HomeInternational Rice Research Notesvol. 25 no. 2 (2000)

Rice pest constraints in tropical Asia: quantification of yield losses due to rice pests in a range of production situations

S Savary | L. Willocquet | Elazegui Fs

Discipline: Agriculture, Research



Authoritative estimates of yield losses caused by rice pests in tropical Asia are extremely difficult to obtain because of the diversity of pests, ecosystems, and production situations across this large region. The most often quoted figures are those of H. Cramer (1967, Plant protection and world food production. Plantzenschutz-Nachricten-Bayer), according to which insects caused 34.4% yield loss, diseases 9.9%, and weeds 10.8%. At last, new and more empirically sound yield loss estimates have been published, derived from surveys of farmers' fields and experiments that quantified the association between injury levels and yield loss. Savary et al (2000a) collected data on cropping practices, pest injuries, weather variables, and actual yield estimates from 456 farmers' fields in six sites in four countries. They described five clusters of injury profiles and six clusters of production situations. Injury profiles were associated with production situations and actual rice yields in farmers' fields across Asia. This suggests that pest management strategies should be based on production situations. Some common patterns of cropping practices and injury profiles across tropical Asia, however, were identified, and thus there is also potential for developing pest management strategies which can be considered throughout the region.