Impact of - IDL-BNC @ IDRC - International Development Research ...

and locust. Field trials are currently under way and this approach will be tried
in Africa against locust plagues.
Emphasis has been placed on the development of the bacterium Bacillus
thuringiensis (Bt) as a biocide because of its safety to mammals and the
environment. At least 2-3 t/year of commercial Bt products are now used in
developed countries to control insect pests of agricultural crops and forest and
ornamental trees. A small percentage of the biocide is used in developing
countries. The adaptation of the commercial products to local conditions in
developing countries has limited its use there. IDRC support has concentrated
on solving this problem.
Botanicals
In the tropics, a large number of plant species have potential insecticidal
properties. Many plants are used traditionally for fish poisons, arrow poisons,
and human medicines. Some are used by farmers for pest control. Project
teams in the Philippines and Thailand are surveying promising plants, testing
them for insecticidal properties against major insect pests, investigating their
mode of action (specifically looking for new classes of chemicals with novel
modes of action), determining chemical structure and in some cases possible
synthesis, and determining the effects on nontarget organisms and mammalian
toxicity. The safest and most promising insecticides will then be tested in
on-farm experiments for effectiveness under field conditions. These products
may then be extracted locally from cultured plants either on a village or
homestead scale or produced on a larger scale by commercial enterprises.
In Thailand, researchers used a similar approach to identify a botanical fish
poison that may soon be marketed. It will offer a safer, locally produced
alternative to current imported poisons. In these projects, the search is for
effective botanical substances that can be produced locally, are cheaper than
imported products, and have minimal health and environmental effects.
Cultural and ecological controls
IDRC is supporting several projects to examine various aspects of farming
systems in the hope of identifying novel approaches to pest management. The
traditional practice of combining rice and fish culture is expanding rapidly in
Asia. Researchers in China, Indonesia, and Thailand report that the presence
of fish decreases the number of pests and diseases in rice. Also in Indonesia,
researchers are trying to determine how fish can be managed within an
intensive rice-production system where chemical insecticides are used.
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