Rodents cause significant damage to agricultural crops throughout the world, including rice, the staple food for the increasing population of Southeast Asia. Little is known about the ecology of pest rodent species, resulting in much effort being concentrated on ineffective, time consuming control practices. This research was designed to understand the demography and habitat use of the major pest rodent (Rattus tanezumi) of the Banaue rice terraces in order to identify the most efficient time and location to undertake pest control. Rodent crop damage and associated yield loss was also assessed in order to provide information for a cost : benefit analysis of rodent control practices. And the beliefs, perceptions and practices of Banaue rice farmers were investigated to assist in identifying future compatible rodent control programs. Replicated cage trapping was undertaken for a twelve month period over the entire rice cropping season in two study sites in the Municipality of Banaue Philippines. The breeding season of R. tanezumi corresponded with periods of food availability from the transplanted to ripening stages of the rice crop. A non-breeding season occurred from the fallow to seedling stages. The distinct breeding season occurred within the rice fields and adjacent village and scrub habitats. Radio-tracked and spool-and-line tracked R. tanezumi moved from adjacent habitats into the rice field during the breeding season, and individuals persisted in all habitat types, including the rice field, during the fallow, nonbreeding season. Overall rice yield was significantly greater (43%) in areas where rodents were excluded by fencing compared to areas where rodents were not excluded. More rodent damage to rice tillers occurred at the booting than at the ripening stage of the rice crop. These results suggest that to prevent rodent damage, control should be undertaken at the end of the R. tanezumi non-breeding season (prior to transplanting), before rodent numbers multiply and crop damage occurs. Further, the cost-benefit analysis of non-chemical rodent control programs in Banaue, suggests that benefits accrue once yield loss is likely to exceed 5%.
| Identifer | oai:union.ndltd.org:ADTP/272937 |
| Date | January 2007 |
| Creators | Miller, Rachel Weslie, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW |
| Publisher | Awarded by:University of New South Wales. |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Rachel Weslie Miller, http://unsworks.unsw.edu.au/copyright |
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