6 



BULLETIN 938, U. S. DEPARTMENT OF AGRICULTURE. 



Three apples, after having been dipped into a solution of nicotine 

 sulphate 1 : 400+soap, were placed in three batten?- jars containing 

 many unsprayed eggs. A later examination showed that 49 eggs 

 had been deposited on the apples, 47 of which had hatched. These 

 decayed apples contained 39 burrows, and finally two moths were 

 found in each of two jars. A repetition of this experiment resulted 

 in obtaining no moths from three dipped apples and only two from 

 three control apples. 



Table I. — Effects of nicotine sulphate on codling -moth eggs (1 and 2 dags old) 

 laid on fruit-tree foliage in laooratorg. 



Experiment No. 



Strength of nicotine-sulphate solution 

 used, and control. 



Number 



of eggs 



sprayed. 



Eggs 

 hatched. 



Embryos totally 

 aborted. 1 unde- 

 veloped. 





f 1 :400 



15 

 33 

 15 

 29 



38 

 75 



52 

 64 



' 116 

 158 

 213 

 56 



Per cent. 

 53.3 

 66.7 

 63.7 

 96.6 



92.1 

 98.7 



63.5 

 95.3 



47.4 

 49.2 

 79.8 

 94.4 



Percent. \ Per cent. 

 46.7 





Jl:800 



33.3 





1 1 : 800+soap 



36 3 





[Control 



3 4 



2 



fl:l,000+soap 



7.9 





(Control 



fl:800 



1.3 

 13.4 23.1 



3 



\Control 



3.1 | 1.6 





fl :400 



52.6 ' 





J 1 : 400+soap 



47.4 1 3.4 





|l:800+soap 











iControl 



5. 6 









To test the value of nicotine sulphate as an ovicide for codling- 

 moth eggs, two experiments were started by E. H. Siegler, ento- 

 mological assistant, June 5, 1918, at the bureau's field laboratory in 

 Tvallingford, Conn. In each experiment the eggs were deposited 

 on apple-tree foliage by moths confined in oviposition jars. All of 

 the treated eggs were thoroughly immersed in a solution of nicotine 

 sulphate 1 : 800 plus common laundry soap (3 pounds to 50 gallons 

 of water). After treatment each leaf was placed in a separate jar, 

 with an apple as food for the larvae as they hatched. 



Experiment Xo. 1. — In this experiment the eggs were deposited 

 June 3, and at the time of dipping them into the spray solution many 

 had advanced to the red-ring stage. Seven leaves bearing 310 eggs 

 were treated, while one leaf bearing 190 eggs was left untreated 

 as a check. The results obtained show that out of 310 eggs treated, 

 296, or 95.48 per cent, hatched; out of 190 untreated eggs 96.84 per 

 cent hatched. Many of the larvae entered the apples and commenced 

 feeding vigorously therein. 



Experiment No. 2. — The eggs employed in this test were deposited 

 June 4, and at the time of dipping them into the nicotine-soap solu- 

 tion none had advanced to the red-ring stage. Out of a total of 37 

 eggs, 35, or 94.59 per cent, hatched; out of 11 untreated eggs, 11, or 



