UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 932 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



September 20, 1921 



LIFE HISTORY OF THE CODLING MOTH 



IN THE GRAND VALLEY OF 



COLORADO 



By 



B? H. SIEGL,ER, Entomologist, and H. K. PLANK, Scientific 

 Assistant, Fruit Insect Investigations, in Coopera- 

 tion with The Colorado Agricultural 

 Experiment Station 



CONTENTS 



Introduction 



The Grand Valley of Colorado 

 Explanation of Terms . . 



Methods and Rearing Apparatus Era 

 ployed in the Life-History Studies 



The Insectary 



Seasonal-History Studies of 1915 



Wintering Larvae . . . 



Pupae of the Spring Brood . 



Moths of the Spring Brood . 



The First Generation . . 



The Second Generation 



The Third Generation 

 Codling-Moth Band Studies of 1915 

 Seasonal-History Studies of 1916 



Pupae of the Spring Brood 



Moths of the Spring Brood 



The First Generation 



The Second Generation 



The Third Generation 

 Codling-Moth Band Studies of 1916 . 

 Natural Enemies of the Codling Moth . 

 Miscellaneous Studies . ..... 



Effect of Cool Temperatures on 

 Emergence of Moths of the Spring 

 Brood 



Miscellaneous Studies — Continued 



Time of Day Moths Emerge ... 84 



Codling Moth Flight Trials .... 87 



Time of Copulation .... 89 



Time of Day Moths Oviposit ... 91 



Oviposition by Individual Moths . . 99 



Deposition of Infertile Eggs .... 106 

 Time Required for Codling Moth 



Larva to Leave the Egg . • • 107 

 Larvae that Fail to Extircate Them- 

 selves From the Chorion .... 107 

 Habits of Newly Hatched Larvae . . 108 

 The Codling Moth "Sting" . . . . 108 

 Codling Moth Larvae Feeding on Pear 



Twigs 108 



Experiments with Black and White 



Bands 109 



Percentage of Transforming and 



Wintering Larvae Ill 



Laspeyresia pomonella (L.) var. 



simpsonii (Busck) Ill 



Review of Seasonal -History Studies of the 



Codling Moth in 1915 and 1916 ... 112 



Summary 115 



JP*&*^&U 



WASHINGTON 

 GOVERNMENT PRINTING OFFICE 



1921 



