General Insect Management 737
In addition to the public awareness resulting from Rachel Carson’s book, there was an ongoing
push in the scientific community to deal with the impacts of the over use of insecticides by promot-
ing alternate management tactics, including biological control. Interest in biological control had had
a long history as evidenced by the early historical reports mentioned at the beginning of this chapter.
Even just before and during the “golden age” of insecticides from 1939 into the 1960s, biological
control was being studied. The earliest studies during this period were included in broader discus-
sions of population dynamics (Smith 1935; Solomon 1949, 1957). However, there was a gradual shift
to papers emphasizing biological control (e.g., DeBach 1951, DeBach and Bartlett 1951), leading to a
seminal paper by Stern et al. (1959) that promoted and provided a conceptual framework for the inte-
gration of biological and chemical control. Fundamental to this framework were the economic injury
level and economic threshold concepts, which recognize that insect pest populations often occur at
levels below which the value of yield loss that they cause is less than the cost of preventing that loss.
Together, these concepts provided a basis for determining when insecticide applications are justified.
Although these two controls often were thought to be alternatives, they could be complementary and
even augmentative. Stern et al. (1959) noted that biological control operates to permanently increase
the general environmental resistance to the increase of a pest population, whereas chemical control
constitutes short-term restricted pressure. Finally, they noted that one must “recognize the “‘oneness’’’
of any environment, natural or man-made.” The abiotic and biotic components together make up the
ecosystem. “If an attempt is made to reduce the population level of one kind of animal (for example, a
pest insect) by chemical treatment, modification of cultural practices, or by other means, other parts of
the ecosystem will be affected as well. For this reason, the production of a given food or fiber must be
considered in its entirety. This includes simultaneous consideration of insects, diseases, plant nutrition,
plant physiology, and plant resistance, as well as the economics of the crop.” Further, DeBach (1964)
stated, “The prime requisite for integrated pest control is basic ecological knowledge of the entire com-
plex involved including the extent of biological control of each host insect that occurs in the absence of
treatment. Basic studies may take several years to reveal the best method of utilizing the chemicals that
are found to be absolutely necessary, with the biological control that is known to occur if no chemicals
are used.” Finally, Doutt and Smith (1971) stated that there was a great deal of misunderstanding of
what was meant by “integrated control.” They further stated, “There are several unique aspects to the
research upon which an integrated control program is built. One is philosophical since the researchers
must believe that chemical treatments ought not to be applied until they are clearly needed. Another
aspect is organizational in that the program is best developed by a team of specialists representing
diverse disciplines but all of who are channeling their research toward a common goal. The third and
fundamental aspect is that the program is based on a sophisticated understanding of the ecology of the
ecosystem involved.”
Today, integrated control has evolved into Integrated Pest Management (IPM), which is based on a
more holistic approach. IPM frequently is utilized in crop protection with the goal of eliminating or
reducing the amount of pesticide used. As noted at the beginning of this chapter, IPM is defined as “A
decision support system for the selection and use of pest control tactics, singly or harmoniously coordi-
nated into a management strategy, based on cost/benefit analyses that take into account the interests of
and impacts on producers, society, and the environment” (Kogan 1998). Such management practices help
control pests but affect the environment as little as possible.
16.3 Modern Era
16.3.1 Current Management Practices
16.3.1.1 Cultural Control
Cultural control is the use of agricultural practices to reduce crop injury from pests. Because these are
agricultural practices, these practices already are used for the purpose of growing the crop. However, to
be considered a cultural control for a pest, the choice of an agricultural practice must be for preventing