810 JOUENAL OF THE EOYAL HORTICULTURAL SOCIETY. 



EEPORT UPON AN INVESTIGATION OF THE CODLIN MOTH 

 IN IDAHO IN 1900. By C. B. Simpson. 



:Bu1L Xo. 30, N.S., U.S. Dep. Agr. Div. Ent., pp. 51-63.] 



[.4s this Fapcr is likchj to he of rev?/ great service to British fniit- 

 cjroivers, it has been thought desirable to give it in detail. It should be 

 borne in mind, however, that the i)est in question is in Great Britain 

 single-brooded, or rarely double-brooded. The general treatment of the 

 jyest might, nevertheless, icitli due care, effect corresponding results in 

 this country. — B.N.^ 



The follo^Ying report upon an investigation of the codling * moth in the 

 State of Idaho is made in accordance with the authorisation of the Secre- 

 tary of Agriculture and instructions of the Chief of the Division of 

 Entomology. 



Upon reaching Boise I commenced a rigid inspection of orchards in 

 that vicinity and observed the methods used against the codling moth and 

 the results of the same. Numerous cages were started for the study of 

 the life-history of the insect. Many articles upon the insect were 

 ]3ublished in the leading papers. These articles were copied by many of 

 the other papers. I also had a long conference with Professor Aldrich, of 

 the University of Idaho, in regard to the codling moth. 



Extent of Injury. 



Indications of damage caused by the codling moth were seen in every 

 section of the State which I visited where apples are grown. By report 

 the moth is present all over the State, except in a few limited localities in 

 the mountains. From my observation I can say without hesitation that 

 50 per cent, of the apple crop of Idaho was destroyed by the codling moth 

 in 1900. According to Mr. McPhersonthe loss in South Idaho and about 

 Lewiston for the districts was 75 per cent. 



In untreated orchards I found a great difference in the percentage of 

 api)les infested. The injury ranged from 40 per cent, to practically 100 

 per cent. In the small orchards and isolated trees in and about Boise I 

 have been unable to find sound apples. In the larger untreated orchards,, 

 which were more or less isolated, I found in some cases the injury to be 

 about 40 per cent. In orchards well cared for I estimated the injuries to 

 vary from 50 to 0"05 per cent. In an orchard near Boise that was 

 sprayed and banded 44 per cent, of the crop was lost. In an orchard in 

 the city of Boise that was sprayed with arsenites and banded the loss was 

 only about 20 per cent. In more or less isolated orchards that were well 

 cared for the loss was found to be 10 per cent, or less. In another 

 orchard near Boise, which had been sprayed three times and not banded^ 

 the injury was from 90 to 98 per cent. In an orchard that was only 

 banded the injury was about 60 per cent. 



* The word is so spelt in America, but the old English name of the Apple from 

 ^Yhich the moth takes its name Nvas and still is '• Codlin." — Ed. 



