Implications of an unintended area-wide IPM for Chilo suppressalis in Japan

This paper discusses the success of an unintended area-wide integrated pest management (IPM) for Chilo suppressalis in Japan. Chilo was considered as one of the country’s major rice insect pests causing significant yield loss during the pre-war period, along with Scirpophaga incertulas . Chilo population density declined through the years, which was considered to be induced by modern farming technologies associated with various improved agronomic practices, particularly farm mechanization, which were aimed at increasing rice production and saving labor rather than decreas ing Chilo population. Based on the case of Japan, other density-dependent factors associated with the low population of Chilo include the following: a) the duration of the IPM scheme, either intended (planned) or unintended, should at least cover a full decade (10 years); b) the area should be wide enough to cover population displacement of Chilo stem borers; and c) integrated pest management of key pests should be implemented in complementation with modern farming technologies. It was also noted that environmental factors associated with the maintenance of low density of Chilo , and possibly its total extinction in the future, must be considered in developing rice management strategy. This includes maintaining a balance between integrated pest management and conservation of the paddy ecosystem, also known as integrated biodiversity management (IBM).