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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



Their feeling of great discouragement produced by the conditions in 

 1913 has changed to a hopeful and confident assurance that the prob- 

 lem has been solved. 



In some field experiments which cannot be detailed here we were 

 unable to control the leaf-roller to any degree of satisfaction by omit- 

 ting the application of oils. 



Finally, in our treatment of hundreds of apple, pear, plum, and 

 cherry trees not a single case of injury has been found from the effects 

 of the oils. In addition, many barrels of oil were applied last spring 

 throughout western New York and so far as we have personally exam- 

 ined the treated orchards or have been able to talk with the owners of 

 treated orchards we have not found any injury. It should be noted, 

 however, that the oils were applied in the spring and only after the 

 trees had become more or less active or very near the time of the 

 beginning of activity. Moreover, we were afraid of the oils and con- 

 stantly warned the owner in his general orchard spraying to be careful 

 and not drench the trees. Had the oils been applied more liberally 

 and had the trees been more thoroughly drenched, probably a higher 

 per cent of eggs would have been killed. The owner declares that 

 next year he is going to apply the oils at the rate of 1-12 and that he 

 is going to soak his trees. We have assured him that he will do so on 

 his own responsibility. Undoubtedly Dr. Felt has given us abundant 

 proof that these oils do, under certain conditions, produce an injurious 

 effect. Unfortunately, we do not know just what those conditions are. 



To sum up then, our experiments seem to show that the leaf-roller 

 can be satisfactorily controlled by an application of miscible oil to 

 destroy the eggs, supplemented by thorough sprayings with arsenate 

 of lead. 



Mr. E. p. Felt: I am very glad to have this data, and partic- 

 ularly that in relation to the miscible oils, because the results as noted 

 by Professor Herrick agree quite closely with what I think those oils 

 will do when we make careful application. 



Mr. W. W. Yothers: This subject has been quite thoroughly 

 worked out in Florida during the past five years. The results in Flor- 

 ida show that, the injury which follows the use of several miscible oils 

 can be attributed to the chemicals which these insecticides contain 

 and not to the oil itself. Dr. A. W. Morrill found that Orchard brand 

 was very injurious to citrus trees. The present investigation experi- 

 mented with this insecticide extensively and found independently 

 that it was exceedingly injurious and that it could not be used on cit- 

 rus at any time of the year. The Bureau of Chemistry analyzed this 



