Asian countries have a long history of serious rat damage to rice, coconut,
and other staple crops. In the 1950s, extensive crop losses in the Philippines
during rat population irruptions resulted in international relief efforts
to prevent starvation in rural areas. Several U. S.-sponsored research
and operational efforts provided insights and limited relief. Dry season,
village-wide baiting programs with 1080 or zinc phosphide became the
mainstay of rodent control efforts. In June 1968, the Denver Wildlife
Research Center (now the National Wildlife Research Center, NWRC), with
support from the U. S. Agency for International Development (for a cooperative
program that lasted 25 years), established its first overseas field
station., the Rodent Research Center (RRC), on the campus of the University
of the Philippines College of Agriculture.
NWRC Staff Assigned to the Philippines
F. Nelson Swink 1968-1972
G. Keith LaVoie 1968-1970
Gerry A. Atwell 1969-1971
Richard R. West 1970-1973
Michael W. Fall 1971-1975
Russell F. Reidinger, Jr. 1974-1978
Lynwood A. Fiedler 1978-1983
Melvin G. Garrison 1980-1982
The Philippine staff of the RRC grew from 2 at its establishment in
1968 to more than 30 by the mid-1970s, to more than 100 after the development
of its successor organization, the National Crop Protection Center and
7 Regional Crop Protection Centers in 1976.
The mission of the new institution was to develop more effective methods
of rodent control in rice production, to identify safer rodenticides
for agricultural use, and to assist the Philippine government in training
wildlife damage specialists. The challenge was to coordinate a program
across an agricultural archipelago (more than 7,000 islands spread across
more than 1,000 miles)
with diverse culture and an established bureaucratic structure (more
than 600 government employees involved in rodent control). In 1971,
the research focus changed (tied to Green Revolution objectives) to
determining what a small farmer with 1 or 2 hectares could do to protect
his rice crop using locally available materials, regardless of activities
on neighboring farms. In 1975, following success in achieving the initial
objectives, the Center began to develop similar approaches to protect
coconut, corn, and other crops from rodent damage and investigations
of bird problems in Philippine agriculture.
Some Research Accomplishments
Rodent Identification: Several hundred rodent specimens were
collected from agricultural areas on major islands among the country’s
7,100 islands. Morphometric work, museum comparisons, and chromosome
studies were conducted to identify species. Representative specimens
were deposited in the Smithsonian Institution, including the major pest
species: Rattus rattus mindanensis (now Rattus tanezumi),
Rattus argentiventer, and Rattus exulans.
Damage Assessment: NWRC statisticians devised an index to
assess rat damage to rice based on cut stems observed at harvest and
a national sampling scheme was conducted in wet season and dry season
crops over a 3-year period. About 90% of rice fields had measurable
damage; about 7% had damage over 10%. Overall damage averaged 3.5% of
cut stems at harvest.
Rodent Ecology and Behavior: Rattus tanezumi and
Rattus argentiventer bred throughout the year in ricefield
areas, whenever food and cover were available; peak reproduction occurred
during the wet season – from May to December. Beginning in the
1960s, farmers changed from growing 1 annual rice crop that matured
in 8 months to 2 or 3 crops of Green Revolution varieties that matured
in 16 weeks or less. The high yielding rice varieties, responsive to
fertilization, irrigation and pest control, produced both ecological
and human social changes that had important effects on rodent population
and damage patterns.
Sustained Baiting with Anticoagulant Rodenticides in Rice and Corn:
A highly effective technique, devised and tested extensively on small
rice farms, involved a self-monitoring system of weekly adjustment of
bait station numbers in relation to bait consumption by rats. Bait made
from locally available anticoagulant rodenticide concentrates, such
as warfarin, diphacinone, or racumin, could be prepared on farm with
broken rice. Baiting started shortly after planting and continued until
grain heads began to harden; rodenticide use was minimized by bait placement
in relation to bait consumption. Damage by Rattus tanezumi
and Rattus argentiventer, even in areas where crops could not
previously be grown, could be held to less than 1%. These recommendations
were incorporated in a Green Revolution rice production program that
allowed farmers to avail of low cost rice production loans.
baiting to Control Rodent Damage to Coconut: Anticoagulant rodenticide
baits prepared on farms in 100 g packs and placed monthly in the crowns
of every 10th coconut tree proved highly effective in reducing rat damage
maintaining it at low levels indefinitely. In test plots, yield increases
averaged more than 2-fold over a 3-year period. Reductions in fallen
maturing nuts, which had long been used to estimate rat damage, accounted
for only about 5% of the overall yield increases, suggesting rats also
affected flowers or setting of young fruits. The method required less
than one-fourth the amount of bait needed for intensive ground baiting
in coconut groves and has been applied worldwide.
The Rodent Research Center (RRC) was originally administered by a Board
of Directors composed of more than 20 U. S. and Philippine agency representatives.
After 3 building cycles to expand facilities and construct faculty housing
on the Los Baños campus, it ultimately became an administrative
unit within the College of Agriculture at the University of the Philippines
in Los Baños. In 1976, RRC was succeeded by a new institution,
the National Crop Protection Center (NCPC), with initial funding arranged
through a long-term, low interest loan from the United States. A new
headquarters building, pens and support structures, two additional faculty
houses, and a dormitory for trainees were constructed. Seven regional
crop protection centers were also established to work with scientists
Staff members assisted the University of the Philippines in establishing
an inter-disciplinary wildlife management program and a graduate program
in vertebrate pest management that served students from the Philippines
and a number of other countries. More than 30 graduate students were
supported through the NWRCprogram. A 10-month certificate program for
training of mid-career government pest control personnel in crop protection
technology became a model for establishing mid-career training programs
at the university. Research workshops and U. S.-supported commodity
packages helped to establish rodent control research programs in government
agencies Korea, Thailand, Indonesia, Malaysia, Laos, Cambodia, Vietnam,
and Nepal. Rodent control training for 2,000 agricultural technicians,
other workshops, multi-media packages, and training materials brought
rodent control information directly to farm families.
For more information on work of NWRC’s Philippine Field Station
and its 25-year association with the U. S. Agency for International
Development, search the NWRC catalog for published and unpublished progress
reports and see:
FALL, M. W. 1977. Rodents in tropical rice. College of Agriculture,
Technical Bulletin No. 36, University of the Philippines at Los Baños,
College, Laguna, Philippines.
FALL, M. W. AND J. P. SUMANGIL. l980. National rat control program
in the Philippines. Pages 9 15 in Small mammals: problems and
control. BIOTROP Special Publication No. 12 (Bogor, Indonesia).
FIEDLER, L. A., M. W. FALL, AND R. F. REIDINGER, JR. 1982. Development
and evaluation of methods to reduce rat damage to coconut in the Philippines.
Proceedings of the Vertebrate Pest Conference 10:73 79.
W. H. Ressig, E. A. Heinrichs, J. A. Litsinger, K. Moody, L. A. Fiedler,
T. W. Mew, and A. T. Barron. 1986. Illustrated guide to integrated pest
management in rice in tropical Asia. International Rice Research Institute,
Los Baños, Laguna, Philippines.
FALL, M. W. 1991. Controlling rice losses to rodents in rural communities.
1991. Pages 7-16 in G. R. Quick, editor. Report of the International
Rice Research Institute Expert Panel Meeting on Rice Rodent Control,
International Rice Research Institute, Los Baños, Laguna, Philippines.
FIEDLER, L. A., M. W. FALL, R. L. BRUGGERS AND J. W. DE GRAZIO. 1991.
Rodent and bird problems in agriculture and their management in developing
countries. Pages 65-73 in E. D. Magallona, editor. Proceedings
of the 11th Int. Congr. Plant Protection Vol. 1, Manila, Philippines.
Philippine National Crop Protection Center website: http://www.uplb.edu.ph/ca/ncpc/ncpc.html