Minoru Ichihara

Sustainable Rice Agriculture by Maintaining the Functional Biodiversity on Ridges

The ridges between rice paddy fields, originally constructed for irrigation, also serve as habitats for many organisms, including the rice stink bug Oebalus pugnax (the most important insect pest of rice) and natural enemies of the insect pests of rice. Therefore, the ecological management of these ridges is important for pest control and for the conservation of the natural enemies of rice pests. We identified the following ecological management practices for the conservation of the natural enemies of rice pests and for the control of rice stink bugs: (1) mowing increases the population of wolf spiders (family Lycosidae), which prey on stink bugs; (2) mowing at a high level effectively controls Poaceae plants, which host rice stink bugs; (3) the use of cover plants on ridges increases or maintains the population of wolf spiders, as well as those of crickets (family Gryllidae), which feed on the seeds of harmful plants. The above ecological management practices should decrease the populations of rice pest insects and serve as laborsaving techniques for sustainable rice agriculture.