Rice gold-fringed borer
Chilo auricilius. Another species, Chilo suppressalis (the Asiatic stem borer, or striped stem borer), occurs in Australia, but not in the rest of Oceania. It is also similar to Chilo polychrysus, which occurs in India, Indonesia and Thailand. A moth in the Crambidae.
Restricted. South and Southeast Asia, Oceania. It is recorded from Papua New Guinea.
Rice, sugarcane, sorghum, maize, and wild grasses.
The larvae do the damage by feeding on the stems and causing similar symptoms to other rice stem borers (see Fact Sheets nos. 408, 409, 411). The larvae tunnel into the stems, through the internodes towards the base of the plant, causing stems to wilt and die, a condition known as 'deadheart'. The stems are easily pulled out (Photo 3). Feeding at the base of the panicles may prevent emergence or result in white unfilled grain of those that have emerged, a symptom called 'whitehead' (Photo 4).
Eggs are creamy-white, slightly flattened, scale-like, laid in 2-5 rows; they turn black later. Larvae are white, growing to 25-30 mm long with five bluish-purple lines along body, and brown heads. Female pupae are 13-14 mm, males slightly shorter, and they are brown. Adult forewings yellowish or brownish with silvery dots and a marginal golden fringe; hindwings are light brown (Photos 1&2). The moth is nocturnal.
The gold-fringed rice borer is considered to be primarily a pest of sugarcane, and only attacks rice occasionally. Another species, the striped stem borer, Chilo suppessalis, is considered to be a far more important species on rice, known to destroy entire fields (see Fact Sheet no. 410).
Look for deadhearts and whiteheads at the vegetative and flowering stages, respectively. Because of similarity with other Chilo species attacking rice, identifications should be done by taxonomists with expertise in the Lepidopteran pests of rice.
Countries not yet infested by the gold-fringed stem borer should consider all likely pathways for entry, and apply quarantine measures accordingly. Many countries throughout Asia, Africa, the Americas and Oceania are at risk. Pathways of introduction are likely to be via produce contaminated by pieces of stem of the hosts infested with larvae or pupae.
In general, the gold-fringed rice borer is parasitised and predated by the same natural enemies as other rice stem borers. In India, the tachnid fly, Stumiopsis inferens, and the wasp, Pycycnobracon mutator, are useful larval parasites, and Trichogramma japonicum and a Telenomus sp. the most effective egg parasioids.
Chilo auricilius usually occurs with other rice stem borers, e.g., Scirpophaga and Sesamia species and is controlled by the same measures applied to them.
Modern rice varieties that are relatively thin-stemmed, short, high tillering, and early maturing, may result in less damage from stem borers generally. This aspect is important as well-grown, vigorous crops can withstand 20% deadhearts and 10% whiteheads before yeild is affected.
As the stem borer is thought to be a minor rice pest, chemical control is likely to be unnecessary. There is also the risk of destroying natueral enemies if it is used. If chemicals are needed:
AUTHOR Grahame Jackson
Information (and Photo 4) from Rice Knowledge Bank. IRRI. (http://www.knowledgebank.irri.org/training/fact-sheets/pest-management/insects/item/stem-borer); and CABI Chilo auricilius (gold-fringed rice borer) (2017) Crop Protection Compendium. (www.cabi.org/cpc); and (including Photo 3) Anderson S, Tran-Nguyen L (2012) Gold-fringed Rice Borer (Chilo auricilius). (Source: N. Sallam DAFF Biosecurity.) PaDIL - (http://www.padil.gov.au); and from Chilo auricilius. Wikipedia. (https://en.wikipedia.org/wiki/Chilo_auricilius).
Produced with support from the Australian Centre for International Agricultural Research under project HORT/2016/185: Responding to emerging pest and disease threats to horticulture in the Pacific islands, implemented by the University of Queensland and the Secretariat of the Pacific Community.
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