Beet armyworm

Last updated

Beet armyworm
Spodoptera exigua1.jpg
Small Mottled Willow Moth.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Superfamily: Noctuoidea
Family: Noctuidae
Genus: Spodoptera
Species:
S. exigua
Binomial name
Spodoptera exigua
(Hübner, 1808)
Synonyms
  • Noctua exiguaHubner, 1808
  • Caradrina venosaButler, 1880
  • Laphygma exigua

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. [1] 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. [2]

Contents

Discovery

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. [3]

Larva Spodoptera exigua.png
Larva

Description

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 preceding it with dark streaks between the veins. Terminal spots are black. Hindwings semihyaline are white, with the veins dark brown. All three margins are shaded with fuscous color. [4]

Larvae are pinkish brown, clotted with black. Spiracular line pale ochreous, with dark upper edge. They are greenish-brown cutworms, soft and bulging caterpillars with dark longitudinal stripes. [5]

Damage

The larvae feed on the foliage and fruits of plants, and can completely defoliate small ones. Smaller larvae devour the parenchyma of leaves, so all that remains is the thin epidermis and veins. Larger larvae tend to burrow holes through thick areas of plants. For example, they will burrow straight into a head of lettuce rather than neatly removing tissue from one particular leaf, rendering the produce unmarketable. Larvae also attack buds and new growth on plants, preventing flowers from opening, new leaves from sprouting, and vegetables from developing. As the smaller larvae move about they leave strands of silk behind, netting the leaves with a silvery film. [3]

Illustration Spodoptera exigua.JPG
Illustration

Ecology

The wide host range of the beet armyworm includes asparagus, beans and peas, sugar and table beets, celery, cole crops, lettuce, potato, tomato, cotton, cereals, oilseeds, tobacco, cannabis, many flowers, and a multitude of weed species. [6] The beet armyworm does not tolerate cold. It can overwinter in warm areas, such as Florida and Hawaii, but in colder areas, it dies off during the winter and the region is reinvaded by the adult moth as the weather warms and crop plants sprout. [3]

Control

Pheromone traps and mechanical hand picking of adults and caterpillars are extensively used. Parasitoids such as Chelonus insularis , Cotesia marginiventris , Meteorus autographae , Lespesia archippivora lay eggs on the caterpillars, and their larvae feed and emerge. Predators like Orius sp., Geocoris sp., Nabis sp., Podisus maculiventris are also effective controlling measures. Pupal stages can be eliminated by introducing Solenopsis invicta to the field. [3]

Apart from biological control, many chemical pesticides are extensively used. Larvae are susceptible to neem products. Eggs can be killed by using petroleum oil concentrations. Applying cottonseed oil to leaves can eliminate both eggs and larvae. [3]

See also

Related Research Articles

<span class="mw-page-title-main">Nutmeg (moth)</span> Species of moth

The nutmeg, also known as the clover cutworm, is a moth of the family Noctuidae.

<span class="mw-page-title-main">Shark (moth)</span> Species of moth

The shark is a moth of the family Noctuidae. The species was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae.

<span class="mw-page-title-main">Small angle shades</span> Species of moth

The small angle shades is a moth of the family Noctuidae. It is distributed throughout the Palearctic. The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae.

<span class="mw-page-title-main">Angle shades</span> Species of moth

The angle shades is a moth of the family Noctuidae. The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. It is distributed throughout Europe as far east as the Urals and also in the Azores, in Algeria, and in Asia Minor, Armenia, and Syria. It is strongly migratory.

<span class="mw-page-title-main">African armyworm</span> Species of moth

The African armyworm, also called okalombo, kommandowurm, or nutgrass armyworm, is a species of moth of the family Noctuidae. The larvae often exhibit marching behavior when traveling to feeding sites, leading to the common name "armyworm". The caterpillars exhibit density-dependent polyphenism where larvae raised in isolation are green, while those raised in groups are black. These phases are termed solitaria and gregaria, respectively. Gregaria caterpillars are considered very deleterious pests, capable of destroying entire crops in a matter of weeks. The larvae feed on all types of grasses, early stages of cereal crops, sugarcane, and occasionally on coconut. The solitaria caterpillars are less active and undergo much slower development. The species is commonly found in Africa, but can also be seen in Yemen, some Pacific islands, and parts of Australia. African armyworm outbreaks tend to be devastating for farmland and pasture in these areas, with the highest-density outbreaks occurring during the rainy season after periods of prolonged drought. During the long dry seasons ("off-season"), the population densities are very low and no outbreaks are seen.

<span class="mw-page-title-main">Silver Y</span> Species of moth

The silver Y is a migratory moth of the family Noctuidae which is named for the silvery Y-shaped mark on each of its forewings.

<i>Agrochola lota</i> Species of moth

Agrochola lota, the red-line Quaker, is a moth of the family Noctuidae. The species was first described by Carl Alexander Clerck in 1759. It is distributed throughout the whole of Europe except Scandinavia; in Armenia, Asia Minor, and east across the Palearctic to the Altai mountains and western Siberia.It was introduced to Newfoundland. In the Alps, it rises at altitudes of just over 1500 metres.

<i>Ceramica pisi</i> Species of moth

The Broom Moth(Ceramica pisi) is a moth of the family Noctuidae. It is found in all of Europe, East across the Palearctic to Siberia and the Russian Far East. In the north, it is found far beyond the Arctic Circle and in the south to northern Spain. In the Alps, it is found at heights of up to 2,000 metres.

<i>Caradrina clavipalpis</i> Species of moth

Caradrina clavipalpis, the pale mottled willow, is a moth of the family Noctuidae. The species was first described by Giovanni Antonio Scopoli in his 1763 Entomologia Carniolica. It is found in the Palearctic realm. It is an introduced species in North America, where it was first reported from Queens in New York City in 1993. In 2009 it was found in Rochester, New York, so it appears to be established and spreading.

<i>Pyrrhia umbra</i> Species of moth

Pyrrhia umbra, the bordered sallow, is a moth of the family Noctuidae. The species was first described by Johann Siegfried Hufnagel in 1766. It is found in all of Europe, east through Anatolia to Iran, Afghanistan, Pakistan and Nepal and through central Asia to Japan. In mountains it can be found up to elevations of 1,600 meters.

<i>Earias clorana</i> Species of moth

Earias clorana, the cream-bordered green pea, is a moth of the family Nolidae. It is found in most of Europe eastwards across the Palearctic to the Urals and Western Siberia.

<i>Agrochola macilenta</i> Species of moth

Agrochola macilenta, the yellow-line Quaker, is a moth of the family Noctuidae. The species was first described by Jacob Hübner in 1809. It is found in Europe and in Asia Minor.

<i>Agrotis cinerea</i> Species of moth

Agrotis cinerea, the light feathered rustic, is a moth of the family Noctuidae. The species was first described by Michael Denis and Ignaz Schiffermüller in 1775. It is found in southern and central Europe, northern Turkey, the Caucasus, western Turkmenia and Central Asia.

<i>Agrotis ripae</i> Species of moth

Agrotis ripae, the sand dart, is a moth of the family Noctuidae. The species was first described by Jacob Hübner in 1823. It is found in western Europe and North Africa and extends east across the Palearctic to steppe areas in Russia, Mongolia and Siberia.

<i>Agrotis trux</i> Species of moth

Agrotis trux, the crescent dart, is a moth of the family Noctuidae. The species was first described by Jacob Hübner in 1824. It has a circum-Mediterranean distribution and is found along the coasts of France, Ireland, England, southern Europe, Algeria, Syria, Iraq, Iran, southern Russia and the Arabian Peninsula. In Africa, it is found as far south as South Africa.

<span class="mw-page-title-main">Flame brocade</span> Species of moth

The flame brocade is a moth of the family Noctuidae. The nominate subspecies T. f. flammea is found in Europe, mostly in the Mediterranean area up to Normandy. It is also found on the Channel Islands and it has spread to Southern England and Ireland. It is found in the Maghreb as the subspecies T. f. vividior. This also occurs in parts of Spain. The species lives primarily in dry areas, on warm slopes, grassy scrubland and in karstic oak.

<i>Hyppa rectilinea</i> Species of moth

Hyppa rectilinea, the Saxon, is a moth of the family Noctuidae. It is found in Europe, but mostly in northern and central Europe. In the south, it is found in scattered populations, mainly in mountainous areas. To the east, its range stretches through northern Asia and eastern Siberia, up to the Pacific Ocean and Japan.

<i>Apamea anceps</i> Species of moth

Apamea anceps, the large nutmeg, is a moth of the family Noctuidae. The species was first described by Michael Denis and Ignaz Schiffermüller in 1775.

<i>Egira conspicillaris</i> Species of moth

Egira conspicillaris, the silver cloud, is a moth of the family Noctuidae. The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. It is found from the Iberian Peninsula to Russia. In the north it ranges to the Baltic Region and in the south to North Africa. It is also present in the Near East, up to the Caspian Sea.

<i>Parastichtis suspecta</i> Species of moth

Parastichtis suspecta, the suspected, is a species of moth in the family Noctuidae. It is found from most of Europe through Russia and east through the Palearctic to Japan. It is also found in North America.

References

  1. ↑ "Spodoptera exigua (Hübner)". ICAR-National Bureau of Agricultural Insect Resources. Retrieved 3 August 2016.
  2. ↑ "beet armyworm (Spodoptera exigua)". Plantwise Technical Factsheet. Retrieved 3 August 2016.
  3. 1 2 3 4 5 "beet armyworm". University of Florida. Retrieved 3 August 2016.
  4. ↑ Hampson, G. F. (1894). The Fauna of British India, Including Ceylon and Burma: Moths Volume II. Vol. Moths - Vol. II. Taylor and Francis – via Biodiversity Heritage Library.
  5. ↑ Seitz, A. Ed., 1914 Die Großschmetterlinge der Erde, Verlag Alfred Kernen, Stuttgart Band 3: Abt. 1, Die Großschmetterlinge des palaearktischen Faunengebietes, Die palaearktischen eulenartigen Nachtfalter, 1914
  6. ↑ Robinson, Gaden S.; Ackery, Phillip R.; Kitching, Ian; Beccaloni, George W.; Hernández, Luis M. (2023). "Robinson, G. S., P. R. Ackery, I. J. Kitching, G. W. Beccaloni & L. M. Hernández, 2010. HOSTS – A Database of the World's Lepidopteran Hostplants. Natural History Museum, London". Natural History Museum. doi:10.5519/havt50xw.{{cite journal}}: Cite journal requires |journal= (help)
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.