Moths of North Carolina
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2 NC Records

Chilo plejadellus Zincken, 1821 - Rice Stalk Borer Moth

Chilo plejadellusChilo plejadellusChilo plejadellus
Taxonomy
Superfamily: Pyraloidea Family: CrambidaeSubfamily: CrambinaeTribe: Chiloini (=unplaced)P3 Number: 80a1440 MONA Number: 5470.00
Identification
Field Guide Descriptions: Online Resources: MPG, BugGuide, iNaturalist, Google, BAMONA, GBIF, BOLDTechnical Description, Immature Stages: Smith (1986).                                                                                 
Adult Markings: The adults are rather nondescript with the palps, head, thorax and forewings being pale brown, yellowish-brown, or dull yellowish-white with darker dusting. The forewings are dotted or dusted with numerous dark brown or black scales, with these often aggregated to form an oblique line of small dark blotches near the center of the wing and just beyond one-half the wing length. A faint light brown to silvery subterminal line is often evident that runs outwardly oblique from the costa for about one-fifth of its length, then runs parallel to the outer margin to the sub-tornal region. The terminal line is represented by a line of seven black dots. Small groups of silvery or golden scales are often present adjoining the terminal dots, along the subterminal line, and occasionally in the center of the wing is association with the dark blotches. The fringe is medium brown and the hindwing is pale white.
Wingspan: 20-40 mm
Adult ID Requirements: Identifiable from good quality photos of unworn specimens.
Immatures and Development: The larvae feed on cultivated rice (Oryza sativa) and other grasses that are near rice fields. The following is a summary of the life history when using rice, and based on descriptions by Smith (1986), Saichuk (2012) and the University of Arkansas Division of Agriculture (anonymous, 2012).

The last instar larvae from the last seasonal brood overwinter in rice stubble and other nearby grasses. They pupate during the spring, with the adults emerging in May and June in Arkansas and Louisiana. The females lay masses of around 10-30 overlapping eggs on the leaf blades or leaf sheaths. The hatchlings emerge in about 5 days and make their way either to a leaf sheath or base of a developing panicle and chew a hole into the stem. Multiple larvae may enter the stem from a single chewed hole, but typically only one survives to pupate. The larvae feed on the inner stem tissues and with time eat into the lower, larger part of the stem. Damage to a non-fertile plant may cause the whole plant to die or just the central culm, while damage to a developing panicle will cause the developing florets to die and turn white, causing ‘whiteheads’. The final instar eventually moves to the first joint above the waterline and chews through tissues until only a single thin layer of tissue remains. It then chews a circular hole in the stem that serves as an exit hole for the adult, and constructs a silken web within the stem where the larva pupates. The adults emerge after 7-10 days. There are typically three generations per year in the southern U.S. (Smith, 1986). The older instars are yellowish-white with a dark brown head capsule, and have four parallel brown stripes along their dorsal side (Beuzelin et al., 2016).
Larvae ID Requirements: Identifiable from close inspection of specimens or by DNA analysis.
Distribution in North Carolina
Distribution: Chilo plejadellus is associated with marshes and rice fields and is found in two general areas in eastern North America. The first includes populations that are found in northeastern North Dakota and Minnesota southeastward through the Great Lakes region of the U.S. to northern Ohio, then northeastward through southern Canada and adjoining areas of the northern U.S. to Vermont, New York, Ontario and Quebec. The second group follows the Atlantic coastline from Massachusetts and New Jersey southward to North Carolina, Georgia and Florida, then westward across the Gulf Coast to the rice fields and marshlands of Louisiana, Texas and Arkansas. As of 2023, we have only two records, including from a coastal wetlands site in Jones County, and along the Outer Banks.
County Map: Clicking on a county returns the records for the species in that county.
Flight Dates:
 High Mountains (HM) ≥ 4,000 ft.
 Low Mountains (LM) < 4,000 ft.
 Piedmont (Pd)
 Coastal Plain (CP)

Click on graph to enlarge
Flight Comments: The adults have been observed from April through September in different areas of the range. Our two records as of 2023 are from April and June.
Habitats and Life History
Habitats: This species is generally associated with open marshy habitats and rice fields.
Larval Host Plants: The larvae feed on cultivated rice (Oryza sativa) in the U.S. and can be a minor pest. Other reported hosts (Smith, 1986; White et al., 2005) include Annual Wild-rice (Zizania aquatica), Southern Wild-rice (Zizaniopsis miliacea), Saltmarsh Cordgrass (Spartina alterniflora) and Big Cordgrass (Spartina cynosuroides). Saichuk (2012) noted that the larvae in Louisiana initially feed on other grass hosts on the margins of rice fields, then use rice as the stem diameters of the rice plants become large enough to support tunneling larvae. This is supported by the fact that whiteheads of cultivated rice are more numerous on the edges of rice fields, on edges adjacent to levees, and in nearby ditches. - View
Observation Methods: The adults are attracted to lights and the larvae can be found in the stalks of rice or other hosts that show evidence of damage.
Wikipedia
Status in North Carolina
Natural Heritage Program Status:
Natural Heritage Program Ranks: GNR [S1-S2]
State Protection: Has no legal protection, although permits are required to collect it on state parks and other public lands.
Comments: This species appears to be rare in North Carolina and in many areas along the Atlantic Coast where it frequents marshlands. More information is needed on its preferred habitats and host species before we can accurately assess its conservation status within the state.

 Photo Gallery for Chilo plejadellus - Rice Stalk Borer Moth

Photos: 4

Recorded by: Britta Dace Muiznieks on 2014-04-30
Dare Co.
Comment: 		Recorded by: Britta Dace Muiznieks on 2014-04-30
Dare Co.
Comment:
Recorded by: J.B. Sullivan on 2006-06-24
Jones Co.
Comment: BOLD specimen.		Recorded by: J.B. Sullivan on 2006-06-24
Jones Co.
Comment: BOLD specimen.