The effectiveness of chemicals in suppressing many forest insect populations has 
been amply demonstrated. A large number of new insecticides and methods of 
application have come into extensive use, and outbreaks covering thousands of 
square kilometers of forest have been suppressed. As effective as insecticidal 
control has been, however, it has not proved to be an unmixed blessing. Chemical 
insecticides have been associated with known or suspected adverse side effects 
caused by some of the more commonly used chemicals. This stems from the fact 
that these chemicals are nonspecific and may be harmful to at least some other 
exposed animal species (254). The problem is compounded in that some chemical 
insecticides are very persistent (953, /358), that all of the material applied in a 
given environment may not remain there, and that free-ranging animals cannot be 
excluded from sprayed areas (560). The deleterious effects of these insecticides on 
food chains are known by the failure of carnivorous birds to reproduce (585) and by 
the appearance of fish unfit for human consumption. Public awareness of known 
and possible hazards associated with the use of these chemicals has given rise to 
concern over their continued widespread use. 
Efforts are unceasing to discover and develop new and safer insecticides (/00S). 
Insecticidal accumulations in the tissues of wildlife need to be determined as a basis 
for indicating when undesirable damage to the biota might occur. Application 
techniques and equipment are being refined to provide better control of the place- 
ment of insecticides in the environment and to further lessen the dangers of 
undesirable side effects. Studies are being made to improve sampling and biolog- 
ical evaluation techniques as a basis for improving the timing of application and to 
ensure that insecticides are applied in the proper amount, and only when and where 
they are needed. Joint genetic and toxicological studies should lead toward efficient 
application and minimal environmental contamination (//66, 1167). 
The rapid changes occurring in the development and use of insecticides in forest 
insect control make it inadvisable to include control recommendations in this 
publication. Furthermore, no insecticides should be used to control an insect unless 
recommendations are registered by the Environmental Protection Agency (/225). 
When using any pesticide, remember to: (1) read the entire label before opening the 
container, (2) meticulously follow application and disposal directions, and (3) be 
certain to consult your County Agent or another specialist regarding any use not 
explicitly mentioned on the label (1/225, 1242, 1273). 
Other Approaches to Control 
Many conventional methods of suppressing forest insect populations are effec- 
tive, but they are all found wanting in important respects. Insecticides are often 
entirely effective, but they usually cannot be applied to large areas without en- 
dangering other forms of animal life. Furthermore, they usually do not hold pest 
populations to subeconomic levels for long, nor do they reduce the vulnerability of 
stands to future outbreaks. Most forms of biological control cannot be depended 
upon to suppress an outbreak before damage has occurred. They may also be 
incapable of preventing outbreaks, although they may reduce their frequency of 
occurrence and their magnitude, intensity, and duration. Because of these deficien- 
cies, aS well as those of other current methods of control, intensive research 1s 
underway to develop new or improved methods and materials which may be used as 
complements, supplements, or substitutes for them. 
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