The brown planthopper Nilaparvata lugens infests rice and suck the plant sap. Under high population density it can cause leaves to initially turn orange-yellow before becoming brown and drying (hopperburn) and eventually kill the plant. The plants exposed to high density of the insect show crescent-shaped white eggs inserted into the midrib or leaf sheath. After hatching, white and brown nymphs and adults can be found feeding near the base of the tillers, producing sooty molds at the base of the plant.
Planthoppers can be a problem in rained and in irrigated wetland environments, during the reproductive stage of the rice plant. It also occurs in areas with continuous submerged conditions in the field, high shade, and humidity. Closed canopy of the rice plants, densely seeded crops, excessive use of nitrogen, and early season insecticide spraying (that destroy natural enemies) also favors insect development. Brown planhoppers are usually more abundant in the dry season than in the wet season. Insects can be monitored by bending over the plants slightly, and gently tapping them near the base, to see if planthoppers fall onto the water surface.
Biological treatments can be used at low population densities of the pest. Natural enemies of the brown planthopper include water striders, mirid bugs, spiders, and various egg parasitoids wasps and flies. The insect can be hold in check by flooding the seedbed, for a day, so that only the tips of seedlings are exposed (drowning). Alternatively, small seedbeds can be swept with a net to catch the insect.
Always consider an integrated approach with preventive measures together with biological treatments if available. Insecticides are only recommended if critical numbers are are found, or if more planthoppers than natural enemies are observed. Insecticides that can be used against the pest include buprofezin, dinotefuran, etofenprox, fenobucarb, fipronil, imidacloprid.