NICOTINE SULPHATE AS AN OVICIDE AND LARVICIDE. 15 



Seventy-seven per cent of the newly hatched codling-moth larvae 

 placed upon pears sprayed 24 hours previously with a solution of 

 nicotine sulphate 1 : 800 died, but only 33 per cent of those placed 

 upon pears sprayed a week previously died. 



Relative to the control of the codling moth, the following briefly 

 summarizes the more important points herein recorded: About 20 

 per cent of the freshly laid eggs sprayed with a solution of nicotine 

 sulphate 1 : 800 failed to hatch, and one-third of the remaining em- 

 bryos that emerged died before they entered pears sprayed a week 

 previously. Hence about one-half of the eggs and larvae had been 

 destroyed up to the time when the remaining larva? entered the 

 sprayed pears ; a large percentage of the latter larvae died, as about 

 60 per cent of the pears did not become wormy. According to these 

 laboratory results nicotine sulphate does not seem to be efficient 

 against the codling moth, although only one application of it was 

 made; nevertheless its effectiveness would certainly be increased 

 in proportion to the number of its applications and to the amount 

 of rainfall. 



EXPERIMENTS CONDUCTED IN ORCHARDS. 



According to the preceding laboratory results nicotine sulphate 

 would not seem to be efficient against the codling moth. To deter- 

 mine this from the practical viewpoint the following experiments 

 were conducted: 



EXPERIMENTS PERFORMED AT BENTON HARBOR, MICH. 



The experimental work conducted at Benton Harbor consisted in 

 testing the relative efficiency of nicotine sulphate when combined 

 with soap and when combined with soap and arsenate of lead in 

 contrast with the efficiency of arsenate of lead when combined with 

 lime-sulphur at summer strength. The experiments were made in a 

 sod orchard about 50 years old, and each of the four plats selected 

 consisted of 16 trees. 



All of the applications throughout the season were made with the 

 same power sprayer and at a pressure well above 100 pounds. The 

 spray was delivered through the Vermorel type of nozzle. Although 

 the experiments were started with the calyx application, all of the 

 plats, including the check (No. 4), were given the cluster bud 

 application. 



The set of fruit was scattered and rather light, being lightest in 

 plat No. 3, but it was sufficient to give reliable experimental results. 

 In order that trees with as uniform a crop as possible might be 

 secured throughout the different plats, five count trees in each plat 

 were not selected until after the fruit had set. The fallen fruit was 



