U. S. D. A.,B. E. Bui. 97, Part IV. D. F. I. I., October 17. 1011 



PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



THE CALIFORNIA PEACH BORER. 1 



(Sanninoidea opalescens Hy. Edw.) 



By Dudley Moulton, 



Formerly Special Agent. 



INTRODUCTION. 



The California peach borer (Sanninoidea opalescens Hy. Edw. ; fig. 

 22) has been the subject of investigation by the Bureau of Entomology 

 since the summer of 1907. The writer, however, had observed its 

 habits and the various methods used in its control for several years 

 previous to that time and vividly recalls spending many hours in his 

 father's orchard digging " borers" from the trees and later applying 

 the protective washes. As a boy he was taught that this practice 

 was quite as necessary in the general scheme of orchard treatment 

 as was pruning or cultivating. This insect has been a menace to 

 fruit growers in the Santa Clara Valley from the very beginning of 

 the fruit-growing industry and the constant care and the disagreeable 

 labor which accompanies the digging of the borers has led many 

 orchardists to become intimately well acquainted with it in the larval 

 or borer condition. (See PL VTIL) Many men of their own accord 

 have experimented with various methods of control. Orchardists 

 seldom recognize the adult moths and know little about their habits, 

 although they know the larval stage so well. 



The California peach borer derives its common name from its close 

 relationship to the peach borer of the East (Sanninoidea exitiosa Say), 

 and from the fact that it is primarily an enemy of the peach and 

 other closely related plants. Systematically, the species is closely 

 related to the eastern peach borer, and it is difficult to distinguish 

 the two species by comparing the larval stages alone. The female 

 moth of the eastern form, however, is readily distinguished from the 

 moth of the western species by the presence of conspicuous orange 



1 The present paper gives the results of observations on the California peach borer made by Mr. Moulton 

 while engaged in deciduous fruit insect investigations in the Bureau of Entomology and located at San 

 Jose, Cal. 



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