and Integrated Pest Management - part - usaid

4.4 PESTICIDE MANAGEMENT AND IPM IN SOUTn1EAST ASIA
levels of N fertilizer. Populations of tile BPI- have been shown to triple with an
increase in N fertilizer in greenhouse studies (Heinrichs & Medrano 1985).
The increased yield potential of the modern varieties has also resulted in
greater returns from pesticide applications and has thus made it more economical
to apply pest control measures than was the case for the lower yielding,
traditional varieties. Thus, mAional production programs have encouraged the
use of insecticides, and have in sonic cases heavily subsidized their use. The
misuse of insecticides has resulted in de development of resistance, destroyed
natural enemies, and sfimulatc:l the rcproductive activity of the BPI, resulting in
outbreaks due to resurgence (H-lcinrichs anO Mochida 1984).
The pest problems brought aboul . the modern technology are certainly
not unique to rice. The phases that c., ain cotton insect protection programs
have gone through have been classified by R. F. Smith and cited by Luckmann
and Metcalf (1975):
(1) Subsistence phase - a traditional system where there is no organized
crop protection program.
(2) Exploitation phase - crop protection programs consist primarily of
pesticides to protect new varieties.
(3) Crisis phase - after several years of heavy insecticide use, insects
become resistant, and secondary pests become serious pests as their
populations resurge.
(4) Disaster phase - insecticide use increases to a point where the crop can
no longer be grown profitably, and the pest control program collapses.
(5) Integrated control phase - an integrated pest management (IPM) system
is implemented to bring die production system back to profitability.
Most rice insect control programs fit into the exploitation phase, and in
some regions they have reached the crisis phase. Some regions have gone to the
integrated control phase without passing through the disaster phase and
sometimes even bypassing the crisis phase. This is commendable. IPM
systems need to be implemented early to avoid the problems described above for
cotton, and in this paper, I will discuss the role that resistant varieties play in
such systems of pest control.
RICE IPM SYSTEMS IN SOUTHEAST ASIA
In this paper, IPM is considered a system of crop protection where pests are
maintained at populations below the economic injury level through the use of
two or more control methods. It is a strategy that utilizes various control tactics
- cultural, host plant resistance, biological, and chemical - in a harmonious way
and which is ecologically, sociologically, and economically acceptable.
Monitoring
IRRI and national rice research programs throughout Southeast Asia have
been instrumental in developing monitoring techniques for rice pests which are
suited to local conditions. For some insects, sequential sampling plans are