Vol. 1, Wo. 5.] INSECT LIFE. [November, 188§. 



SPECIAL NOTES. 



Prof. A. J. Cook's latest bulletin * is devoted to a consideration of 

 experiments with insecticides and implements for their application. 

 The larger portion of the bulletin refers to the treatment of apple 

 trees for Codling Moth and plum and cherry trees for Plum Curculio. 

 Professor Cook designed to show the relative effect on foliage from 

 repeated sprayings with London purple aud also the comparative im- 

 munity from injury of trees so treated. The data on which he con- 

 structs his table are so indistinct that it is difficult to form conclusions 

 concerniug them. We gatlier, however, that where trees were treated 

 once the foliage was uuinjured and few apples were perfected or ripened ; 

 where treated twice, foliage slightly injured and "much fruit" perfected; 

 where treated three times, foliage more injured (sometimes seriously) 

 and "much fruit" perfected. The applications were made on the 6th, 

 12th, and 20th of June. The preparation used was 1 pound London 

 pur])le to 100 gallons of water. The check trees were crab-apples, one 

 of which bore few apples and the other bore heavily. He concluded 

 that " it is more and more patent that it pays remarkably well to spray 

 our apple trees." 



In view of the extensive practical experience of orchardists for many 

 years now with the arsenites as a prj^tection from the Api^le-worm, ad- 

 ditional experimentation is hardly necessary on this point, as the value 

 of this i^reventive method has become fully established, the only ques- 

 tion to be advantageously discussed in connection therewith being the 

 risk of poisoning, which, as exi)erience and Professor Cook's experi- 

 ments in the past have shown, is reduced to a minimum, or may be 

 left out of account altogether where proper precautions are taken. It 

 is otherwise with these arsenites as a preventive for Curculio attack. 

 We have long felt that they might be used with benefit for this purpose, 

 and have recommended their trial, but from the nature of the case we 

 have anticipated less good than in the case of the Apple-worm, and 

 Professor Forbes' experiments and some unpublished experiments which 

 we have had made by Mr. Alwood confirm this view. Several plum and 



* Agricultural College of Michigan, Departmeut of Zoology and Entomology. 

 Bulletin 39. September, 1888. 



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