18 



BULLETIN 938, U. S. DEPARTMENT OF AGRICULTURE. 



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

 picked fruit from experimental plats at Roswell, N. Mex., 1917. 



Plat 



No. 



Number of applications and formula of each. 



Fruit record. 



Total 

 number 

 of apples 

 exam- 

 ined. 



Fallen 



apples 



free from 



worms. 



Har- 

 vested 

 apples 

 free from 

 worms. 



Total 



apples 



free from 



worms. 



5 applications of 1 pound of powdered arsenate of lead 

 to 50 gallons of water 



5 applications of 1 pound of powdered arsenate of lead 

 to 50 gallons of water + nicotine sulphate (1:800)+ j 

 pound of laundry soap 



5 applications of nicotine sulphate (1:800)+ 3 pound of 

 laundry soap to 50 gallons of water 



TJnsprayed 



a 6, 170 



« 14, 401 



Per cent. 

 93.64 



85.55 



88.01 

 52.06 



Per cent. 

 97.66 



93.43 

 50.01 



Per cent. 

 96.88 



91.94 

 51.53 



3 On 4 trees. 



« On 12 trees. 



From Table VII it is seen that the trees sprayed with nicotine 

 sulphate (plat No. 3) yielded a crop of apples 92 per cent sound, 

 while those sprayed with arsenate of lead (plats Nos. 1 and 2) yielded 

 a crop 97 per cent sound, and that the addition of nicotine sulphate to 

 the arsenate of lead mixture (plat No. 2) did not materially increase 

 the percentage of sound fruit. 



CONCLUSIONS FROM FIELD EXPERIMENTS. 



According to the work conducted during the season of 1917, it is 

 shown that nicotine sulphate "l : 800 with soap gave a fair degree of 

 control for the codling moth at Benton Harbor, Mich., and at Ros- 

 well, N. Mex., but that it was not as effective as 1 pound of powdered 

 arsenate of lead to 50 gallons of water; and also that there was no 

 practical advantage in combining arsenate of lead and nicotine sul- 

 phate in sprays designed to control the codling moth. Of course it 

 is well known that nicotine sulphate controls aphids on fruit trees, 

 but this phase of the subject is not considered in this paper. At 

 Grand Junction, Colo., where the infestation was much heavier, nico- 

 tine sulphate 1 : 800 without soap was inefficient against the codling 

 moth. 



