336 journal of economic entomology [vol. 10 



Conclusions 



Nicotine sulphate is a very powerful repellent for caterpillars. They 

 will not ordinarily feed from choice on foliage sprayed with it. Where 

 feeding does take place, the action of the nicotine is apparently rapid 

 and sure, even small bits of foliage sprayed with comparatively weak 

 solutions, where devoured, killing after a short time. To what prop- 

 erty of the spray one may attribute the general sick condition of the 

 caterpillars is discussed in Mr. Mclndoo's paper, page 98. Paralysis 

 of the nerves by the volatile nicotine passing in through the tracheae as 

 he suggests is the most feasible explanation. The volatilization of 

 nicotine sulphate must be very slow as this material is, theoretically, 

 non-volatile. The possibility of the active agent being absorbed by 

 the feet or through the skin and thus carried to the nerve centers is 

 also suggested. 



Series B, For Codling Moth 



The tests of nicotine sulphate for the control of the codling moth 

 were very unsatisfactsry and can hardly be considered good experi- 

 mental data. The immediate cause for failure was an unavoidable late 

 change in plans. The factors which make the test of little value are 

 as follows: The orchard tract available for the test consisted of a run- 

 down orchard of mixed varieties with their necessary individual 

 variations. No comparison was made against the standard lead 

 arsenate application. The nicotine sulphate was used in combination 

 with lime-sulphur instead of soap. The season was a very backward 

 one and the generations of the codling moth were very much delayed. 

 A summary of the test is included in this paper that one may judge 

 the results for whatever value they may have. 



Four applications were made: 1, The calyx spray, May 10; 2, When 

 eggs of first generation were deposited, June 16; 3, When first adults 

 of second generation appeared, August 2; and 4, When majority of 

 second generation moths were depositing eggs, September 8. 



The following materials were used at each application: 



1. Niagara dust sulphur 85 per cent plus Corona lead arsenate 15 per cent, as a 

 dust. 



2. Black Leaf 40, 1-400 plus lime sulphur 32° B., 1-35. 



3. Pratt's Nicotine 40, 1-800 plus lime sulphur 32°, 1-35. 



4. Black Leaf 40, 1-1200 plus lime sulphur 32°, 1-35. 



While none of the materials gave satisfactory control, the compara- 

 tive results are interesting. In the check, there were 29.65 per cent of 

 wormy apples. Nicotine sulphate 1-1200 and 1-800 show but slight 

 control, having respectively 26.8 and 26 per cent of wormy apples. 



