BUREAU OF ENTOMOLOGY. 637 



check on the latter. Comparative studies are in progress on the 

 root galls produced by the insect on varieties of grapes showing 

 varying degiees of resistance to determine if possible the reasons 

 for the comparatively less injury to some sorts than others. 



WOOLLY APPLE APHIS. 



The woolly apple aphis has long been complained of by orchard- 

 ists, but its injuries during recent years have apparently been on 

 the increase. As a result, there have been frequent requests for more 

 effective treatments than those commonly recommended against it. 

 The investigation of this insect already under way has been ma- 

 terially strengthened and includes a thorough life-history study of 

 the insect at the Vienna (Va.) laboratory and tests of a large series 

 of substances likely to possess value in its control, both in nurseries 

 and orchards. 



While nurserymen and orchardists of certain other countries have 

 for many years made use, in their propagation work, of the roots of 

 varieties of apples resistant to the aphis, American nurserymen, 

 with one or two exceptions, have given little if any attention to this 

 subject. There appears to be no question whatever that injuries 

 from this pest to the roots of apple trees may be avoided by the em- 

 ployment of the roots of certain varieties of apple in a w\ay similar 

 to that which is followed in the case of the grape Phylloxera. Es- 

 pecial attention, therefore, is being given to determine the relative 

 degree of resistance to aphis attack of the roots of our principal com- 

 mercial as well as other varieties of apple. A collection of apple 

 grafts and seeds has been planted, and the plants when readj'^ for 

 distribution will be tested as to aphis resistance in different parts of 

 the country. 



THE CODLING MOTH. 



Studies of the codling moth which have been under way during the 

 past several years in different fruit sections representing different 

 climatic conditions are being continued. The life-history studies in 

 progress in Michigan during 1011, as mentioned in a former report, 

 were completed at the close of that year, and a report on the work 

 IS now in press. Also the life-history investigations which have 

 been in progress in the Santa Clara Valley in California have been 

 completed and a full report on the subject has been submitted for 

 publication. The bureau has received considerable complaint from 

 apple growers in portions of New Mexico, and in other southwestern 

 States, of their inability satisfactorily to control the codling moth 

 on apples and pears by the methods found etl'ective in the East. 

 Beginning with the spring of 1912 it was found practicable to estab- 

 lish a laboratory at Roswell, N. Mex., to which is tributary a large 

 fruit-growing interest. Careful attention is there being given to ob- 

 .-ervations on the habits of the codling moth, and lar^e-scale spray- 

 ing experiments are in progress in orchards to determine the proj>er 

 schedule of applications to be followed under the conditions there 

 existing. 



The tests in progress during the fiscal year 1910-11 of the so-called 

 one-spray method in comparison with the usual schedule of treat- 



