Rats in rice—ecological solutions show potential

Bandicota indica Hatsua (Photo by K. Aplin)

Across Asia, rats and mice cause substantial preharvest losses of rice ranging from 5% in Malaysia to 17% in Indonesia. To put this into perspective, a loss of 6% in Asia amounts to enough rice to feed 225 million people—roughly the population of Indonesia—for 12 months. Rat damage is often patchy and family rice plots small, so it is not uncommon for farmers or villagers to lose half of their entire rice crop to rats.

Rodents also have an enormous economic impact on stored grain in developing countries. Rats need to eat 10–15% of their body weight each day and contaminate many times more with their droppings. However, apart from recent studies in rural villages in Bangladesh and Myanmar (yet to be published) little has been done to measure this impact.

Currently, many small holder farmers react too late to rodent outbreaks and then have to rely heavily on chemical poisons (rodenticides). These rodenticides are sometimes used wrongly, presenting risks to animals that eat rats and mice (cats, dogs, birds of prey, native cats), to the environment and to humans. Ecologically based methods for management of rats in lowland rice ecosystems have proven effective if applied by communities.

In 2001, the IRRC established a Rodent Ecology Work Group (REWG) under the leadership of Grant Singleton and KL Heong. The REWG was rolled into the Productivity and Sustainability Work Group in 2005. The high level of interest in rodent pests in rice agro-ecosystems has led to the development of this section in the IRRC web site that highlights some latest developments on rodent biology and management.

In collaboration with the Australian Commonwealth Scientific and Research Organisation (Peter Brown, CSIRO Sustainable Ecosystems; and Lyn Hinds CSIRO Entomology), the IRRC has helped develop an effective network of rodent scientists in Asia. 

This Web page contains:

1. Some basic facts on rodent pests in Asia
2. Recommendations for ecologically based rodent management in lowland rice ecosystems
3. Reference to resources materials on the management and biology of rodent pest populations
4. Current IRRC projects in South and Southeast Asia
5. Student projects—current and potential
6. Reference to latest scientific publications
7. Links to web sites of major international rodent projects

The rat—a significant pest

back to top

Rats in rice—ecological solutions show potential

Rats and ecologically based management

Rats and disease

Publications

News and features

Student projects

Links