UNITED STATES DEPARTMENT OF AGRICULTURE 
Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief 
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. Srmeier, Entomologist, and H. K. PLanx,? Scientific Assistant, Fruit Insect 
Investigations, in cooperation with the Colorado Agricultural Experiment Station. 
CONTENTS. 
Page. Page. 
The Grand Valley of Colorado............... 2 | Suggestions for the control of the codling 
Comparison of the climatic conditions of moth in the Grand Valley of Colorado.... 30 
Grand Junction, Colo., and Rochester, Avoid presence of spray residue on har- 
INFENS Sae ERR CERES daadee hoe 2 ViESLOG LUTE SMa ye Guiana Sse Pa 33 
Spraying experiments in the Grand Valley... 3 Sprayamatenialsi: tase saws ets an eee eens 34 
Spraying experimentsin 1915............ ee Da! Sprayine equipment#s:.2e eee cass ses a 34 
Spraying experiments in 1916............ 7 | Supplemental controlmeasures.............- 35 
Spraying experimentsin 1917............ 11 BANGIN ees craee ca cake aia as Sia aaa 35 
Spraying experimentsin 1918............ 25 Codling-mothitrapi sso. sccsass ceeumeeee 35 
UMM Ay, OLLESUMS EAs sesso eer sei e sais 29 
SSS Ss 
Owing to the great abundance and destructiveness of the codling 
moth (Laspeyresia pomonella L.) in the Grand Valley 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 history and control. 
The biological study was concluded the following year, 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 ecodling moth 
in the Grand Valley. 
1Jn 1915 and 1916 the senior author was in immediate charge, assisted by E. R. Van Leeuwen, of the 
Bureau of Entomology, during the former season 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. Antles, 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, Bureau of Entomology, and Dr.C. P. 
Gillette, George {. List, and Claude Wakeland, 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 Valley fruit growers. 
2 Resigned June 30, 1920. 
47056°—21— Bull. 9591 
