search of new foliage. Full-grown larvae drop to the ground, enter the soil, and spin 
tough, reddish-brown cocoons in which they become adults or spend the winter as 
prepupae. In the South there may be three generations per year; in some Northern 
States and Canada there is only one. Population development can be monitored by 
use of a synthetic attractant (/296). 
The redheaded pine sawfly 1s one of the most widespread and destructive of the 
pine sawflies. It usually feeds on young trees, preferably those from 0.3 to 4.6 m 
tall (769). Trees growing under stress on shallow soils, very wet or dry sites, or 
subject to severe competition from hardwoods, bracken fern, or other vegetation are 
especially susceptible to infestation, heavy defoliation, and damage (3/). Out- 
breaks occur frequently throughout the range of this sawfly. 
A nuclear polyhedrosis virus formulated for field use at the Canadian Forest Pest 
Management Institute has proved to be effective in controlling the redheaded pine 
sawfly (292, 1293). The native egg parasite, Closterocerus cinctipennis Ashmead, 
and the larval parasites such as Spathimeigenia spp. are also effective in helping to 
control this sawfly (92, 342). 
A number of management practices have been suggested for preventing damage 
in plantations by the redheaded pine sawfly: (1) Remove competing vegetation such 
as hardwoods or dense bracken fern before planting sites to hard pines; (2) avoid 
planting on high hazard sites covered with hardwoods or dense vegetation, in frost 
pockets, or on soils that are excessively wet, dry, or very low in nutrients; and (3) 
promote early closure of plantations by planting pines with spacing not greater than 
1.8 by 1.8 m in the North Central States. 
The Virginia pine sawfly, NV. pratti pratti (Dyar), has been recorded from New 
Jersey and Maryland to North Carolina westward to Illinois. Its main hosts are 
Virginia and shortleaf pines; other pines are sometimes infested. Newly hatched, 
feeding larvae are pale green, with black head capsules, and are about 3 mm long. 
Full-grown larvae (fig. 180) are spotted or marked with longitudinal black stripes 
and are from 16 to 23 mm long. 
F-519912 
Figure 180.—Larvae of the Virginia pine 
sawfly, Neodiprion pratti pratti. 
385 
