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UNITED STATES DEPARTMENT OF AGRICULjm& 
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bulletin/;njo..^95 •; 
Contribution from the Bureau of Enrtfmojogy ' ' -• V 
L. O. HOWARD, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 
October 28, 1915 
THE ZIMMERMAN PINE MOTH. 1 
By Josef Brtjnner, Assistant in Forest Entomology, Forest Insect Investigations. 
Description of the insect 
Seasonal history and habits. 
Relation to other insects 
Relation to natural enemies. 
Habitat and hoSt trees 
CONTENTS. 
Page. 
Page. 
2 Character of injury and work of larvae 8 
3 Effect of infestation on tree growth and forest. 9 
5 Remedy 10 
6 Conclusion 11 
7 Literature cited 12 
INTRODUCTION. 
One of the insects of the order Lepidoptera very destructive to 
coniferous trees, and especially to yellow pine (Pinus ponderosa) in 
various sections of the West and, according to Zimmerman, Grote, 
-and Kellicott, to white pine (Pinus strobus), Canadian or red pine (P. 
resinosa), Austrian pine (P. austriaca), Scotch pine (P. sylvestris), 
Swiss pine (P. cembra), and other pines in the East, is the Zimmerman 
pine moth (Pinipestis zimmermani Grote 2 ). Aside from being 
largely the cause of "spike-top " (PL I) in mature timber, it spike-tops, 
stunts, and kills outright innumerable trees of the so-called "second 
growth." The timber of at least one area, thus far discovered, has 
been brought into such ill repute that carpenters and builders refuse 
to use it for anything in which "never-ending shrinkage" is objec- 
tionable. 
Having noted during several seasons the severe injuries inflicted by 
the larvge of this insect, the writer, at the suggestion of Dr. A. D. Hop- 
kins, undertook, during the autumn of 1912, a systematic study of its 
seasonal history and habits, the recorded information on this insect 
being inadequate. • This study was conducted during 1913-14 in 
conjunction with other work on insects which affect reproduction and 
Pinipestis zimmermani Grote. 
2 Identification by August Busck. 
Note.— This bulletin is of special interest to manufacturers and users of pine lumber from the Western 
States. 
4249=— Bull. 295—15 
