118 Agricultural Experiment Station, Ithaca, N. Y. 



use upon trees which are being treated for fungi, to determine the 

 comparative value of different materials, is not advisable. London 

 purple was this year applied to one-half of a Fall Pippin tree to 

 discover if the scab would be affected by the applications. Five 

 treatments were made. This variety of apple is generally very 

 much injured by scab, but it may also be protected quite easily by 

 the use of proper fungicides. Some trees to which the Bordeaux 

 mixture had been applied produced very large and fair fruit. But 

 those treated with London purple showed absolutely no benefit 

 from the application, neither upon the foliage nor upon the fruit. 

 The poison contained nearly seventy-five per cent, of the normal 

 arsenite of calcium, and had been used with success against the 

 codlin moth in previous years. 



The value of former applications of ar seniles. — 15 o treatments 

 were made this year that were connected with the destruction of 

 the codlin moth. During the past two years the orchard had been 

 so thoroughly sprayed with arsenites that it was supposed these 

 applications might have had considerable influence in the extermi- 

 nation of the pest. There is no large apple orchard near the one 

 treated. And this comparative isolation, it was hoped, would not 

 be without its influence. But as the season advanced the conse- 

 quences of this neglect became more apparent. Not only did the 

 codlin moth flourish, but also nearly every insect that could in any 

 way disfigure an apple. The curculio was very prevalent, and 

 assisted in the disfigurement of nearly every apple in the orchard. 

 The light crop appeared to compel the insects to concentrate their 

 •efforts upon the few apples that were borne, and rarely has a crop 

 of apples shown more clearly the extent to which insects alone can 

 ruin fruit. The average amount of injury obtained from several 

 trees of different varieties, treated and untreated, showed that 76 

 per cent, of the fruit had been attacked by the codlin moth ; the 

 lowest figure obtained was TO, from a tree thoroughly sprayed with 

 the Bordeaux mixture, and the highest 80, produced by an unsprayed 

 tree. If other insect injuries had been considered, the per cent, 

 would undoubtedly have been nearly 100. 



Doubt is sometimes expressed as to the comparative seriousness 

 of the apple scab and the codlin moth. It is probable that if the 

 insects had been controlled in the orchard instead of the fungi, the 

 injury done would have been less. And this leads us to the question 

 •of the comparative value of all applications. In apple orchards I 



