UNITED STATES DEPARTMENT OF AGRICULTURE 



m BULLETIN No. 959 ( 



•^^^'u-t. 



Contribution from the Bureau of Entomology 

 L. O. HOWARD, Chief 



S^f^^^U 



Washington, D.C. 



PROFESSIONAL PAPER 



October 8, 1921 



EXPERIMENTS AND SUGGESTIONS FOR THE CON- 

 TROL OF THE CODLING MOTH IN THE GRAND 

 VALLEY OF COLORADO.' 



By E. H. SiEGLER, Entomologist, and H. K. Plank, ^ Scientific Assistant, Fruit Insect 

 Investigations, in cooperation with the Colorado Agricultural Experiment Station. 



CONTENTS. 



The Grand Valley of Colorado 2 



Comparison of the climatic conditions of 

 Grand Junction, Colo., and Rochester, 



N. Y 2 



Spraying experiments in the Grand Valley. . 3 



SprajTJig experiments in 1915 4 



Spraying experiments in 1916 7 



Spraying experiments in 1917 11 



Spraying experiments in 1918 25 



Summary of results 29 



Suggestions for the control of the codling 



moth in the Grand VaUey of Colorado 30 



Avoid presence of spray residue on har- 

 vested fruit , 33 



Spray materials 34 



. Sprajring equipment 34 



Supplemental control measures 35 



Banding 35 



Codling-moth trap 35 



Owing to the great abundance and destructiveness of the codling 

 moth (Laspeyresia pomonella L.) in the Grand Valle3" of Colorado, 

 the Bureau of Entomology of the United States Department of Agri- 

 culture, in cooperation with the Colorado Agricultural Experiment 

 Station, undertook in 1915 a study of its life historj" and control. 

 The biological study was concluded the following 3^ear, but the control 

 investigations continued during 1916, 1917, and 1918. 



In this report are given the more important results of the spraying 

 experiments and some suggestions for the control of the codling moth 

 in the Grand Valley. 



1 In 1915 and 1916 the senior author was in immediate charge, assisted by E. R. Van I-eeuwen, of the 

 Bureau of Entomology, dining the former sca^son and by H. K. Plank, also of the bureau, during the 

 latter. In 1917 Mr. Plank had charge of the project, assisted by Leo. C. jVntles, of the Colorado Agricul- 

 tural Experiment Station, and during the following year Mr. Antles carried out the experiments under 

 the general direction of Mr. Plank and the Colorado Experiment Station. 



Dr. A. L. Quaintance, in charge of fruit insect investigations, Biueau of Entomology, and Dr. C. P. 

 Gillette, George M. List, and Claud^Wakelaud, of the Colorado Agricultural Experiment Station, made 

 many helpful suggestions throughout the course of the work. The writers also wish to express their 

 appreciation for the cooperation of the Grand VaUey fruit growers. 



2 Resigned Jime 30, 1920. 



47056°— 21— Bull. 959 1 



