84 



MISC. PUBLICATION 273, U. S. DEPT. OF AGRICULTURE 



During the latter part of August the mature caterpillar, which is 

 dark green and about one-half inch in length, drops to the ground on 

 a silken thread and, after crawling into the mat of old needles, 

 spins a loosely woven cocoon in which the winter is passed in the 



pupal stage. The 

 a d u 1 1 emerges the 

 following May or 

 June, completing one 

 single annual gener- 

 ation. The work of 

 the loclgepole pine 

 needle tier is recog- 

 nized b y t h e silk- 

 lined tubes, that may 

 consist of as many 

 as 16 needles Avebbed 

 together, and which, 

 as a result of the 

 feeding, turn brown 

 and die. 



A related species, 

 Argyrotaen ia citrana 

 Fern., feeds on the 

 needles of Monterey 

 pine in California. 



The spruce bud- 

 m o t h [Zeiraphera 

 ratzeh urgian a Katz. ) 

 is an introduced pest 

 that has become 

 established in the 

 P a c i fi c Xorthwest. 

 The small, light - 

 brown moths, with 

 darker diagonal 

 m a r k i n g s, and a 

 wing expanse of 

 about one-half inch, 

 lay their eggs on 

 spruce needles. Each 

 y o u n g caterpillar 

 cravrls into an open- 

 ing bud and feeds on 

 the tender new 

 needles, webbing 

 them together to 

 form a shelter within which it feeds. Growth is completed late in the 

 summer, and the chrysalicl is formed in the shelter at the tip of the 

 infested twig. The adults emerge late in the summer. There 

 appears to be one generation a year. The damage has been fre- 

 quently noted on young Sitka spruce trees along the coast of Oregon 

 and Washington. In many cases all of the new tips are killed and 

 the tree made to branch excessiyelj^ 



Figure 41. — The lodgepole pine needle tier [Aicjyrotaenia 

 pinatubana) : A, Webbed foliage; B, a silk-lined needle 

 tube ; C, full-grown larvae, X 2. 



