Restricted. South and Southeast Asia, Oceania. In Australia, Fiji, New Caledonia, Papua New Guinea.
Minor pest. Mostly rice, but also sedges. Damage worse if infestation after panicle initiation and flowering.
Larvae bore into rolled leaves, and then through internodes to the growing point, killing it; stems pull out easily (‘deadhearts’). Panicles fail to emerge, or emerge with unfilled grain (‘whiteheads’).
Eggs on underside of leaf; brownish-yellow larvae, becoming whiter, with reddish line along back. Adults white (males with four dark spots on each forewing). Strong flyers. Nocturnal.
Natural enemies: many egg and larval parasitoids and predators.
Cultural control: handpick in nursery; plough land well (burying larvae/pupae of previous crop); plant at higher density than normal; rotate, e.g., legumes; synchronise plantings with neighbours; submerge eggs by raising water occasionally; weed; apply split applications N; harvest at ground level to remove larvae; plough in stubble, unharvested plants and weeds; use resistant (short, high tillering, early maturing) varieties.
Chemical control: unlikely to be needed. Use abamectin. Avoid broad-spectrum insecticides to preserve natural enemies.