emerge in early fall and deposit their eggs in slits in the round 
face of current season’s needles near the tips of well-exposed 
branches.. The female does not lay her entire complement of eggs 
in the needles of a single twig—sometimes only one needle per 
twig is chosen. There is one generation per year (409). 
Little or no mortality results from a single defoliation because 
only the older needles are eaten, but where defoliation continues 
for several years a high percentage of the affected trees may be 
killed. Overmature trees are particularly susceptible to damage. 
The white-pine sawfly, Neodiprion pinetum (Norton), occurs 
throughout the range of eastern white pine, its preferred host, in 
eastern United States and southern Canada. Pitch, shortleaf, red, 
and mugho pines are also attacked at times. Full-grown larvae are 
pale yellow and about 25 mm. long. The head is black and four 
rows of black spots extend from the head to a black spot at the 
posterior end. 
In the spring, the female deposits her eggs in needles, three to 
four per needle, and the full complement is placed in the needles 
of a single twig. The larvae feed gregariously on both old and 
new needles, and when one branch is defoliated they migrate to 
another. When they reach maturity they drop to the ground and 
spin cocoons in the soil. Winter is spent as a mature larva in a 
cocoon spun in the soil and pupation occurs in the spring. There 
is one, and sometimes a partial second, generation per year, de- 
pending on location. 
The white-pine sawfly attacks trees of all sizes both in planta- 
tions and in forest stands. Because the larvae feed on both old 
and new needles, they are capable of completely defoliating a tree. 
Widespread outbreaks occur occasionally, whereas local ones are 
reported almost every year. 
The balsam-fir sawfly, Neodiprion abietis (Harris), occurs from 
New England to the Lake States and Missouri and from coast to 
coast in southern Canada. Its favored host is balsam fir but it 
also attacks black and white spruces. Full-grown larvae are dark 
green and are from 18 to 25 mm. long. The head is black and the 
body is marked with six longitudinal dark stripes or bands on the 
back, the lowest of which may be broken up into small dots or 
spots. 
Winter is spent in the egg stage and hatching occurs in May or 
June. Newly-hatched larvae feed gregariously on old needles, eat- 
ing only parts of the needle. Feeding is completed in about 1 
month. The mature larvae then spin tough, silvery or light brown 
cocoons on the needles or in the litter on the ground. Adults ap- 
pear from late July to early September and lay their eggs singly 
in slits cut in the edges of the needles. There is one generation 
per year. 
Balsam fir growing in open stands, in pastures, along lake shore 
lines in Ontario, and on islands off the coast of Maine is often 
heavily defoliated. Trees are seldom killed by a single defoliation 
but some are killed by repeated defoliations. Spruce trees in farm 
shelterbelts and ornamental plantings in the Prairie Provinces of 
Canada have also been damaged. The introduced parasite, Dahl- 
bominus fuscipennis (Zett.), has destroyed up to 40 percent of 
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