Pacific Pests & Pathogens - Mini Fact Sheet Edition

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Rice white borer (408)

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Photo 1. 'Whitehead' - a symptom caused by stem borers: the base of the panicle is damaged preventing it from emerging or, if already emerged, the grain is unfilled and white.

Photo 2. Larva white rice borer, Scirpophaga nivella.

Photo 3. Adult white rice borer (female), Scirpophaga nivella.

Photo 4. Adult white rice borer (male), Scirpophaga nivella.

Photo 5. Adult white rice borer, Scirpophaga nivella (side view).

Photo 6. Damage ('deadheart') to rice stem by Chilo auricilius (damage by Scirpophaga nivella is similar).

Summary

• 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.

Common Name

White rice borer; also known as the paddy stem borer.

Scientific Name

Scirpophaga nivella; however, there are other Scirpophaga species and there has been confusion between them; e.g., Scirpophaga excerptalis is a pest of sugarcane, Scirpophoga incertulas, yellow stem borer, occurs on rice as does Scirpophaga innota, white rice stem borer. Some authors consider Scirpophaga nivella to be the sugarcane top borer, and a miner pest of rice. Additionally, in the introduction to Scirpophaga nivella, PaDIL states: "This species is the same moth as the Australian species, Scirpophaga chrysorrhoa..." These moths belong in the Crambidae.

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