21 



Mr. French stated that a fruit grower near Carbondale, 111., had 

 been in the habit of spraying his apple trees eight times during the 

 season with white arsenic and soda (carbonate of soda), and for the 

 past four years had found only an occasional wormj^ apple. Some 

 trees of the Winesap variety were sprayed last summer eight times 

 with arsenate of lead, using 3 pounds to 50 gallons of water, and the 

 fruit on these trees was one-fourth to one-half smaller than that on 

 the trees treated with the other material. 



Mr. Sanderson thought that this might be due to the fact that 

 arsenate of lead would adhere better to the fruit, and that the trees 

 had been oversprayed. He also spoke of the necessity of making 

 accurate counts of all the wormy fruit and taking into consideration 

 the apples that dropped to the ground early in the season, as well as 

 those found on the trees at the time of picking, and gave the follow- 

 ing summary of his experiments in Delaware: 



(1) Arsenate of lead (disparene) , 1 pound to 50 gallons, gives from one-third to 

 one-half more in perfect picked fruit than arsenites of lime or soda, Paris green, 

 or green arsenoid. 



(2) Paris green or green arsenoid, 1 ponnd to 160 gallons, and arsenites of lime 

 or soda. 1 gallon to 160 gallons, are practically of equal value. 



(3) The addition of more arsenite than the above strength is unwarranted. 



(4) Spraying three times does not give enough benefit to warrant the third 

 spraying if the first two are properly made. 



(5) It is doubtful whether the addition of adhesives is profitable. 



(6) The addition of 15 per cent or 20 per cent 150-test kerosene is not deleterious 

 to the insecticidal value of the arsenite or the fungicidal value of the Bordeaux 

 mixture, but the same strength of crude petroleum can not be recommended for 

 use when spraying for the codling moth. 



(7) A benefit of from 25 to 75 per cent is derived from spraying as regards the 

 amount of fruit dropped, varying with the season and spray. 



(8) The benefit derived from spraying increases in direct ratio as the per cent 

 of dropped fruit and the percent of wormy fruit on unsprayed trees. (Thus with 

 56 and 60 per cent wormy fruit and 69 and 56 per cent dropped in 1902 and 1901, 

 respectively, on Winesaps, there was 112 to 186 per cent benefit to the perfect 

 picked fruit sprayed with disparene; 70 and 87 per cent with arsenites of soda and 

 lime in 1902, and 120 per cent with Paris green in 1901; while with an average of 

 25 per cent wormy dropped on Stark and Nero in 1902 there was but 30 to 37 per 

 cent benefit to perfect picked fruit. ) 



(9) In the same orchard and variety the per cent of perfect fruit dropping is 

 practically the same whether sprayed or unsprayed, the amount of dropped fruit 

 depending upon the percentage of droppings wormy. 



(10) The benefit derived from the spraying lies in increasing the amount of 

 picked fruit and decreasing the amount of wormy droppings, and only partly in 

 decreasing the percentage of wormy picked fruit. 



Mr. Piper suggested that all the fruit that dropped must not be 

 considered as loss, because in many seasons the fruit on the trees 

 should be thinned in order to produce a large and perfect crop. 



Mr. Cooley agreed with Mr. Piper on this point and stated further 

 that in Montana the problem for cou trolling the codling moth was to 



