October, lo] CHILDS: CONTROL OF THE APPLE LEAF-ROLLER 457 



Vice-President Cooley: The next paper will be presented by 

 Mr. Leroy Childs. 



SPRAYING NOTES ON THE CONTROL OF THE FRUIT TREE 

 LEAF-ROLLER IN THE HOOD RIVER VALLEY 



By Leroy Childs, Research Assistant, Department of Ento7nology, Oregon Agricul- 

 tural College, Corvallis, Oregon 



In the face of the already valuable information that is available on 

 the hf e-history and the control of the leaf -roller, this paper and the work 

 that it represents might appear to some as superfluous. In citing 

 the literature, however, I find little or no published experimental 

 work dealing with the control of this serious and numerically increas- 

 ing apple pest on the Pacific Coast. A still more important point 

 which made experimentation, at least with the oils, imperative was 

 to determine if possible what influence spring applications of oils 

 have on the adhesive properties of fall applications of Bordeaux 

 mixture. In the Northwest we have a very serious apple disease 

 known as apple tree anthracnose, for control of which Bordeaux 

 is applied before the early rains in the fall. It has been suggested, and 

 seems, indeed, quite possible, that there may exist some such condi- 

 tion, information relative to which is desired before the general use 

 of oil can be recommended. The anthracnose spray has not been 

 applied with the result that a report on this point is impossible at this 

 time. The leaf -roller, however, has passed through its period of activ- 

 ity for this season and the data gathered relative to its control is 

 complete. 



In the Hood River Valley the presence of the apple leaf-roller is 

 not general. The limits of the present infestation are well defined, 

 comprising at the present time some five hundred or six hundred 

 acres. A yearly expansion of these limits occurs and the losses are 

 increasing, with the result that the orchardists are planning a vigorous 

 campaign against the pest next year. 



At no time in Hood River has the infestation occurred to such an ex- 

 tent as to cause noticeable defoliation; occasionally the tender foliage of 

 growing terminals is severely injured but in no place has there occurred 

 the complete defoliation that has been reported in different sections of 

 the East. The injury to the fruit, however, in several orchards where 

 extensive countings were made produced surprising information. The 

 losses incurred by the feeding worms often approached 40 per cent of 

 the entire crop. It was found that the injury was even more severe on 

 trees in light bearing, where the percentage of injury amounted to 



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