Beet Armyworm Moth

Beet Armyworm Moth

Spodoptera exigua

Daily sighting probability ~10% · With luck
at Porto

In 3 days ~30% in a week ~60%

216 Verified sightings at Porto
57 In all 5 parks From 2019 to 2026
August Best month
☀️🌙 Day & Night When it's spotted

About the Beet Armyworm Moth

The beet armyworm or small mottled willow moth (Spodoptera exigua) is one of the best-known agricultural pest insects. It is also known as the asparagus fern caterpillar. It is native to Asia, but has been introduced worldwide and is now found almost anywhere its many host crops are grown. The voracious larvae are the main culprits. In the British Isles, where it is an introduced species and not known to breed, the adult moth is known as the small mottled willow moth.

Thought to have originated in south-east Asian countries, it was first discovered in North America about 1876, when it was found in Oregon, and it reached Florida in 1924. The adult is a drab brown or grey moth with a wingspan of 26–32 millimetres (1–1+1⁄4 in). Forewing is greyish ochreous in color, washed with dull yellow and sprinkled with black scales. Inner and outer lines are double, indistinct, filled in with pale yellowish color. A dark waved median shade visible before lower half of outer line. Cell is dark brown. Orbicular stigma is pale or bright yellow, and round, whereas reniform has a curved brown lunule in centre. The submarginal line is pale grey. There is the darker shade... Wikipedia →

Global Distribution

Parks Where Found

# Park Country Daily sighting probability
1 Death Valley National Park 🇺🇸 United States
~10%
2 Sierra Nevada National Park 🇪🇸 Spain
~10%
3 Doñana National Park 🇪🇸 Spain
~10%
4 Joshua Tree National Park 🇺🇸 United States
<5%
5 Pyrénées National Park 🇫🇷 France
<5%

Cities Where Found

# City Country Daily sighting probability
1 Porto 🇵🇹 Portugal
~10%
2 Valencia 🇪🇸 Spain
~10%
3 Madrid 🇪🇸 Spain
~10%
4 London 🇬🇧 United Kingdom
~10%
5 Liverpool 🇬🇧 United Kingdom
~10%
6 Barcelona 🇪🇸 Spain
~10%
7 Austin 🇺🇸 United States
<5%
8 Birmingham 🇬🇧 United Kingdom
<5%
9 San Diego 🇺🇸 United States
<5%
10 Lisbon 🇵🇹 Portugal
<5%

Before you go

What are the chances of seeing a Beet Armyworm Moth in Porto?

With luck

About 10% of wildlife watchers report a Beet Armyworm Moth sighting in Porto on a given day, based on 216 verified sightings from GBIF citizen-science data. It is the 54th most-seen of the 498 insects we can rate there. Over three days the chance rises to about 30%, and over a week to about 60%, if each day is a fresh chance.

When is the best time to see a Beet Armyworm Moth in Porto?

June to August

In those months about 20% of wildlife watchers report a Beet Armyworm Moth in Porto on a given day, against under 5% in December to March, the lowest months. Those are among Porto's driest months, with about 20 mm of rain a month against 140 mm in January.

What time of day is best to see a Beet Armyworm Moth?

Between 8 and 11 pm

Across all the parks we cover, that three-hour window holds the most Beet Armyworm Moth sightings with a recorded time, and about 6 in 10 of them come between 6 pm and 6 am: it is seen both by day and at night.

Is Porto the best place to see a Beet Armyworm Moth?

Yes

Of the 15 cities where we can rate Beet Armyworm Moth sightings, Porto has the highest daily chance: about 10%. Next come Valencia (Spain, about 10%) and Madrid (Spain, about 10%).

Where does the Beet Armyworm Moth sighting chance come from?

GBIF citizen-science records

It is estimated from how often the Beet Armyworm Moth is recorded against all the insects logged in Porto (216 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.

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