526 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



complete and covers its behavior diirinfi^ tlie entire year. A complete 

 report on tlio investigations in the field and laboratory during the 

 past three years is now in course of preparation. 



THE CODLING MOTH. 



Studies of the codling moth on apple have been continued along 

 lines previously reported. The experiments undertaken in the spring 

 of 1900 in a comparison of the so-called one-spray method, in use 

 in the Northwest, wdth the practice of spraying generally followed 

 in the Ea.~t, were concluded and a large amount of data on the subject 

 accumulated, the results of which have already been submitted for 

 publication. In general, it appears that about as good results may be 

 obtained by the one-spray method, in so far as the control of the cod- 

 ling moth and curculio is concerned, as by several treatments applied 

 in the customary way. Notwithstanding these results obtained by the 

 one-spray method, however, the plan is not considered to be of special 

 importance under eastern conditions, for the reason that in this terri- 

 tory it is necessary in nearly all cases to make several applications of 

 a fungicide during the course of the season for the control of fungous 

 diseases, and under these circumstances the addition of an arsenical 

 is, of course, desirable. However, the Avork points out unmistakably 

 the great importance of much more thorough spraying at the time 

 of the falling of the petals and under a higher pressure than has 

 generally been given heretofore. Further tests of the one-spray 

 method are in progress in Virginia and Michigan, and it is hoped 

 that a final report may be prepared at the close of the present season 

 from the data secured. 



The experiments in Missouri and Arkansas orchards in cooperation 

 wdth the Bureau of Plant Industry of this Department, and men- 

 tioned in the last report, comprising a comparison of dusting versus 

 spraying in the control of the codling moth, plum curculio, and 

 fungous diseases, w^ere concluded in the fall of 1909, and report 

 upon the work is in preparation. It appears that the use of dust 

 sprays for the codling moth, curculio, and other apple insects gave 

 results very much inferior to those obtained by the use of liquid 

 sprays, and the dust sprays are notably ineffective in the control of 

 fungous diseases. Thus, in Missouri the yield of merchantable fruit 

 from dusted plats was approximately 3 per cent of the crop as com- 

 pared with 8G per cent of merchantable fruit on plats sprayed with 

 Bordeaux mixture and arsenate of lead. 



Life-history studies of the codling moth in important fruit regions 

 are being continued as heretofore, as in California and Michigan. 

 The studies in progress during the last two seasons in northwestern 

 Pennsylvania have been completed and a report upon the work is 

 now in press. This investigation brought out forcibly the influence 

 of temperature on the extent of, and injury by, the larvae of the 

 second brood. Thus, during the season of 1907 the proportion of 

 first-brood larvre to transform into adults was 3 per cent, whereas 

 during the season of 1908 the proportion transforming was 67.7 per 

 cent, a difference due entirely, it is believed, to the widely different 

 seasons which prevailed during these respective years. Similar 

 studies have been made in the Ignacio Valley, in California, in con- 

 nection with experiments for the control of the codling moth on 



