Contents - Faperta

16 Biotechnological Approaches for Pest Management and Ecological Sustainability
adjusting the threshold at specifi c times during the crop growth period, which roughly correspond
to the three phases of an insecticide resistance management strategy (Cox et al., 1991).
The model HEAPS incorporates modules based on adult movement, oviposition, development,
survival, and host phenology, and estimates populations in each of a grid of simulation
units into which a cotton-producing region is divided, taking into account both bollworm
species in cotton as well as in other crops, and noncrop hosts in the region (Dillon and Fitt,
1990). A relatively simple simulation model of H. armigera on pigeonpea has been developed by
Holt, King, and Armes (1990) to optimize insecticide use for the control of susceptible and
resistant larvae of H. armigera on pigeonpea. The driving variable is the fl owering phenology
of the crop, on which oviposition time and survival strongly depend. The optimal time and
application frequency to control the progenies of a wholly immigrant population were most
sensitive to the time and duration of immigration, fl owering time, moth age at immigration,
and the development time of young larvae. Like the other models described, this model is also
highly specifi c to the local ecology of the pest and the cropping system in question.
The IPM Practice
In view of the need to make use of and exploit the existing spectra of natural enemies to
reduce excessive dependence on chemical control, particularly where there is resistance to
insecticides, various IPM programs have been developed in which different control tactics
are combined to suppress pest numbers below a threshold (FAO, 1995; Gopal and
Senguttuvan, 1997). These vary from judicious use of insecticides based on ETLs and regular
scouting to ascertain pest population levels to sophisticated systems, almost exclusively
for cotton, using computerized crop and population models to assess the need, optimum
timing, and selection of insecticides for sprays.
Classical integrated management programs for apple pests in Canada (Pickett and
Patterson, 1953) and for cotton pests in Peru (Dout and Smith, 1971) provided some of the
early models for successful implementation of IPM in the fi eld. The FAO subsequently
provided the coordination to spread the IPM concept in developing countries. The success
of an IPM program in rice in South East Asia (FAO, 1995) was based on linking outbreaks
of the brown planthopper, N. lugens with the application of broad-spectrum insecticides,
and the realization of the fact that the brown planthopper populations were kept under
check by the natural enemies in the absence of insecticide application. Much of the impact
of this program was brought out through fi eld demonstrations, training programs, and
farmers’ fi eld schools. As a result, some of the broad-spectrum insecticides were also
banned in some countries. The success of some of these programs has led to the collaboration
of a global IPM facility under the auspices of FAO, the United Nations Development
Program (UNDP), and the World Bank, which will serve as a coordinating and promoting
entity for IPM worldwide. The establishment of International Agricultural Research
Centers (IARCs) has also contributed signifi cantly to IPM, particularly through the development
and promotion of pest-resistant cultivars worldwide.
Is Genetic Engineering of Plants and Biocontrol Agents an Answer?
The promise of biotechnology as an instrument of development lies in its capacity to
improve the quantity and quality of plants and biocontrol agents quickly and effectively.