Insect Pests of Rice in the Philippines--Problems and Management Strategies

다국어 초록 (Multilingual Abstract)

The two major factors that are responsible for low yields are weather (floods, drought and typhoon) and pest epidemics. The tropical rice field of the Philippines is exposed to several organisms that are injurious to the rice plant. About 20 species of insects are considered important pests in the Philippines and at times contribute to low rice yield. These insect pests are divided into stem borers, sap feeders, defoliators, grain feeders and root feeders. Stem borers are chronic insect pests and always found in the field although outbreak proportions are seldom. There is no commercial variety released in the Philippines that is resistant to rice stem borer. The sap feeders are composed of several species of planthoppers, leafhoppers and a pentatomid bug. Most of the planthoppers and leafhoppers are vector of important diseases of rice like tungro, ragged stunt and grassy stunt. The grain feeders are composed of several species of Leptocorisa. A Lygaeid bug was recently reported as a new pest of rice grain in the field. The most common defoliators are leaffolders, whorl maggot and rice caseworm. Root feeders are seldom a problem in irrigated lowland rice in the Philippines. Management of rice insect pests is normally through integration of the different management strategies. These strategies include host plant resistance, biological control, cultural control and the use of insecticides as a last resort. Since a tropical rice ecosystem like the Philippine rice field is rich in communities of beneficial organisms, conservation of these naturally occurring biological control agents like predators and parasitoids is our primary control tactics against insect pests of rice. Maximizing the use of these beneficial organisms is a very important principle in Integrated Pest Management (IPM) of rice insect pests.