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



to be the preferred host, but true fir and spruce foliage is also 

 eaten. 



BUDMOTHS, BUDWORMS, AND LEAF ROLLERS 



One group of moths, belonging largely to the family Tortricidae, 

 lay their eggs on the needles of coniferous trees or the leaves of 

 various broadleaved trees, and the young caterpillars feed on the 

 opening buds and new leaves or needles, drawing these together 

 with a silken web. Later, as they become larger, they may leave 

 their protective web and feed openly on the leaves or older needles 

 and if numerous will completely defoliate the tree. When growth 

 is completed the larvae transform to the pupal stage, usually in 

 small webs spun about the dead foliage at the tips of the branches, 

 and from these the adult moths emerge. 



Under normal conditions the damage consists only of a few dead 

 tips or partly eaten leaves. When buds are killed, subsequent 

 branching results at these points, but seldom is the life of the tree 

 threatened. When epidemic outbreaks occur, large forest areas 

 may be completely defoliated and killed. 



The spruce budworm (Choristoneura fumiferana (Clem.)) (62, 

 6Jf, 125, 158) (fig. 43), is one of the most destructive defoliators 

 in this group. It is widely distributed through the fir forests of 

 Canada, the Northeast, the Lake States, the Rocky Mountain re- 



FlGURE 43.— The spruce budworm (Choristoneura fumiferana) : A, Eggs on 

 under side of fir needle; B, half-grown caterpillar; C, full-grown cater- 

 pillars; D, pupae; E, fir twig with pupa attached; F, defoliated fir twig 

 with empty pupal cases; G, adult moths. All natural size. (Evenden.) 



