38 MISC. PUBLICATION 273, U. 8S. DEPT. OF AGRICULTURE 
PircH MotTHs 
While in the caterpillar stage the pitch moths, belonging to the 
genus Dioryctria, bore into the cambium of trunk, branches, and 
twigs or into the fresh green cones of pines, Douglas fir, balsam fir, 
and spruce. ‘The entrance to the tunnel is usually indicated by 
webbed. larval castings. If the tree offers resistance to attack a co- 
pious flow of pitch forms a resinous mass at the entrance. The 
damage results in serious injury or death of the parts affected or 
even death of the entire tree. 
The ponderosa pitch moth (Dioryctria ponderosae Dyar) causes 
considerable injury in the plantations of the Nebraska National For- 
est, where it attacks ponderosa, Scotch, Austrian, jack, and Norway 
or red pines. Most of the tr ees attacked are under 8 inches in diam- 
eter, and the bole and tops are frequently girdled by the larval tun- 
nels. This damage is particularly serious in the case of the two 
European species, “Scotch and Austrian pines. This insect is prob- 
ably distributed through most of the Western States, having been 
recorded from Nebraska. Montana, and northern California. 
The adults are blackish- -gray moths with a wing expanse of 
nearly 114 inches. There are two narrow W-shaped bands extending 
across each forewing; the hind wings are dusky white. The moths 
appear from late in July to early in September and deposit eggs 
singly on the under side of bark scales, on trunk, or branches. The 
small larvae hatch in from 1 to 4 w eeks, depending upon the tem- 
perature, and spin small hibernacula under bark scales, in which 
they overwinter. The first evidence of attack appears the following 
spring in the form of a small quantity of larval castings on the 
bark surface, followed by an exudation of pitch from the entrance 
hole. The larvae feed in the cambium region and construct irregu- 
larly shaped galleries beneath the bark. Some of these are rounded 
cavities with short side galleries, while others extend for several 
inches around the tree. The mature larvae are about 1 inch in length, 
usually hght brown, though occasionally with a greenish tinge, and 
the bodies are marked with about six rows of small, dark-brown dots 
or tubercles. These larvae spin white papery cocoons in the burrows, 
or sometimes in the dried pitch mass near the surface, in which 
pupation takes place in July. The new adults leave the pupal skins 
in the cocoons and force their way through exit holes previously pre- 
pared by the larvae but concealed by flakes of bark or small’ webs. 
Control has been attempted by spraying the infested part of the stems 
with orthodichlorobenzene, diluted 1 to 5 with water, to which a 
small quantity of soap and linseed oil was added. The results were 
only partially satisfactory. Winter cutting and removal of the 
most heavily infested trees in the plantations resulted in a consider- 
able reduction in the infestation. Control measures, however, are 
still in the experimental stage. 
Dioryctria xanthaenobares Dyar is a golden-brown moth about 
three-fourths of an inch in length, which in the caterpillar stage at- 
tacks the twigs and cones of ponderosa and knobcone pines and pos- 
sibly other pines. The caterpillar is pinkish and about 1 inch in 
length when full grown. It is known in California, Oregon, and 
Washington. 
