482 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
nacula. The overwintering larvae become active almost coincidentally 
with the bursting of the buds of their food plants. In the Northeast 
this may take place i in April or early May and in the Lake States from 
May to early June. They first tunnel in ‘the old needles and then bore 
into the center of the opening buds, remaining concealed as long as 
the developing foliage permits, and they feed on the pollen in the 
staminate flowers if these are present. As soon as the new growth 
becomes from 1 to 11% inches long, the larvae, then in the fourth and 
fifth instars, begin tying the tips of several twigs together, and later 
this nest becomes quite pronounced. The feeding now is chiefly along 
the side of the lengthening tip, the needles being chewed off from the 
stem, and sometimes the soft bark is gnawed. Because of its habit of 
feeding on the leaf bases, the amount of foliage destroyed exceeds by 
far the actual food requirements. The mature larva spins a loose 
silken web either in the nest or attached to a twig, and within this web 
it transforms to a pupa. 
Adverse weather conditions, diseases, predators, and many species 
of insect parasites normally play an important part in the control of 
this pest. However, when conditions are favorable for its increase the 
combined effects of all the natural enemies do not prevent outbreaks. 
Extensive outbreaks are often brought to an abrupt end by the effects 
of partial or complete starvation of the larvae. In the case of the 
form that feeds on jack pine, the normal fluctuations in abundance of 
staminate flowers from year to year have an important influence on 
the survival of young larvae that have overwintered on the trees. 
Suggestions for preventing serious injury by the spruce budworm in 
spruce-balsam fir forests subject to attack, have been made by several 
investigators. Swaine, Craighead, and Bailey (403) advocated the 
utilization of fir on a short-term rotation. Others included such prac- 
tices as removal of overmature, slow-growing stands of fir; encour- 
agement of mixed hardwood-softwood stands; favoring of spruce 
seed trees in logging, particularly white spruce; avoidance of fir on 
thin soils subject to excessive drying and on poorer sites. Graham 
and Orr (197) recommended that logging operations should be dis- 
tributed so as to result in the breaking up of future balsam fir-spruce 
types into comparatively small blocks of uneven age. This will reduce 
the acreage of such types as will be in a susceptible stage of develop- 
ment at any one time. For preventing budworm injury in Scotch 
pine and jack-pine stands in the Lake States, Graham (792) recom- 
mended the following practices: Maintain fully stocked and even- 
aged stands to prevent development of trees with excessively large 
crowns; fill in openings and do not space seedlings more than 6 by. 6 
feet apart, so that the crowns will close at the age of 10 to 15 years: 
remove susceptible trees in liberation cuttings; reduce staminate flower 
production by the removal of old trees with large crowns; log jack 
pine as soon as it is mature. 
Trees in ornamental plantings can be protected by spraying with 
lead ameenave or DDT (p. 51) just as the shoots are opening in the 
spring. Fair results have been obtained in Canada and New York in 
recent tests with DDT spray applied from airplanes. 
For cautions on the use of arsenicals and DDT, see pages 25 
and 34. 
Argyrotaenia quercifoliana (Fitch) is a cream-yellow moth, dotted 
with brown, and has a wing expanse of about 34 inch. The forewings 
