60 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
fact indicates very strongly that the control of the spruce budworm is 
possible by the use of silvicultural methods. 
It is certain that outbreaks of injurious insects are just as much the 
result of the operation of well defined natural laws as is any other natural 
phenomenon. When a certain amount of heat is applied to water it 
will boil, if the heat is taken away it will cool. Certain factors bring 
about the changes in the biotic balance in a forest and as a result we 
have certain species favored at the expense of others. When the favored 
species is an injurious insect we have an epidemic of the pest. It seems 
reasonable to believe that if we had more knowledge of the factors in¬ 
volved in bringing about or preventing outbreaks that we might easily 
reduce the chance of the occurrence of insect epidemics. 
A PROGRAM FOR FUTURE PROGRESS IN FOREST ENTOMOLOGY 
As already pointed out, the problems of forest entomology divide 
themselves into two groups: 1, those involving the protection of forest 
products and 2, those involving the protection of growing timber. 
Mechanical means are usually available and more or less effective, in the 
first group, but in the second group the mechanical methods are only 
economically applicable under particularly favorable conditions. There¬ 
fore we must largely turn to silvicultural control for insect pests of 
growing forest trees. 
To confine our attention to the development and application of mechan¬ 
ical methods wherever they can be applied has been the tendency in the 
past but the time has now come to turn our attention also to the develop¬ 
ment of silvicultural methods. We can no longer be satisfied with taxo¬ 
nomic and life-history studies of insects in our forests but we must also 
find some means of controlling these pests. We can no longer avoid 
the issue by telling the forester that we will help him as soon as he has 
changed economic conditions to suit our established methods of insect 
control. We must accept economic conditions as they are and if our 
old control methods do not fit we must find new methods which can be 
used. We have already found some encouragement in this new child of 
forest entomology, silvicultural control. Let us develop this phase of 
the work and watch it lead us to successes far in excess of our fondest 
hopes. 
Secretary A. F. Burgess: Although I did not hear all of this paper, 
it seems to me that in addition to the suggestions made, there is need 
for a more thorough study of natural control agencies and the utilization of 
natural enemies on some of these problems. A more intensive study 
