ENGLISH: ILLINOIS TREES: THEIR INSECT ENEMIES 57 



Control Measure 12 (end of circular) in winter or Control 

 Measure 3 in June after eggs have hatched. 



Pine Bark Aphid, Pineus strobi (Htg.), fig. 41. — White 

 patches of cottony substance on the trunks and limbs of pines 

 make an infestation of this pest easy to recognize. The insect 

 prefers white pine but sometimes feeds on Scotch and Austrian 

 pines. Its feeding does little damage to large, thrifty trees but 

 may weaken young trees. 



The immature aphid, which overwinters under the "cotton," 

 matures in the early spring and lays yellowish eggs, which also 

 are covered with "cotton." These eggs hatch in June, producing 

 both winged and wingless forms. The winged form apparently 

 migrates to other pines. The wingless form remains where it was 

 hatched and lays eggs which produce the overwintering nymphs. 



Control Measure 3 or 8 (end of circular) applied forcefully 

 in June. 



European Pine Shoot Moth, Rhyacionia buoliana (Schiff.). — 

 The black-headed, brown larvae of this species may cause serious 

 damage to Mugho, red, and Scotch pines by boring into the shoots, 

 causing them to turn brown and die. The partly grown, over- 

 wintering larvae become active in the spring and bore into unin- 

 f ested shoots ; pitch forms at the entrance holes they make. Pu- 

 pation occurs in early summer, and the female moth, soon after 

 emerging from her pupa, deposits eggs near the tips of twigs. 

 Each young larva bores into the bases of needles to feed ; feeding 

 by the larva causes the needles to turn yellow. Later the larva 

 bores into a shoot for the winter. 



Control Measure 2 (end of circular). Spray applications 

 must be timed to poison young larvae when they are active in 

 mid-April and late June or early July. Removal and destruction 

 of infested shoots in winter may help control this pest. 



Nantucket Pine Moth, Rhyacionia frustrana (Comst.), fig. 

 42. — The small, yellowish larva of this insect is only about one- 

 half inch long. It may kill many tips of red, jack, and other 

 pines. The adults, reddish-brown moths, emerge in the spring 

 from overwintering pupae. The female deposits flat, yellowish 

 eggs on the needles and terminal leaf buds of pines. The larvae 

 mine the needles at first but later bore down the centers of twigs 

 They construct delicate webs that enclose the affected needles 

 and twigs. Larvae of the first two generations per year pupate 

 in buds. 



