Adults occur in macropterous (long-winged) and brachypterous (short-winged) forms. The macropterous form is about 3.5 - 4.5 mm (0.14-0.17 inch) in length. The body is brown, and the wings are transparent, with very conspicuous veins. Young nymphs are white, but they gradually become darker in older instars.
Damage: Both nymphs and adults penetrate the tissues of their rice host plants with their piercing-sucking mouthparts in order to ingest phloem-sap. Loss of nutrients and obstruction of vessels cause yellowing of leaves. Later, the plants wilt, gradually drying up and eventually dying off. An increasing population density of planthoppers eventually leads to so-called „hopperburn“: groups of dead plants appearing as brown and often lodged patches in the rice field; these patches continue to grow as the insect spreads.
Less severe infestations can still result in reduced plant vigor, smaller panicles, fewer ripened grains and lower grain weight. In addition to the direct damage it causes, the brown planthopper is an important vector of rice grassy stunt virus and rice ragged stunt virus.
All stages of N. lugens excrete honeydew, thus promoting the growth of sooty mold.
The insect prefers to feed on leaf blades and leaf sheaths at the base of plants, where it is shaded and humidity is high. Damage is generally greater in the wet season than in the dry season.