CONTKOL OF CODLING MOTH IN COLORADO. 3 



Table 1. — Comparison of mean normal temperature and precipitation, Grand Junction, 



Colo., and Rochester, N. Y. 



Month. 



May 



June 



July 



Ausrust 



September 



Average or total 



Grand Junction, 

 Colo. 



Mean 

 normal 

 temper- 

 ature. 



F. 



58.9 

 72.6 

 79.2 

 76.1 

 66.4 



70.6 



Mean 

 normal 

 precipi- 

 tation. 



Inches. 

 0.92 

 0.40 

 0.50 

 1.04 

 0.95 



3.81 



Rochester, N. Y. 



Mean 



^^ean 



normal 



normal 



temper- 



precipi- 



ature. 



tation. 



"" F. 



Inches. 



.56.7 



2.94 



65.9 



3.13 



70.4 



3.09 



6S.3 



2.96 



01.9 



2.32 



In the course of the life-history investigations in the Grand Valley 

 it was found that a female moth deposited as many as 316 eggs and 

 that several laid over 300 eggs each.^ In other localities where the 

 Bureau of Entomology has conducted similar investigations, the 

 fecundity of the female moth has never been found to be so high. 

 The nearest approach to the individual egg production in the Grand 

 Valley was found in the Pecos Valley of New Mexico, where like 

 climatic conditions obtain and where one female moth was recorded 

 to have produced 259 eggs." In the fruit belt of western Michigan, 

 where the weather conditions approximate those of western New 

 York, the most eggs laid by a moth, according to the records of 

 A. G. Hammar, was 161.' 



It has been quite generally established that semiarid climatic 

 conditions are very favorable to the development of the codling moth, 

 whereas humid conditions and lower temperatures retard its develop- 

 ment. 



SPRAYING EXPERIMENTS IN THE GRAND VALLEY. 



Spraying experiments were conducted in several orchards during 

 the seasons of 1915, 1916, 1917, and 1918, on representative apple 

 varieties. The results herewith presented, however, arc confined to the 

 Ben Davis and Gano, since the Grand Valley fruit growers generally 

 experienced more difficulty in controlling the codling moth on these 

 than on any other conmiercial varieties. 



In the spraying experiments described an attempt was made to 

 time the spray applications according to the development of the 

 codling moth as indicated by the life-history studies and field obser- 



6 Sioglcr, E. H., and Plank, H. K. The Life History of the Codling Moth in the Grand Valley of Colo- 

 rado. U. S. Dept. Agr. Bui. 932. 1921. 



8 Quaintance, A. L., and Geyer, E. W. Life History of the Codling Moth in the Pecos Willey, New 

 Mexico. U. S. Dept. Agr. Bui. 429. 1917. 



' Hammar, A. G. Life History Studies on the Codluig Moth in Michigan. U. S. Dept. Agr. Bur. Ent. 

 Bui. 115, Pt. 1. 1912. 



