88 



DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



The washing made practically no difference in the killing effect of 

 the lime-sulphur spray, the time of killing varying from 13 to 15 days, 

 and the amount of foliage consumed varying from 0.82 to 1.56 square 

 inches. In the case of arsenate of lead, however, the killing effect was 

 considerably retarded. The length of time required to kill all the 

 larvae when the foliage was unwashed was 7 days; when washed 15 

 minutes, 11 days; when washed 30 minutes, 17 days. The amount 

 of feeding was 0.38, 1.79, and 5 square inches, respectively. 



Experiment VI, 



To compare the killing effect of commercial lime-sulphur and home- 

 boiled lime-sulphur, an experiment was conducted in which two lots 

 of each kind were used at the strength of H-50. The commercial 

 products tested 33° Baume and the home-boiled 30° Baume. The 

 results are shown in Table VI. 



Table VI. — Tests of the killing effect on the fall webworm of lime-sulphur, commercial 



and home-boiled. 



[Experiment started Aug. 27, 1912, Benton Harbor, Mich., 20 larvae in each lot.] 





Larvae dying in each lot. 



Date of examination. 



Lot 1 



(20 larvae)— 



Check (un- 



sp rayed). 



Lot 2 



(20 larvae)— 



Commercial 



lime-sulphur. 



14-50. 



Lot 3 

 (20 larvae)— 



Commercial 



lime-sulphur, 



1J-50. 



Lot 4 



(20 larvae)— 



Home-boiled 



lime-sulphur, 



1J-50. 



Lot 5 

 (20 larvae)— 

 Home-boiled 

 lime-sulphur, 



l|-50. 



Aug. 30 









1 

 3 

 7 

 6 

 3 





Sept. 1 





6 



7 

 7 



4 

 9 

 6 



1 



5 



4 





6 



6 





9 



9 







19 



1 

 5 







Oct. 18 





















Total number dead 



Number of days required to kill 

 Square inches bf foliage consumed . 



6 

 116.00 



20 



9 



1.19 



20 



12 



1.28 



20 



12 



3. 05 



20 



9 



4.38 



It was found that the commercial and the home-boiled lime-sulphur 

 killed all the larvae in the same average length of time. However, the 

 rapidity of killing was slightly greater, and the amount of foliage 

 consumed less, where the commercial material was used, due probably 

 to the fact that the commercial solution was somewhat stronger, which 

 the Baume tests would indicate. 



Experiment VII. 



Lime-sulphur, 1^-50, was tried out on a limited number of pear- 

 slug larvae (Eriocampoides cerasi L.), since only a few were available 

 for this test. As in all the experiments, the insects were not placed 

 upon the leaves until the spray had thoroughly dried. The results 

 are shown in Table VII. 



