138 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
The genus Pineus includes four species that may be encountered on 
conifers in the Eastern States. The pine leaf aphid (Pineus pini- 
foliae (Fitch) ) is one of the most important and may infest any of the 
following trees: Eastern white pine, western white pine, lodgepole 
pine, and red, Engelmann, black, and Sitka spruces. It occurs from 
southern Canada and New England west to Montana and Idaho, and 
south to North Carolina and Tennessee. 
The pine leaf aphid overwinters as nymphs on white pine. In the 
spring the nymphs molt into winged individuals and migrate to spruce. 
Feeding on spruce, they pr oduce terminal compact galls that have the 
appearance of true cones and bear in each chamber a single aphid. In 
Maine these galls open about the middle of June, and the nymphs 
emerge, molt, and migrate to the needles of the old growth of white 
pine. There they attach themselves, with their heads pointing toward 
the base of the needles. In this position the females give birth to a new 
generation of nymphs, which migrate to the new growth, feed, become 
covered with a white flocculence, and pass the winter. 
Heavy overwintering populations on pine may cause the needles to 
turn yellow and the new growth to appear sickly. On ornamental 
spruce, galis sometimes become so numerous as to require attention. 
The species has been on the increase in Massachusetts, and heavy in- 
festations have been reported in spruce stands in that State and in 
northwestern Connecticut. 
The pine bark aphid (Pineuws strobi (Htg.)), accidentally intro- 
duced from Europe, is a small dark aphid, covered with flocculent 
wax, that frequently covers the trunk and branches or appears in 
small clusters at the bases of needles on white pine. Hosts of this 
aphid are white, Scotch, and Austrian pines. It is found over most 
of the United States wherever these trees grow. 
Trees in parks and picnic areas, ornamentals, and small nursery 
stock may be seriously affected by heavy infestations of Pineus str ob? : 
however. serious injury seldom results from such infestations on large 
forest trees. Large trees heavily infested appear to have been white- 
washed. Such infestations may be controlled by applying a forceful 
stream of water to them. On small pines a contact insecticide should 
be used. 
Two other species of Pineus are P. floccus (Patch), a pest of spruce 
and white pine; and P. similis (Gillette). which attacks spruce alone. 
P. floccus produces terminal oat on spruce which comprise the entire 
hew growth and cause a thickening of needle bases. The distal part 
of the needle may retain its green ‘color, although the gall itself may 
be purplish. P. similis pr oduces loose terminal galls on the current 
year’s growth of spruce. It may be encountered anywhere from New 
England west to Minnesota. Patch (335, 336), published on her 
studies of these insects. Neither of these species is of much 
importance. 7 
SUBFAMILY PHYLLOXNERINAE 
In this subfamily there are two genera, Phyl/overa and Phylloxer- 
ina.. Most of the species encountered in our forests are found on 
hickory, and none of them appear to be important economically. 
Species of Phylloxerina are sometimes found on willow, poplar, and 
tupelo. 
