Spodoptera eridania
(southern armyworm)

Pictures

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Identity

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Preferred Scientific Name

• Spodoptera eridania Stoll in Cramer

Preferred Common Name

• southern armyworm

Other Scientific Names

• Laphygma eridania (Stoll)
• Noctua eridania Stoll
• Prodenia eridania (Stoll)
• Prodenia externa (Walker)
• Prodenia nigrofascia (Hulst)
• Prodenia xylomiges Cramer
• Spodoptera amygia (Guenée)
• Spodoptera bipunctata (Walker)
• Spodoptera derupta (Morrison)
• Spodoptera externa (Walker)
• Spodoptera ignobilis (Butler)
• Spodoptera inquieta (Walker)
• Spodoptera linea (Fabricius)
• Spodoptera nigrofascia (Hulst)
• Spodoptera phytolaccae (J.E. Smith)
• Spodoptera putrida (Guenée)
• Spodoptera recondita (Möschler)
• Spodoptera strigifera (Walker)
• Xylomyges eridania (Stoll)
• Xylomyges eridania (Stoll)

International Common Names

• English: armyworm, semitropical; armyworm, southern; semi-tropical armyworm
• Spanish: gusano cortador (el salvador); gusano negro; gusano soldado sureño; rosquilla

EPPO code

• PRODER (Spodoptera eridania)

Taxonomic Tree

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• Domain: Eukaryota
•     Kingdom: Metazoa
•         Phylum: Arthropoda
•             Subphylum: Uniramia
•                 Class: Insecta
•                     Order: Lepidoptera
•                         Family: Noctuidae
•                             Genus: Spodoptera
•                                 Species: Spodoptera eridania

Notes on Taxonomy and Nomenclature

Top of page A complete list of synonyms is provided by Todd and Poole (1980). Spodoptera peruviana (Walker) (syn. Laphygma communicata Walker) was synonymized with S. eridania by Todd and Poole (1980). However, it is currently considered once again to be a separate species (Poole, 1989).

Description

Top of page Eggs

Subspherical in shape, laid in large groups on the plant foliage; covered with a layer of grey bristles (scales) derived from the abdomen of the female.

Larvae

There are usually six instars. Fully grown caterpillars measure 35-40 mm. Young larvae are black with yellow lateral lines, but older instars are grey-brown with a dorsal row of paired black triangular spots, and subdorsal reddish lines when older; the head capsule is yellow-brown. Larvae are characterized by a prominent yellow subspiracular line which is broken by a dark (sometimes diffuse) spot on the first abdominal segment (Levy and Habeck, 1976). A full description of the larvae is given in Crumb (1956).

Pupae

A typical noctuid pupa, measuring 16-20 mm long with rounded head and abdomen. Shiny mahogany brown, with darker head, spiracles and anterior edges of abdominal segments. Anal segment terminates in a two-spined cremaster.

Adult

A sturdy grey-brown moth, wing-span 28-40 mm, forewings grey, hindwings pearly-white above with a stronger lustre below. Markings variable, some individuals have a strongly marked reniform spot or bar on the forewing, a very prominent blackish posterior marginal line and a similar black line on the lateral posterior margin. Others have a straight, broad, jet-black band from the mid forewing to the lateral margin. Abdomen brownish-grey and antennae yellowish-brown. The posterior angle of the forewing is narrowly divided from the rest of the wing by an irregular, oblique, pale band. The principal definitive features are in the male genitalia (Todd and Poole, 1980).

Distribution

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S. eridania occurs throughout southern USA, Central and South America, and the Caribbean. Although it is not established in Europe, S. eridania is commonly recorded as an accidental introduction from the New World, for example, in Denmark (Karsholt, 1994).

The distribution map incudes records based on specimens of S. eridania from the collection in the Natural History Museum (BMNH, London, UK).

A record of S. eridania in Guernsey (CABI/EPPO, 2006) published in previous versions of the Compendium was erroneous. Guernsey is not included in the list of countries for S. eridania in CABI/EPPO (2006).

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Risk of Introduction

Top of page S. eridania is now classed as an EPPO A1 list of quarantine pests, but it is not listed as a quarantine pest by any other regional plant protection organization. As a subtropical species, it is most likely to become established in southern Europe. In the New World it is not especially recorded as a glasshouse pest,
but it could become so in Europe. S. eridania occurs very regularly in Europe on imported plant produce from the New World, and it has been found on tomatoes and other local plants in the UK (Seymour, 1978).

Hosts/Species Affected

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S. eridania is a polyphagous generalist feeder recorded on a wide range of plant species including many grasses and dicotyledonous species. Crops damaged include aubergines, species of Beta and Capsicum, cassava, cotton, several members of the Brassicaceae, a wide range of legumes, maize and other Poaceae, potatoes, sweet potatoes, tobacco, tomatoes, yams, and many pot plants and vegetables. Montezano et al. (2014) lists more than 200 natural hosts plants of S. eridania.

Many potential crop hosts are available in Europe, especially those more commonly grown in the southern part of the region. Sugarbeet and field tomatoes could be especially vulnerable, as well as a wide range of vegetables and flowers, including those grown in glasshouses.

Host Plants and Other Plants Affected

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Growth Stages

Top of page Fruiting stage, Vegetative growing stage

Symptoms

Top of page Leaf-eating and skeletonization is the main damage to the host plant, and in extreme cases complete defoliation may occur. Larvae are not normally observed because they are nocturnal feeders, but the first two instars are gregarious and can be seen in clusters on the foliage. Holes may be observed on tomato fruits and large larvae sometimes act as cutworms.

List of Symptoms/Signs

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Biology and Ecology

Top of page Eggs are laid in large batches on the leaves of the host plant, protected by a layer of grey bristles from the female abdomen. Development usually takes 4-8 days. Larvae, as with some other Noctuidae, are gregarious and remain together on the leaf for the first two instars, resulting in leaf skeletonization. The third-instar larvae disperse and become more solitary and nocturnal. During the day they hide in the leaf litter or plant foliage, and emerge to feed on the leaves at night. Larval development usually takes 14-18 days. As with other Noctuidae, the rate of larval development is affected by the quality of diet and prevailing temperatures; the latter also affects the adult condition. Larvae sometimes swarm and migrate to adjacent fields when food is scarce. Occasionally, large larvae have been recorded acting as cutworms.

Pupation takes place in the soil in a weak earthen cell and typically requires 9-12 days. Adults are nocturnal in habit.

S. eridania is essentially a subtropical species and so a temperature of 20-25°C is optimum for development, and breeding may be continuous. The life cycle can be completed in 28-30 days, but up to 40 days is common. There are several to many generations per year, the number depending on local conditions. Experiments in Brazil by Foerster & Dionizio (1989) showed that development at temperatures of 17 (115 days) and 30°C (33 days) was retarded. At 30°C, pupae weighed less and survival rates were lower.

The sex pheromone produced by female moths has been described, comprising of (Z)-9-tetradecenyl acetate (59.7%), (Z,E)-9,12-tetradecadienyl acetate (23.8%), (Z)-9-tetradecenol (8.4%), (Z)-11-hexadecenyl acetate (5.1%), (Z,Z)-9,12-tetradecadienyl acetate (3%) and (Z,E)-9,11-tetradecadienyl acetate (trace).

Means of movement and dispersal

In the New World, S. eridania does not engage in long-distance migrations, so it would be most unlikely to make a transatlantic crossing as a flying adult. It is not known how the infestation of the Galapagos Islands occurred, but it might have been by flying moths. The frequent European records are usually of intercepted larvae on the foliage of infested host plants (Seymour, 1978), but occasionally in the UK and other parts of Europe, larvae are found on plants and some adult moths are found in light traps.

Natural enemies

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Notes on Natural Enemies

Top of page Natural control by parasitic Hymenoptera and Tachinidae is of importance in the field. King and Saunders (1984) list important species on Caribbean Islands. Biological control was attempted on a number of Commonwealth Caribbean islands, resulting in the establishment of Telenomus remus (Cock, 1985).

Impact

Top of page S. eridania is usually only a minor pest on most crops in the New World, but occasionally serious infestations occur. It is most damaging on tomato fruits and sweet potatoes, although many vegetables and flowers can be seriously locally affected on occasions. Since most damage is caused by leaf-eating, light infestations on field crops can be tolerated and ignored, but on tomatoes and ornamentals, control may more often be required.

S. eridania larvae have also been recorded as occasional pests of cotton, amaranth and lucerne.

Similarities to Other Species/Conditions

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Adults of S. eridania can be confused with some European Hadeninae and Cuculliinae, especially some species of Cucullia, but these latter moths usually do not have hindwings with translucent white colouration. The forewing margin of S. eridania is also squarer and less oblique than those of Cuculliinae, which have more slender, elongate and pointed wings than species of Spodoptera.

An EPPO standard provides guidance for the identification of S. littoralis, S. litura, S. frugiperda and S. eridania (OEPP/EPPO, 2015).

Prevention and Control

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Chemical Control

Since S. eridania is often only a minor pest, control is only occasionally required. Insecticidal sprays are the usual means of killing the larvae on the plant foliage when damage is seen. Insecticides recommended for Helicoverpa control can be used for S. eridania: suitable chemicals are listed by COPR (1983) and King and Saunders (1984).

Phytosanitary measures

Plants used for production should come from locations found free from the pest during the previous 3 months. Certain types of plants (for example, cuttings) may be treated by being held at low temperatures <1.7°C) for 2-4 days, followed by fumigation.

References

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CABI/EPPO, 1998. Distribution maps of quarantine pests for Europe (edited by Smith IM, Charles LMF). Wallingford, UK: CAB International, xviii + 768 pp

CABI/EPPO, 2006. Spodoptera eridania. Distribution Maps of Plant Pests, No. 685. Wallingford, UK: CAB International

Cock MJW (ed.), 1985. A review of biological control of pests in the Commonwealth Caribbean and Bermuda up to 1982. Farnham Royal, United Kingdom; Commonwealth Agricultural Bureaux, xii + 218 pp.

COPR, 1983. Pest Control in Tropical Tomatoes. London, UK: COPR

Crumb SE, 1956. The Larvae of the Phalaenidae. Technical Bulletin No. 1135. Washington DC, USA: United States Department of Agriculture

Dias Nda S, Micheletti SMFB, Tourinho Lde L, Rodrigues Vde M, 2009. First record of Spodoptera spp. (Lepidoptera: Noctuidae) attacking Crotalária spp. in Alagoas State, Brazil. (Primeiro registro de ocorrência de Spodoptera spp. (Lepidoptera: Noctuidae) atacando Crotalária no estado de Alagoas, Brasil.) Caatinga, 22(1):1-8. http://periodicos.ufersa.edu.br/index.php/sistema/article/view/842/529

EPPO, 2018. EPPO Global Database. Paris, France: EPPO. https://gd.eppo.int/

Foerster LA, Dionizio ALM, 1989. Temperature requirements for the development of Spodoptera eridania (Cramer, 1782) (Lepidoptera: Noctuidae) on Mimosa scabrella Bentham (Leguminosp). Anais da Sociedade Entomologica do Brasil, 18(1):145-154

Goergen, G., 2018. New alien invasive pest identified in West and Central Africa!. In: IITA Factsheet . Cotonou, Benin: IITA.http://www.iita.org/wp-content/uploads/2018/05/SAW_factsheet-22-May-2018.pdf

Karsholt O, 1994. Some moths introduced into Denmark, with remarks on this subject (Lepidoptera). Entomologiske Meddelelser, 62(1):1-6

King ABS, Saunders JL, 1984. The invertebrate pests of annual food crops in Central America. A guide to their recognition and control. London, UK: Overseas Development Administration

Levy R, Habeck DH, 1976. Descriptions of the larvae of Spodoptera sunia and S. latifascia with a key to the mature Spodoptera larvae of the eastern United States (Lepidoptera: Noctuidae). Annals of the Entomological Society of America, 69(4):585-588

Meagher RL, Brambila J, Hung E, 2008. Monitoring for exotic Spodoptera species (Lepidoptera: Noctuidae) in Florida. Florida Entomologist, 91(4):517-522. http://www.fcla.edu/FlaEnt/

Montezano, D. G., Specht, A., Sosa-Gomez, D. R., Roque-Specht, V. F., Monteiro de Barros, N., 2014. Immature Stages of Spodoptera eridania (Lepidoptera: Noctuidae): Developmental Parameters and Host Plants. Journal of Insect Science, 14(238), doi: 10.1093/jisesa/ieu100

OEPP/EPPO, 2015. EPPO Standards PM 7/124(1) Diagnostic protocol for Spodoptera littoralis, Spodoptera litura, Spodoptera frugiperda, Spodoptera eridania. Bulletin OEPP/EPPO Bulletin, 34:257-270

Seymour PR, ed. , 1978. Insects and other invertebrates intercepted in check inspections of imported plant material in England and Wales during 1976 and 1977. Insects and other invertebrates intercepted in check inspections of imported plant material in England and Wales during 1976 and 1977. Plant Pathology Laboratory. Harpenden, Herts. UK, [2+] 54 pp

Todd EL, Poole RW, 1980. Keys and illustrations for the armyworm moths of the noctuid genus Spodoptera Guenee from the Western Hemisphere. Annals of the Entomological Society of America, 73(6):722-738

Distribution Maps

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