NICOTINE SULPHATE AS AN OVICIDE AND LARVICIDE. 



17 



Table VI. — Codling-moth injury as shown by examination of both fallen and 

 picked fruit from experimental plats at Grand Junction, Colo., 1917. 





Formula of insecticide. 



Number of applications. 



Total 

 number 



of 

 apples 

 exam- 

 ined. 



Fallen 



apples 



free from 



worms. 



Har- 

 vested 

 apples 

 free from 

 worms 



Total 



Plat No. 



For 



first 



brood. 



For 

 second 

 brood. 



Total. 



apples 

 free from 

 worms. 



2 



1 pound of powdered arse- 

 nate of lead to 50 gallons 



4 

 4 



4 



3 



4 

 13 



2 

 2 



2 



2 

 3 

 2 



6 

 6 



6 



5 

 7 

 5 



23,508 

 29,881 



24,003 



38, 874 

 47, 773 

 37,628 

 33, 882 



Per cent. 



37.75 

 17.32 



40.97 

 48.28 



Per cent. 



72.16 

 58.33 



84.17 

 82.31 



Per cent. 

 62.09 



3 

 4 



Nicotine sulphate (1:800). . 



1 pound of powdered arse- 

 nate of lead to 50 gallons 

 of water plus nicotine 

 sulphate (1:800) 



37.% 



67.50 



8 



1 pound, of powdered arse- 

 nate of lead to 50 gallons 



73.49 



9 





47.74 



85.53 



76.53 



10 





22.83 

 7.36 



60.69 

 15.01 



46.33 



14 and 15 



Check (unsprayed) 





8.72 















i All three were cover applications, the calyx application being omitted. 



Although the results in the preceding table vary considerably, it is 

 seen nevertheless that nicotine sulphate when used alone was ineffi- 

 cient (plat No. 3). 



EXPERIMENTS PERFORMED AT ROSWELL, N. MEX. 



The experimental work conducted at Roswell consisted in a com- 

 parison of the efficiency of nicotine sulphate with that of arsenate of 

 lead alone and also with that of arsenate of lead combined with nico- 

 tine sulphate. For this purpose four plats, lying in a 640-acre tract 

 of apple trees, were selected ; they were similar in all respects and the 

 trees, about 20 years old, were of the Ben Davis variety. Following 

 the regular 5-spray schedule, all the plats, except the check (No. 

 4), were sprayed on the following dates: April 25, May 15, June 14, 

 July 18, and August 14. During the first application about 21 

 gallons of spray material were applied to each tree, but during each 

 subsequent application only about 17 gallons per tree were used. 

 Bordeaux nozzles were used for the calyx application and a mist 

 type for the other applications. A power sprayer, holding 200 

 gallons, was employed, and the pressure was maintained at 200 

 pounds with three leads of hose. 



During these experiments the dates and amounts of rainfall are 

 as follows: May 6, 0.23 inch; July 19, 0.03 inch; July 20, 0.03 inch; 

 August 1, 0.54 inch; August 2, 0.47 inch; August 15, 0.15 inch; 

 August 17, 0.60 inch; and August 18, 0.93 inch, giving a total of 

 2.98 inches. 



The details pertaining to the plats, formulas of application, and 

 results of the foregoing experiments are given in Table VII. 



