Western Yellow-striped Armyworm Moth

Spodoptera praefica · Order: Lepidoptera · Family: Noctuidae

Also called: western yellowstriped armyworm, yellowstripe armyworm

No source yet on danger. We have no source yet on whether it bites, stings or damages anything.
Western Yellow-striped Armyworm Moth
Photo: Ken-ichi Ueda, CC BY

The western yellow-striped armyworm moth has a wingspan of about 35 to 40 mm. Adults fly in early spring (March-April) and again in late summer (August-September).

Source: Wikipedia

How to recognize it

The fore-wings are paler than those of the similar Spodoptera ornithogalli and lack the blurry white stripe. The hind-wings are white or gray and show a small brown dot on the underside.

Source: Wikipedia

Size

Wingspan ranges from 35 to 40 mm (about 1 ⅜ to 1 ⅜ in).

Source: Wikipedia

Life cycle

Adults are on the wing from March to April and again from August to September.

Source: Wikipedia

When you see it

The moth is active in early spring and late summer.

Source: Wikipedia

Where it is found in the US

Recorded in 13 of 51 states and DC. Most records: Montana, California, Washington, Oregon, Idaho, Utah, Nevada, Wyoming.

Darker = more records. Counts are museum and citizen-science records, not population size.

Source: GBIF

Status: native in North America; native in Canada; native in United States. Source: iNaturalist

Months it is reported in the US

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Source: GBIF

More photos

Western Yellow-striped Armyworm Moth photo 2
Photo: Ken-ichi Ueda, CC BY
Western Yellow-striped Armyworm Moth photo 3
Photo: Trevor Van Loon, CC BY
Western Yellow-striped Armyworm Moth photo 4
Photo: Ken-ichi Ueda, CC BY
Western Yellow-striped Armyworm Moth photo 5
Photo: Trevor Van Loon, CC BY

Questions people ask

When are adult moths seen?

Adults fly in March-April and again in August-September.

Source: Wikipedia

How can I tell it apart from Spodoptera ornithogalli?

The western species has paler fore-wings without a blurry white stripe and a small brown dot on the underside of the hind-wings.

Source: Wikipedia

Same family (Noctuidae)

Ipsilon Dart MothIpsilon Dart MothAgrotis ipsilonDamages trees, gardens or cropsFall Armyworm MothFall Armyworm MothSpodoptera frugiperdaDamages trees, gardens or cropsArmy Cutworm MothArmy Cutworm MothEuxoa auxiliarisDamages trees, gardens or cropsLarge Yellow UnderwingLarge Yellow UnderwingNoctua pronubaDamages trees, gardens or cropsSilver ΥSilver ΥAutographa gammaAmerican DaggerAmerican DaggerAcronicta americanaCan irritate skin

Sources

  • Wikipedia: https://en.wikipedia.org/wiki/Spodoptera_praefica

Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia

Text written 2026-10-24 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-24.

How this page works

This is one bug's fact sheet. The colored box at the top says whether it is dangerous. Sections below cover how to recognize it, whether it is a pest, and how to deal with it. The US map shows which states have records; tap a state to see other bugs there.

Every fact on Bug FAQ comes from a named source (university extension sites, government agencies, GBIF, iNaturalist, Wikipedia). The source is linked next to each section. If we have no source for something, we leave it out.