Most of the important pest species in eastern forests lend them- 
selves to some form and degree of integrated control. The long 
life of the forest crop and the fact that many species of commer- 
cially valuable trees can withstand some degree of infestation 
without serious damage provides the opportunity in the majority 
of cases to utilize different methods of control. 
Since the early days of this century, considerable emphasis has 
been placed on the importation and augmentation of natural ene- 
mies of many species of introduced pests. In many cases, the rate 
of dispersal of these imported enemies has been speeded up by 
the liberation of colonies in many parts of infested areas. The 
build-up in numbers after successful establishment of several 
species has also been speeded up by the liberation of large num- 
bers of field-collected or laboratory-reared individuals. 
The presence and abundance of natural enemies is taken into 
consideration in deciding whether to suppress an outbreak and 
in planning how to accomplish it. For example, the sudden ap- 
pearance of a virus disease in heavily infested stands usually por- 
tends the imminent collapse of the outbreak. Therefore, when 
evidence of this disease is encountered during surveys, it is often 
decided to withhold other methods of control, such as the appli- 
cation of insecticide. Observation of abnormally high percentages 
of natural control provided by insect parasites and predators may 
lead to a similar decision. In other situations where insecticidal 
control is deemed necessary, it is often possible to limit spraying 
to designated portions of infested areas because of the abundance 
of natural enemies in other portions (423). 
Knowledge of the population dynamics of a pest species pro- 
vides opportunities for various other means of preventing or 
reducing losses caused by it, thereby obviating the need for di- 
rect, suppressive measures to control outbreaks. Depending on 
the situation, outbreaks of certain leaf-feeding insects may be 
prevented or minimized by modifying the composition and den- 
sity of susceptible stands. It is often possible to prevent or sup- 
press outbreaks of some bark beetles by the removal of infested 
slash or the salvage of infested trees before the emergence of beetle 
broods from the bark. The utilization of mature trees growing on 
poor sites before they begin to deteriorate and become attractive 
to borers, such as the bronze birch borer, is a recommended con- 
trol practice. The avoidance of unfavorable sites in planting pro- 
grams is recommended for preventing damage by certain species 
(318). Adherence to good construction methods in the building 
of structures obviates the need for chemical control of termites 
later on (630). The destruction of elm material suitable for breed- 
ing by the smaller European elm bark beetle reduces the need for 
the use of insecticides in Dutch elm disease control (763). 
Some of the new approaches to biological control, many of 
which are yet to be perfected, may be expected to provide addi- 
tional opportunities for the integrated approach to control in 
the next few years. For a discussion of the integrated control 
concept, see Stern et al. (691). Comprehensive treatments of 
insect-pest control management and control has also been pub- 
lished (557, 416). 
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