UNITED STATES DEPARTMENT OF AGRICULTURE 



Utb BULLETIN No. 932 jWfe 



Ai&v Contribution from the Bureau of Entomnloffv •5Sk.lk>i>iM^? 



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Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



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Washington, D. C. 



PROFESSIONAL PAPER 



September 20, 1921 



LIFE HISTORY OF THE CODLING MOTH IN THE 

 GRAND VALLEY OF COLORADO. 



By E. H. Siegleb, Entomologist, and H. K. Plank, Scientific Assistant, Fruit 

 Insect Investigations, in cooperation with The Colorado Agricultural 

 Experiment Station. 



CONTENTS. 



Page. 



Introduction 1 



The Grand Valley of Colorado 2 



Explanation of terms 3 



Methods and rearing apparatus em- 

 ployed in the life-history studies—. 7 



The insectary 8 



Seasonal-history studies of 1915 9 



Wintering larvaa 10 



Pupae of the spring brood 10 



Moths of the spring brood 12 



The first generation 17 



The second generation 



The third generation 



Codling-moth band studies of 1915 



Seasonal-history studies of 1916 



Pup33 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 



31 



40 

 40 

 45 



46 

 48 

 52 

 66 

 75 

 78 

 82 

 83 



S3 



Page. 



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 



Larvse that fail to extricate them- 

 selves from the chorion 107 



Habits of newly hatched larvse_. 108 



The codling moth "sting" 108 



Codling moth larva? feeding on 



pear twigs 108 



Experiments with black and white 



bands 109 



Percentage of transforming and 



wintering larvae 111 



Laspeyresia pomonella (L.) var. 



simpsonii (Busck) 111 



Review of seasonal-history studies of 



the codling moth in 1915 and 1916. 112 



Summary 115 



INTRODUCTION. 



The codling moth, Laspeyresia pomonella (L.) (PL I, A) is 

 generally recognized as the most serious insect pest attacking the 

 fruit of the apple and pear and is particularly abundant and destruc- 

 tive in the Grand Valley of Colorado. As a result of the extensive 

 injury to the fruit industry of this valley for which this insect is re- 

 sponsible, it was deemed desirable to make a thorough study of its 

 life history as a basis for control experiments. 



19552°— 21 1 



