2 BULLETIN 938, U. S. DEPARTMENT OF AGRICULTURE. 



sulphate did not control the codling moth as well as did lead arsenate, 

 and that its control was unsatisfactory on all of the plats sprayed, 

 except one. The Bureau of Entomology also conducted some field 

 experiments during the season of 1917 in three important apple 

 regions in the United States, the first of these being in the Lake region 

 at Benton Harbor, Mich. ; the second one in the mountainous region 

 at Grand Junction, Colo. ; and the third one in the semiarid region 

 at Roswell, N. Mex. In the first region the experiments were carried 

 on by Mr. Simanton; in the second one by Mr. Plank; and in the 

 third one by Mr. Fiske. All of the laboratory experiments were per- 

 formed by Dr. Mclndoo. 



Lovett (5) reports that nicotine sulphate with soap is an effective 

 ovicide for the codling moth. Excepting this experiment, in which 

 only 26 codling-moth eggs were used, no other experiments, either in 

 orchards or in a laboratory, have ever been conducted to determine 

 how nicotine sulphate checks the work of the codling moth, although 

 Feytaud (<?), testing the effects of pure nicotine and soap in the labo- 

 ratory upon the eggs of two moths belonging to the same family, 

 ascertained that about 75 per cent of the embryos in the eggs tested 

 were aborted during the last stage of development, while the remain- 

 ing eggs hatched. 



The first portion of the present paper embodies the results obtained 

 in the laboratory concerning the effects of nicotine sulphate as an 

 ovicide and larvicide on the codling moth and three other insects. 

 The second portion of this study deals with the effectiveness of nico- 

 tine sulphate as compared with the efficiency of arsenate of lead for 

 controlling the codling moth in orchards. 



EXPERIMENTS CONDUCTED IN THE LABORATORY. 



In order to throAv some light on how nicotine sulphate checks the 

 work of the codling moth the following tests were performed : 



EFFECTS OF NICOTINE SULPHATE 3 ON EGGS AND NEWLY HATCHED LARV^ OF 



THE SILKWORM MOTH. 



This investigation was begun in September, 1916, when it was too 

 late to obtain codling-moth eggs or fresh eggs of any other insect ; 

 so the study was begun by using eggs of the silkworm moth {Bomby.v 

 m.ori L.), 10,000 of which were 14 months old, 2,000 of which were 

 from 1 to 6 days old, and 10,000 of which were 3 months old. 



EFFECTS OF NICOTINE SULPHATE ON EGGS OF THE SILKWORM MOTH. 



The eggs just enumerated were divided into several lots, and some 

 of these lots were sprayed with nicotine sulphate (1:800 --)- fish-oil 



8 Throughout this paper reference is made to "nicotine sulphate" containing 40 per 

 cent of nicotine. 



