PflOPCRTY 



BULLETIN .OF: /THE 



No. 189 



Contribution from the Bureau of Entomology, L. O. Howard, Chief 

 April 12, 1915. 



CRN) 



STUDIES OF THE CODLING MOTH IN THE CENTRAL 

 APPALACHIAN REGION. 



By F. E. BROOKS and E. B. BLAKESLEE, 

 Entomological Assistants, Deciduous Fruit Insect Investigations, Bureau of Entomology . 



CONTENTS. 



Page. 



Introduction 1 



Localities in which investigations were made . 2 



Nature and extent of the investigations 2 



Explanation of the use of terms 3 



Investigations at Charlottesville, Va 4 



Investigations at Greenwood, Va 11 



Investigations at Hagerstown, Md 13 



Investigations at Winchester, Va 21 



Investigations at Fishersville, Va 28 



Investigations at French Creek, W. Va 32 



Investigations at Pickens, W. Va 37 



Resume of rearing experiments in Maryland, 



Virginia, and West Virginia 40 



Page. 

 Number of first-brood larvae transforming 



first season 42 



Effect of differences in altitude and latitude 



upon the development of the codling moth. 

 Relative numbers of larvae ascending and 



descending the trees 



Seasonal effect of weather conditions on the 



different stages of the codling moth 45 



Cannibalism among codling-moth larvae 45 



Natural enemies 46 



Summary 48 



42 



44 



INTRODUCTION. 



In many localities throughout the central Appalachian region the 

 recent rapid development of the apple-growing industry has made 

 the control of the codling moth (Carpocapsa pomonella L.) a subject 

 of special and increasing interest. The hilly or mountainous nature 

 of the land has led to the location of orchards at elevations ranging 

 from a few hundred feet to more than 4,000 feet above the level of 

 the sea. The great diversity of temperature that occurs between the 

 lower and the more elevated orchards has a marked effect on the 

 tune of transformation of the different stages of the codling moth, 

 and consequently has direct bearing on the relative number and the 

 destructiveness of second-brood larvse. 



In the spring of 1911 the Bureau of Entomology began a study of 

 the codling moth in the region just mentioned, as a part of its inves- 



