84 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 

 Experiment II. 



In order to obtain further data on the killing effect of lime-sulphur 

 another experiment was started July 30, using different strengths of 

 lime-sulphur as given in Table II. 



Table II. — Tests of the hilling effect of lime-sulphur on the fall webworm. 

 [Experiment started July 30, 1912, Benton Harbor, Mich.; 20 larvae in each lot.] 





Larvae dying in each lot. 



Date of 

 examination. 



Larvae dying in each lot. 



Date of 

 examination. 



Lot 



1— 

 Check 



(un- 

 spray- 



ed). 



Lot 

 2— 

 Lime- 

 sul- 

 phur, 

 14-50. 



Lot 

 3— 

 Lime- 

 sul- 

 phur. 

 3-50,' 



Lot 

 4— 

 Lime- 

 sul- 

 phur. 

 6-50. 



Lot 

 5i— 

 Arse- 

 nate 



of 

 lead, 

 2-50. 



Lot 

 1— 



Check 

 (un- 



spray- 

 ed). 



Lot 



Lime- 

 sul- 

 phur, 

 14-50. 



Lot 

 3— 

 Lime- 

 sul- 

 phur, 

 3-50. 



Lot 

 4— 

 Lime- 

 sul- 

 phur, 

 6-50. 



Lot 

 5i— 

 Arse- 

 nate 



of 

 lead, 

 2-50. 



Aug. 1 













Aug. 14 





2 









2 .. 









15 











3 





2 









20 













4... 





1 

 1 



3 

 5 

 3 

 8 

 1 



6 



"u 



25 













5 





1 



29 













6 









Total num- 

 ber dead. . 

 Number days re- 

 quired to kill 













7 



1 



1 

 3 

 2 

 2 

 4 

 1 

 2 



9 

 4 

 4 



1 



20 



15 



1.21 



20 



12 



0.65 



20 



9 



0.34 





8 



20 



9 







10 









9 



11... 





1 







Square inches foli- 

 age consumed . . . 



40.00 





12 









0.83 



13 























' Arsenate of lead was used in lot 5 for comparison with the lime-sulphur solution. 



In this experiment 15 days were required by lime-sulphur, H-50, 

 to kill the 20 larva?, as against 9 days required by arsenate of lead, 

 2-50. Twelve days were required by lime-sulphur, 3-50, while lime- 

 sulphur, 6-50, killed the 20 larvae in the same length of time required 

 by arsenate of lead, 2-50. The check lot was discontinued at the 

 end of 30 days, when 1 larva was recorded dead and 40 square inches 

 of foliage consumed. It was found in this test that the number of 

 square inches of foliage consumed decreased about one-half as the 

 strength of the lime-sulphur was doubled, the largest amount being 

 1.21 square inches. The amount consumed on the arsenate-of-lead 

 lot was 0.83 of a square inch. 



Experiment III. 



In Table III are shown the comparative results of a dosage test 

 consisting of seven different strengths of lime-sulphur varying from 

 ^-50 to 6-50, and four different strengths of arsenate of lead varying 

 from ^-50 to 5-50. 



