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Dark-headed stripe borer

Scientific Name
Chilo polychrysus
Scientific Author
(Meyrick 1932)
Taxonomy
(Lepidoptera:Crambidae)
Status
Exotic Species Establishment in Australia
Reliability
High
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Diagnostic Images

Female C. polychrysus
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Caption
ANIC P140 rice sweeping, Humpty Doo, NT, I.Common
Source
S. Anderson DAFF Biosecurity
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Diagnostic Images (8)
Diagnostic Notes
Identification is currently undergoing peer review as part of the National Diagnostic Protocols by SPHDS.

Fresh specimens were unable to be sourced. As specimens become available, data will be added. Surveys are currently being conducted within the wild rice areas of the Darwin and outer island regions to determine definitively the presence and/or extent of Chilo polychrysusin the Northern Territory.

The first obvious symptom of rice stem borer attack is the sign of ‘whitehead’ which is caused by rice stem borer infestation. The plants start to bear panicles which become discoloured and have empty or partially filled grains. Symptoms of borer attack in rice crops vary in relation to the stage at which the crop was attacked. Dead hearts are produced by the larvae feeding on the leaf sheaths of new leaves. The emergence holes are irregular in shape. Young plants can be killed by heavy infestations as the internodes are destroyed by feeding and tunnelling resulting in drying of the central shoot (Kranz et al 1977).

Eggs shiny white clusters which eventually darken in colour and are placed on either side of the plant’s leaves.

Larva dirty white with 5 longitudinal grey violet stripes, dark head and shield.

Pupa 4 apical protuberances with notches near segments 5 to 7.

Adult Yellow brown with small dark spots, 2-3 spots centrally on forewing and span is 16-25 mm (Kranz 1977 & Kalshoven 1981).

C. polychrysus can be easily confused with C. auricilius by adult and larval morphology.

Chilo polychrysus terminal dots indistinct; subterminal line white with few silvery scales; median line distinct, oblique & pale yellow brown; discal dot highly reduced; fringe slightly glossy; hindwing whitish to dirty cream.

Chilo auricilius terminal dots large; subterminal line row of metallic scales close to apical margin; median line metallic; discal dot visible; fringe shining golden; hindwing light brown (Barrion et al 1990).

Genitalia ♂ valva markedly tapering to a narrowly rounded apex; stout setae close to ventral margin at one third distance from base; distinct and heavily sclerotized, notched pars basalis; juxta plate with short arms, tapering, nearly symmetrical aedeagus a little longer than valva; ventral process of aedeagus bifurcate into 2 long narrow arms, each arm with sub basal flap and minute subapical dentation; cornuti absent.

♀ heavily sclerotized area surrounding ostium bursae, some with long band posteriorly divided longitudinally; ostial pouch slightly demarcated from ductus bursae armed with small sclerite either side; ductus bursae behind ostial pouch with a short heavily sclerotized portion, then lighter sclerotized, sometimes swollen in caudal position; signum absent (Bleszynski 1970).

Coming soon - PBT link.
More Information
Specimen Contact
ANIC Collections Manager
Author
S. Anderson & L. Tran-Nguyen
Created
15/02/2012 09:48 AEST
Last Updated
27/02/2012 10:39 AEST
Citation
S. Anderson & L. Tran-Nguyen (2012) Dark-headed stripe borer (Chilo polychrysus) Updated on 2/27/2012 10:39:07 AM Available online: PaDIL - http://www.padil.gov.au.
Image Use
Free for use under the Creative Commons Attribution 3.0 Australia License

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