TRADITIONALLY, pest management
was seen as a battle pitting a farmer and crop-protection
companies against pests.
It was a conflict that could not be buried in time as pests
develop resistance, leading to a cycle of farmers working
to overcome the highly adaptive insects that inch their
way back to crop stands.
However, with science working double time and in the deepest
recesses of genetic materials, improved crop varieties were
produced using genes coming from sources other than those
from the plant genome.
Dr. Candida Adalla, director of the Department
of Agriculture (DA) Biotechnology Implementation Program,
said this “truly revolutionized our crops’ improvement process
and also challenges our way at looking into the strategies
and techniques of managing pest problems.”
Adalla, a professor at the Crop
Protection Cluster of the University of the Philippines
in Los Baños (UPLB), Laguna, said crops have been bred
to combat high-dose insect resistance, which means these
crops are engineered to kill pests en masse.
She cited the current transgenic crops such as the Bacillus
thuringiensis (Bt) corn and Bt cotton, which provide higher
dose mechanisms that wipe out the pest population that attack
genetically modified (GM) crops.
Alongside Bt corn technology is the requirement for farmers
to ensure that resistance management recommendations were
understood and fully complied with, Adalla added.
“This indicates that while the technology promises comparatively
high yield advantage over traditionally bred varieties,
the technology is very much knowledge-based, and this requires
good level of education for the end-users to ensure that
the ecological risks are minimized and they reap economic
benefits,” she noted.
New technologies are actually being developed to increase
and stabilize production due to the current pressure for
food growers to secure increased yield of high-quality crops.
Proper management techniques had not been observed in the
past and experts believe it could be one reason infestation
increased and became serious threats.
In her paper “Management of Pests: Principles, Concepts
and Practices,” Adalla cited some of these technologies
and situations that include:
• Expanded irrigation that allowed intensive cropping and
provided continued food supply.
• Development and expansion of farms for high-yielding
varieties that also required more inputs.
• Increase in fertilizer use that make possible the denser
growth of crops, which rodents and hoppers particularly
• Pesticide use in response to more pest problems may lead
to higher profits but this could only be realized with the
proper use of farm inputs. (However, misuse can result in
more problems and economic yield losses. An example is the
reduction in efficacy of what originally was a very effective
insecticide or technically referred to as insecticide resistance.)
• Expanded cultivation of farmlands, disturbing natural
environments and allowing pests to increase in numbers and
transfer from wild hosts to cultivate species.
Adalla said that pest problems brought about by new production
technologies are not unique to specific environments.
In the past, the response to pest problems was the repeated
use of pesticides.
Over the years, however, the concept of pest control has
changed from dependence to highly toxic, broad-spectrum
pesticides to the use of selective crop-protection products
that are less disruptive of the environment.
The concept of eradication has also changed to management,
bringing about the rational integration of two more control
approaches with the goal of managing pests to reduce their
impact on crop yields.
Adalla said that in integrating two or more control tactics
to ensure effective pest management “the key is population
management and not total eradication.”
Integrated pest management (IPM) would depend on multidisciplinary
ecological strategies that allow agro ecosystem analysis
to understand the effects of each tactic and decide on the
basis of its long-term impact to the pest and crop environment.
Biotech crops and IPM
Although it takes time, examination of crops by walking
through the field is an essential aspect of IPM.
“The most important consideration is that one should know
what to look for, however frequently and over what part
of the plant is normally colonized and damaged,” Adalla
The most important goal of pest management is also the
selectivity of pest-control interventions that seek to curb
the number of pests specified so that it would have minimal
effects on all other components of the environment.
Procedures or pest-control tactics are also devised to
suit current technology and be compatible with economic
and environmental issues and eventual “economic and social
For example, she said that if the Bt corn, a GM technology,
is an option against the dreaded corn borer, then the community
should eventually accept it.
In the end, she said that it is the stakeholders who should
make the decision because “it is their lives and welfare
[that are] at stake.”
In keeping pests from becoming a problem, there is a need
to use resistant varieties, whether they are traditional
Yet, how do GM crops affect IPM tactics and solve the problem
of farmers unable to regularly monitor their crops?
According to Adalla, since technology promises a high mortality
rate on pests, the concern has been on whether the technology
also affects nontarget species, particularly the natural
enemies of pests, and the environment, as well.
She said this is where the refuge crops come in, and they
have yet to be fully understood and appreciated by farmers.
Adalla pointed out that recent studies have shown that
farmers using Bt corn have difficulty accepting the idea
of allocating a portion of their field for another variety
of corn or crop to serve as a refuge, with the possibility
of their being devastated by pests.
She said the current very high rate of adoption of Bt corn
indicates a need to seriously ensure the refuge requirement
is followed “if we are to sustain the gains of this important
Adalla said the way forward is for IPM to become a “way
of life” for Philippine agriculture.
“It’s a shift in how technocrats and farmers look at the
farm and the pest situations and make decisions,” she noted.
When she had a lecture before members of the crop-protection
industry, Adalla advised them that instead of just spending
a lot in developing a product, they should spend “more time
in understanding how to sustainably benefit from it.”
She said that IPM should be given a chance to flourish
among farmers to make their ventures “truly profitable and