LIME-SULPHUR A STOMACH POISON FOR INSECTS. 



87 



of lead, 1-50, 2-50, and 3-50, each killed the larvas 2 days sooner than 

 that required by lime-sulphur, 1|— 50. Lime-sulphur, l-|-50, when 

 added to the various strengths of arsenate of lead did not appreciably 

 affect the rate of killing of the arsenate of lead. The amount of feed- 

 ing was reduced in all cases, excepting that of the strongest solution, 

 lot 14, by the addition of lime-sulphur. 



On the lots sprayed with lime-sulphur, 1-50, f-50, H-50, and 3-50, 

 combined with arsenate of lead, 2-50, there was no difference in the 

 length of time required to kill the larvse, 6 days being required in all 

 cases. The same number of days was required by arsenate of lead 

 alone, 2-50, but the rapidity of killing was somewhat increased by the 

 addition of lime-sulphur. 



Experiment V. 



In an experiment to obtain data on the sticking qualities of various 

 sprays, three lots of the regular orchard demonstration strength of 

 lime-sulphur, l|-50, were used. The three lots were thoroughly 

 sprayed and allowed to dry. One lot was then washed for 15 minutes 

 under a shower bath, by placing the twig just above the floor in an 

 inclined position, allowing the water to fall upon it. Another lot was 

 washed 30 minutes in the same manner, while the third lot remained 

 unwashed. 



The same procedure was carried out on three lots of arsenate of 

 lead, 2-50. After the twigs were again thoroughly dry 20 larvae were 

 placed on each. The results of this experiment are to be found in 

 Table V. 



Table V. — Tests of the billing effect of lime-sulphur in comparison with arsenate of lead 



ajter washing of each. 



[Experiment started August 4 



1912, Benton Harbor, Mich., 20 larvae in each lot.] 







Larvae dying in each lot. 



Date of examination. 



Lotl— 



Check 



(un- 



sprayed). 



Lot 2— 

 Lime- 

 sulphur, 

 l|-50; 

 not 

 washed. 



Lot 3— 



Lime- 

 sulphur, 



li-50; 

 washed 15 

 minutes. 



Lot 4— 

 Lime- 

 sulphur, 



1^-50; 

 washed 30 

 minutes. 



Lot 5— 

 Arsenate 

 of lead, 

 2-50; 

 not 

 washed. 



Lot 6— 



Arsenate 



of lead, 



2-50; 



washed 15 



minutes. 



Lot 7— 



Arsenate 



of lead, 



2-50; 



washed 30 



minutes. 













1 

 12 







9 











2 

 4 

 5 

 9 





11 





2 

 2 

 12 

 4 





1 



2 

 8 

 9 





13 





2 

 9 

 7 

 2 



1 



15 - 







2 



17 



1 





77 



19 







4 



21 













4 



29 



2 

 3 

 1 















Sept. 9 















19 . . 





























Total number of dead 



7 



20 

 13 



0.S2 



20 

 15 



1.56 



20 

 13 



0.84 



20 

 0.38 



20 

 11 



1.79 



1 18 

 17 



Square inches of foliage con- 

 sumed. 



111.00 



5.00 



2 escaped. 



