U. S. D. A., B. E. Bui. 97, Part II. D. F. I. I., April 1 1911. 



PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



LIFE HISTORY OF THE CODLING MOTH AND ITS CONTROL 



ON PEARS IN CALIFORNIA. 



By S. W. Foster, 

 Agent and Expert. 



INTRODUCTION. 



The codling moth (Carpocapsa pomonella L.) in California presents 

 certain differences in its life history as compared with what is true 

 for the East, principally a lengthening of the respective stages, 

 due to a lower mean temperature during their period of development, 

 especially in the first generation. As remedial measures can only 

 be properly prescribed when based on a complete knowledge of the 

 insect to be controlled, such observations as were possible on the life 

 history of the insect in the vicinity of Walnut Creek were made during 

 the seasons of 1909 and 1910. These, with field notes from other 

 sections during 1910, are given in the following pages. For com- 

 parison, and also to further supplement the writer's own observa- 

 tions, some data from San Jose, Cal., are included, as secured by Mr. 

 F. L. Young, of the Bureau of Entomology, working under the direc- 

 tion of Mr. P. R. Jones. 



The pear crop of California suffers much from injury by the codling 

 moth, and in view of the commercial importance of this crop, the 

 losses represent in the aggregate a large item. The injury is espe- 

 cially important on green fruit destined for shipment to eastern 

 markets, but even in the case of drying stock there is without doubt 

 an important deterioration in quality. The results of experiments 

 reported in this paper show that much may be done to lessen this 

 damage by two or three timely applications of poison sprays, and it 

 is hoped the recommendations may prove of value to California pear 

 growers. 



The writer desires to acknowledge the assistance of Mr. E. J. 

 Hoddy, formerly of this bureau, in helping with part of the spraying 

 experiments and in taking results. Also, to express thanks to 



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