U.S. D. A., B. E. Bul..97, Part IV. D. F. I. I., October 17, 1911. 
PAPERS ON DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 
THE CALIFORNIA PEACH BORER.' 
(Sanninoidea opalescens Hy. Edw.) 
By Dupitey Movutton, 
Formerly Special Agent, Deciduous Fruit Insect Investigations. 
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 treesand 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. VIII.) 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. be 
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