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



braska. The moths measure about 1 inch in wing spread. The base 

 of the front wings is dark gray and the outer third reddish orange. 

 The larvae, when full grown, are nearly three-fourths of an inch long 

 and reddish. There is but one generation annually. The moths fly 

 in April and May in most localities, but in the latter part of May 

 and early in June in the Black Hills. The full-grown larvae leave 

 the tips during July and spin cocoons, usually in the bark crevices on 

 the base of the tree below the litter. Here they transform to pupae 

 and pass the remainder of the season and the winter. Infested tips 

 can be identified, after the larvae leave, by the dead, partially cle- 

 veloped needles toward the apex of the shoot, and by the fact that this 

 part of the shoot, and usualh^ the buds, have been riddled by the 

 larval burrows and crumble readily when dry. 



Rhyacionia fasadenona Kearf. is a silver-gTay moth with reddish 

 markings and a wing spread of five-eighths of an inch. In the 

 caterpillar stage it bores through the buds and twigs of Monterey 

 pine, ponderosa pine, and probalDly other pines in California, causing 

 a pitchy exudation and the deformation or death of the terminal 

 growth. It has recently been found attacking ponderosa pine seed- 

 lings and saplings up to 6 feet in height, where these are growing in 

 o])en stands unshaded by mature trees, on cut-over lands in eastern 

 California. 



RliyaeJoma monfana Busck does similar injury to the buds and 

 twigs of lodgepole pine in Idaho and Montana. 



Pitch Nodltle Moths 



The pitch nodule moths belonging to the genus Petrova {Evetria). 

 while in the caterpillar stage, bore into both the new and old growth 

 of pine stems, twigs, and branches. Their work is characterized by a 

 nodule or round dirty lump of pitch and frass which is formed at the 

 point of attack. They do not attack the buds but usually work at 

 nodes or whorls of branches, and finall}^ pupate within the pitch 

 nodule. Trees are seldom, if ever, girdlecl b}" the larval channels but 

 often are so badly weakened that the tops are broken by wind or 

 snow. The moths are speckled with brown, yellow, or gray mark- 

 ings and have a wing expanse of about three-fourths of an inch. 

 The following species are found in the Western States: 



Species of Petrova Hosts and distribution 



P. })iefallica Busck (fig. 17) Lodgepole and ponderosa pine. California 



to Montana. 



P. sahi)iin)ia Kearf Digger pine. California. 



P. monophylUana Kearf Singleleaf pinon pine. California. 



P. luculentana Hein Ponderosa pine. Colorado. 



P. hurkeana Kearf Sitka and Engelmann spruce. Washington 



and Montana. 



P. picicolana Dyar WMte fir and alpine fir. Washington. 



P. aJbicapitana Busck Lodgepole and ponderosa pine. Idaho and 



Montana. 



PixE Pitch ]Moths 



The caterpillars of the pine pitch moths, belonging to the genus 

 Eucosinoj (39), bore through the pith of terminal shoots and leaders 

 ancl cones of various coniferous trees. Owing to the drooping of the 



