 

 38.3 

 39.7 

 14.4 

 85.2 

 44.2 

 79.0 



78.7 

 30.4 



12.2 

 .0 



82.2 

 81.1 

 91.6 

 91.2 

 99.0 

 S6.0 



58.0 

 40.0 

 44.0 

 23.0 

 62.0 

 56.0 



12.0 



78.3 

 63.1 

 57.3 

 35.9 

 86.6 

 66.3 



Arsenicals and control. 



Percentage of insects dead 

 within 10 days. 



0? 



En 



Toxicity for— 





39 

 39C 



69 

 69C 



64 

 64C 



39 

 39 L 



57 

 57 L 



Commercial acid lead arsenate 



Sample 39 plus lime (2 grams) 



Laboratory calcium arsenate 



Sample 69 plus lime (2 grams) 



Commercial Paris green 



Sample 64 plus lime (2 grams) 



Commercial acid lead arsenate 



Sample 39 (leaves sprayed with 



sample lllime).-- 



Commercial calcium arsenate 



Sample 57 (leaves sprayed with 



sample 1 1 lime) 



Control with food 



100.0 

 59.6 

 22.6 



99.3 

 82.9 

 66.0 

 30.2 

 100.0 

 99.4 

 93.6 



95.1 

 66.0 



36.4 

 2.6 



100.0 

 100.0 

 98.8 

 100.0 

 100.0 

 100.0 



99.8 

 94.3 

 74.8 

 50.9 

 100.0 

 99.8 



97.0 

 87.3 

 48.7 

 15.7 

 100.0 

 78.7 



61.0 

 42.5 

 37.0 

 15.5 

 72.0 

 48.5 

 64.3 



64.7 

 34.6 



66. 8 

 66.4 

 77.6 

 74.8 

 88.2 

 69. S 



39.5 

 27.0 

 28.0 

 15.0 

 38.5 

 32.0 



66.1 

 55.8 

 47.8 

 30.2 

 74.7 

 57.2 



i Based on mortalities for third and sixth days only, because these controls, confined in small cases, 

 lived for only 8.4 days on an average. 



In 1920 these experiments were repeated on a larger scale. The 

 following data are not given in Table 14: Silkworms, 2 sets (each of 

 50); webworms (H. cunea), 1 set (variation 136-194: 145); tent 

 caterpillars, 3 sets (198-385: 280); and honeybees, 2 sets (each of 

 50) . The percentages given for samples 69 and 69C are taken from 

 the 1919 results, and should be compared only roughly with the other 

 percentages given in Table 14. Reference to this table shows that 



