Preferred name: Spodoptera eridania
Authority: (Stoll)
Taxonomic position: Animalia: Arthropoda: Hexapoda: Insecta: Lepidoptera: Noctuidae
Other scientific names: Laphygma eridania (Stoll), Phalaena eridania Stoll, Prodenia eridania (Stoll), Xylomyges eridania (Stoll)
Common names in English: semitropical armyworm, southern armyworm
view more common names online...
Notes on taxonomy and nomenclature EPPO Categorization: A1 list
EU Categorization: A1 Quarantine pest (Annex II A)
view more categorizations online...
EPPO Code: PRODER

Spodoptera eridania is a polyphagous generalist feeder recorded on 202 different wild hosts and crops, including many grasses and dicotyledonous plants (Montezano et al., 2014). Crops damaged include aubergine, beets (Beta vulgaris vulgaris var. altissima, and var. cicla), sweet pepper (Capsicum annuum), cassava, cotton, several Brassicaceae, a wide range of legumes, maize and other Poaceae, potatoes, sweet potatoes, tobacco, tomatoes, yams, and many ornamental pot plants and species intended for the cut flower market.

The EPPO region is home to numerous potential host plants and especially the south of the region grows many crop host species (Montezano & Specht, 2022).

Host list: Abelmoschus esculentus, Acaciella glauca, Achyranthes aspera, Alcea rosea, Allium cepa, Allium fistulosum, Allium sativum, Alpinia purpurata, Amaranthus deflexus, Amaranthus hybridus, Amaranthus quitensis, Amaranthus retroflexus, Amaranthus spinosus, Amaranthus viridis, Antirrhinum majus, Apium graveolens, Arachis hypogaea, Artemisia absinthium, Asparagus officinalis, Baccharis genistelloides, Bacopa stricta, Begonia rex, Beta vulgaris subsp. vulgaris var. cicla, Beta vulgaris, Bidens pilosa, Brassica napus, Brassica nigra, Brassica oleracea var. capitata, Brassica oleracea var. viridis, Camellia japonica, Capsicum annuum, Carica papaya, Cayaponia americana, Cayaponia racemosa, Cecropia peltata, Celosia argentea, Cenchrus purpureus, Centrosema pubescens, Cestrum macrophyllum, Chenopodium quinoa, Chrysanthemum x morifolium, Cicer arietinum, Citharexylum spinosum, Citrullus lanatus, Citrus maxima, Citrus x aurantium var. sinensis, Citrus x limon, Clibadium erosum, Clidemia eggersii, Coffea arabica, Commelina diffusa, Crotalaria breviflora, Crotalaria spectabilis, Cucumis melo, Cucumis sativus, Cucurbita maxima, Cynodon nlemfuensis, Daucus carota, Desmodium adscendens, Dianthus caryophyllus, Digitaria ischaemum, Digitaria sanguinalis, Dioscorea polygonoides, Eclipta prostrata, Elaphoglossum sp., Erechtites valerianifolius, Erigeron bonariensis, Erigeron canadensis, Eruca vesicaria subsp. sativa, Eucalyptus sp., Fragaria vesca, Geranium sp., Gerbera jamesonii, Glycine max, Gonzalagunia spicata, Gossypium herbaceum, Gossypium hirsutum, Hamelia patens, Helianthus annuus, Helianthus sp., Hibiscus cannabinus, Hibiscus rosa-sinensis, Hydrocotyle ranunculoides, Ichnanthus pallens, Impatiens walleriana, Ipomoea alba, Ipomoea batatas, Ipomoea fastigiata, Ipomoea grandiflora, Ipomoea purpurea, Lactuca sativa, Lagerstroemia indica, Laportea aestuans, Lavandula angustifolia, Lepidium didymum, Linum usitatissimum, Lobelia portoricensis, Lolium perenne, Lonicera japonica, Ludwigia sp., Malus domestica, Malva parviflora, Manihot esculenta, Medicago sativa, Melinis minutiflora, Melissa officinalis, Mentha arvensis var. piperascens, Mentha sp., Mentha spicata, Mentha x piperita, Mikania cordifolia, Mimosa pudica, Mimosa scabrella, Morus alba, Mucuna pruriens, Nasturtium officinale, Nerium oleander, Neurolaena lobata, Nicotiana alata, Nicotiana tabacum, Ocotea sp., Odontonema tubaeforme, Oryza sativa, Passiflora edulis, Passiflora sexiflora, Pavonia fruticosa, Pelargonium x hortorum, Pentas sp., Persea americana, Persicaria hydropiperoides, Persicaria segetum, Phaseolus lunatus, Phaseolus polystachyus, Phaseolus vulgaris, Phyllanthus urinaria, Phytolacca americana, Phytolacca dioica, Phytolacca rigida, Phytolacca rivinoides, Piper umbellatum, Pisum sativum, Plantago major, Portulaca grandiflora, Portulaca oleracea, Pseudelephantopus spicatus, Psidium guajava, Psychotria berteroana, Pyrus communis, Rajania cordata, Rheum rhabarbarum, Ricinus communis, Rosa sp., Rubus idaeus, Rubus rosifolius, Rumex crispus, Rumex obtusifolius, Rumex sp., Salix sp., Sanchezia speciosa, Sanguinaria canadensis, Sapium glandulosum, Sauvagesia erecta, Schefflera morototoni, Schinus terebinthifolia, Sechium edule, Sida rhombifolia, Solanum acerifolium, Solanum americanum, Solanum jamaicense, Solanum lycopersicum, Solanum melongena, Solanum peruvianum, Solanum rugosum, Solanum torvum, Solanum tuberosum subsp. andigenum, Solanum tuberosum, Sonchus oleraceus, Sonchus sp., Spermacoce ocymifolia, Spinacia oleracea, Stenotaphrum secundatum, Taraxacum officinale, Teliostachya alopecuroidea, Trifolium sp., Tripogandra serrulata, Urera baccifera, Vaccinium macrocarpon, Vernicia fordii, Vernonanthura tweedieana, Vicia faba, Vigna unguiculata, Viola tricolor, Vitis labrusca, Vitis vinifera, Xanthosoma sp., Zea mays

S. eridania occurs throughout most tropical and subtropical countries in South and Central America, as well as Southern USA and the Caribbean Islands. It is thought to originate in these areas of the Americas. The species also occurs on the Galápagos Islands where it was most likely introduced. S. eridania was first discovered across the Atlantic Ocean in Nigeria, 2016, as a pest in cassava, and later in Benin, Cameroon and Gabon. It is unclear when S. eridania first appeared on the African continent as it is easily confused with other Spodoptera species already present (Goergen, 2018). The species is also reported from India where it was found on soybean in 2019. However, it was no longer found in the area in 2020 and 2021 (Gaikwad, 2021).

Africa: Benin, Cameroon, Gabon, Nigeria
Asia: India (Maharashtra)
North America: Mexico, United States of America (Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Maryland, Mississippi, New Hampshire, North Carolina, Ohio, Oklahoma, South Carolina, Tennessee, Texas, Virginia, West Virginia)
Central America and Caribbean: Antigua and Barbuda, Bahamas, Barbados, Bermuda, Costa Rica, Cuba, Dominica, Dominican Republic, El Salvador, Grenada, Guadeloupe, Honduras, Jamaica, Martinique, Nicaragua, Panama, Puerto Rico, Saint Lucia, St Vincent and the Grenadines, Trinidad and Tobago
South America: Argentina, Brazil (Alagoas, Espirito Santo, Goias, Mato Grosso, Mato Grosso do Sul, Minas Gerais, Para, Parana, Rio Grande do Sul, Santa Catarina, Sao Paulo), Chile, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname, Uruguay, Venezuela

Eggs are laid in large batches on the leaves of the host plant, protected by a layer of abdominal bristles. Eggs hatch usually within 4 to 8 days, depending on climatic conditions. Eggs do not develop at temperatures above 34°C. Larvae, like those of sibling species and some other noctuids, are gregarious and remain together on the leaf for the first two instars. The result of this early larval damage is typically the complete skeletonization of leaves. The third instar larvae disperse and become more solitary and nocturnal. During the day caterpillars hide in the leaf litter or plant foliage, and emerge to feed on the leaves at night. Larval development usually takes 14-18 days but the developmental and survival rates of larvae are affected by the quality of the diet and prevailing temperatures. Caterpillars can sometimes swarm and migrate to adjacent fields when food is scarce, hence the common name ‘armyworm’. Occasionally large larvae have been recorded boring into and feeding on fruits, tubers and young stems. Larvae go through six instars, rarely seven, before digging down in the soil near the host plant. Pupation takes place at a depth of 5–10 cm in an earthen cell and pupal development typically takes 9–12 days at 25°C and 70% RH. Adults are nocturnal.

S. eridania is essentially a subtropical species and so a development temperature of 20–25°C is preferred. The total generation time is estimated to be around one month but the time needed to complete a life cycle, as well as larval survivability, depends on the host plant and temperature (Sampaio et al., 2021; Silva et al., 2018). Individuals raised on clover leaves completed their life cycle in 30 days and had a viability of 54.3% whereas only 23% of the individuals fed apple leaves survived and needed 63 days to complete development (Silva et al., 2018). Under laboratory conditions, S. eridania fails to complete its life cycle at temperatures below 15°C and above 32°C with development times at both extremes differing by 95 days (120.1 days at 15°C to 24.6 days at 32°C) (Sampaio et al., 2021). The species does not diapause. Consequently, under favourable local conditions (of which temperature and food availability are most important), development continues throughout the year, resulting in continuous generations (e.g. see Mitchell & Tumlinson, 1994). As the species is highly polyphagous, it is easy to rear, and as a result the species is used in many feeding experiments detailing the response of the larvae to different plant species and pest control agents such as Bacillus thuringiensis (Bt) (e.g. see Rabelo et al., 2020; Scriber, 1981; Silva et al., 2017).

Symptoms

Larvae mainly cause damage to leaves, which usually results in skeletonization or can lead to complete defoliation in extreme cases. The first two instars are gregarious and diurnal and are thus relatively easily observed as clusters of small caterpillars on leaves. Large larvae may bore into some fruits (such as tomato) or cotton bolls. When there is a lack of adequate leaf material, larvae may feed on small apical branches, bore into the stem of the host plant or attack tubers that are close to the soil surface.

Morphology

Eggs

Subspherical in shape, 0.45 mm in diameter, laid in clusters on the plant foliage, usually covered with a layer of grey bristles (scales) from the abdomen of the female. Like in other Spodoptera species, the number of ribs on the eggs varies widely (between 46–54 according to Rolim et al., 2013), with too much overlap between species to allow for reliable identification beyond genus level. The micropyllar rosette is flat. Eggs are greenish at first and become tan as they develop.

Larva

There are usually six instars. First instar larvae are 1–2.5 mm long, fully grown caterpillars measure 35–40 mm. Young larvae are black with yellow lateral lines and look similar to other Spodoptera species. During early development, the first dorsal pinacula on abdominal segments 1 and 8 become larger and darker. Older instars have a variable ground colour, generally rather grey to greenish-grey, but a brown larval form also exists. Later-stage larvae have a reddish-brown head capsule with a Y-shaped-marking and longitudinal bands made up of black, white and red. Fully grown larvae have a dark lateral spot on the first abdominal segment, which passes through and breaks up, the yellowish spiracular line. The larva usually has a dorsal row of paired dark, often triangular patches, the ones on abdominal segments 1 and 8 always being the largest.

Pupa

A typical noctuid pupa, shiny brown, and 19-20 mm long, cremaster with two small spines. This trait is shared with at least S. littoralis, S. litura and S. frugiperda. Spodoptera exigua has an extra pair of smaller spines anterodorsally of the cremaster. The spines that make up the cremaster are variable in size, fragile and prone to breakage.

Adult

Moth with a wingspan of 28-40 mm. The forewings are cream to grey with a characteristic dark streak near the wing base and sometimes a central dark spot or bar. The hindwings are white with no contrasting veins. Several Spodoptera species are hard to distinguish from S. eridania based on external morphological features. Dissection of the male genitalia allows for distinction between S. eridania and other common Spodoptera pests. Male and female genitalia of S. eridania and closely related species are described in the EPPO Standard PM 7/124(1) (EPPO, 2015).

For more information on the morphological discrimination between the common Spodoptera pest species and a detailed description of the different stages, see the EPPO Standard PM 7/124 (EPPO, 2015). Pogue (2002) reviews the Spodoptera genus as a whole.

Detection and inspection methods

Trapping adults is an effective method to survey Lepidoptera. The composition of female sex pheromones of S. eridania is described and often used to attract moths to baited sticky traps. Adults are nocturnal and therefore difficult to detect during the day. Eggs and early larval stages can be found on host plants, but may be overlooked. Feeding damage to the leaves is easily detected, and on some occasions fruits, young branches and tubers can show feeding damage. Older larvae become solitary, hide near the host plants in the leaf litter during daytime and feed on leaves during the night. Pupae cannot be detected on the plant since pupation takes place in the soil. Reliable morphological identification of immature stages either requires additional information (e.g. origin and host plant) or molecular analysis (van de Vossenberg & van der Straten, 2014).

S. eridania is not known to engage in long-distance migrations. It is therefore unlikely that the recent introduction to West- and Central Africa is the consequence of an active transatlantic migration by adults. Unlike S. frugiperda, range expansion of S. eridania following its introdution to Africa seems to be slow. Human-assisted dispersal is considered the most likely pathway through which the species can colonize new areas. Eggs and larvae are easily transported with plants for planting or cut flowers, pupae could be transported along with soil. The species is regularly intercepted on imported plants from South and Central America. These interceptions usually comprise larvae or eggs being found on the foliage of host plants.

Economic impact

Usually, S. eridania is only a minor pest on most of its host crops in its native range, but it may occasionally cause serious damage when infestations become large. The species is most notably damaging to tomato (Price & Poe, 1977), sweet potato (Zeddam et al., 1999), alfalfa (Aguilera & Vasquez, 1974) and soybean (Specht et al., 2018) in the Americas including in the Caribbean Islands, sometimes resulting in significant losses. Due to its polyphagous nature many vegetables and flowers can be attacked. Leafy vegetables and ornamentals are especially prone to incur economic losses due to this pest. In Africa, the species caused severe defoliation in cassava fields and it also infested tomato crops (Goergen, 2018). In India, larvae skeletonized soybean leaves and fed on the seed pods (Gaikwad, 2021).

Control

Conventional chemical insecticides are usually effective at controlling S. eridania; the species is not known to have developed strong resistances to foliar insecticides.

There are several studies assessing the effectiveness of alternative pest control methods. Commercially available neem-based biopesticides can induce antifeedant behaviour and result in up to 20% larval mortality but the effectiveness depends on the product and timing of administration (Shannag et al., 2015). Larvae are susceptible to certain Bacillus thuringiensis (Bt) strains, most notably Cry2Aa, whereas they are highly tolerant to Cry1Ac and Cry1Fa (Rabelo et al., 2020). The entomopathogenic fungus Beauveria bassiana has proven somewhat effective in controlling the pest in cabbage (Michereff‐Filho et al., 2008). Wasp parasitoids and tachinid predators, often associated with other Lepidoptera, are also able to control S. eridania populations. Studies on the biological control of egg parasitoids such as Telenomus remus (Pomari et al., 2013) and predators such as Podisus nigrispinus (Romário de Carvalho et al., 2020) also show promise as effective control agents against S. eridania but it is unclear whether these species are already in practice in the field. Alternative methods such as adding sterile (irradiated) adult males to the population, which has been tested on other Spodoptera pests (Seth et al., 2016), might also be effective against S. eridania but studies are needed. Since S. eridania is usually a minor pest, control is only occasionally required.

Phytosanitary risk

As an essentially subtropical species (temperature optima between 20 and 25°C) that cannot withstand extended periods of freezing temperatures, potential establishment outdoors in the EPPO region may be limited to small areas which have a subtropical climate. These regions grow several potential host plants as crops which could sustain the pest. S. eridania is not specifically reported as a pest of protected cultivation in its native range, but it remains unclear whether the species would be able to establish itself in glasshouses in colder climates in the EPPO region. In its introduced range (i.e. in West and Central Africa since 2016 and India in 2019), the larvae caused significant damage to crops. It is unclear whether the presence of other (native) Spodoptera species with similar host plants in those areas could limit the spread of S. eridania. More details on the risk of introduction into the EPPO region can be found in the EFSA Pest Categorization (EFSA, 2020).

The introduction of S. eridania into the EPPO region is to be avoided regardless of the host plant(s) concerned. Import of soil from countries where S. eridania is present is prohibited. The pest can be controlled in the producing country through conventional insecticide treatment or biological pest control. Surveys with pheromone traps and visual inspection for leaf damage could help verify the presence or absence of the pest. Plants for planting, that are potential host plants of S. eridania, should come from a production location that is inspected and found free of the pest for at least 3 months prior to import. Certain types of plants (e.g. cuttings) may be treated by being held at low temperatures (< 1.7°C for 2-4 days, followed by fumigation). More details on potential measures can be found in the EFSA Pest Categorization (EFSA, 2020).

Aguilera P & Vasquez C (1974) Prueba de laboratorio con 30 insecticidas en larvas de Prodenia eridania (Cramer)(Lepidoptera: Noctuidae) en alfalfa. Idesia 3, 133-140 (in Spanish).

Cramer P & Stoll C (1782) De uitlandsche kapellen voorkomende in de drie waereld-deelen, Asia, Africa en America. Chez S. J. Baalde, Amsteldam (in Dutch).

EFSA Panel on Plant Health, Bragard C, Dehnen-Schmutz K, Di Serio F, Gonthier P, Jacques M-A, Jaques Miret JA, Justesen AF, Magnusson CS, Milonas P, Navas-Cortes JA, Parnell S, Potting R, Reignault PL, Thulke H-H, Van der Werf W, Vicent Civera A, Yuen J, Zappalà L, Czwienczek E & MacLeod A (2020) Pest categorisation of Spodoptera eridania. EFSA Journal 18, e05932.

EPPO (2015) EPPO Standards PM 7/124 (1) Diagnostics. Spodoptera littoralis, Spodoptera litura, Spodoptera frugiperda, Spodoptera eridania. EPPO Bulletin 45, 410-444.

Gaikwad SM (2021) First report of Spodoptera eridania (Stoll)(Lepidoptera: Noctuidae) on soybean [Glycine max (L.) Merrill] from Kolhapur, Maharashtra, India. Journal of Entomology and Zoology Studies 9(2), 1419-1422.

Goergen GE (2018) Southern armyworm, a new alien invasive pest identified in west and Central Africa. Crop Protection 112, 371-373. 

Michereff‐Filho M, Torres JB, Andrade LN & Nunes MUC (2008) Effect of some biorational insecticides on Spodoptera eridania in organic cabbage. Pest Management Science: formerly Pesticide Science 64, 761-767.

Mitchell ER & Tumlinson JH (1994) Response of Spodoptera exigua and S. eridania (Lepidoptera: Noctuidae) males to synthetic pheromone and S. exigua females. Florida Entomologist 77(2), 237-247.

Montezano DG & Specht A (2022) Spodoptera eridania (southern armyworm). CABI Compendium. https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.44518

Montezano DG, Specht A, Sosa-Gomez DR, Roque-Specht VF & de Barros NM (2014) Immature stages of Spodoptera eridania (Lepidoptera: Noctuidae): developmental parameters and host plants. Journal of Insect Science 14, 238. https://doi.org/10.1093/jisesa/ieu100

Pogue MG (2002) A world revision of the genus Spodoptera Guenée (Lepidoptera: Noctuidae). American Entomological Society Philadelphia.

Pomari AF, Bueno AF, Bueno RCOF & Menezes AO (2013) Telenomus remus Nixon egg parasitization of three species of Spodoptera under different temperatures. Neotropical Entomology 42, 399-406.

Price JF & Poe S (1977) Influence of stake and mulch culture on lepidopterous pests of tomato. Florida Entomologist 60(3), 173-176.

Rabelo MM, Matos JML, Santos-Amaya OF, França JC, Gonçalves J, Paula-Moraes SV, Guedes RNC & Pereira EJG (2020) Bt-toxin susceptibility and hormesis-like response in the invasive southern armyworm (Spodoptera eridania). Crop Protection 132, 105129.

Rolim AASG, Yano SAC, Specht A, Andrade CGTDJ & Sosa-Gómez DR (2013) Morphological and molecular characterization of the eggs of some noctuid species associated with soybean in Brazil. Annals of the Entomological Society of America 106, 643-651.

Romário de Carvalho J, Pratissoli D, Moreira de Araujo Junior L, Pacheco Damascena A, Mathias Holtz A, Pin Dalvi L & Rodrigues Vianna U (2020) Predation behavior of Podisus nigrispinus on Spodoptera eridania. Journal of Asia-Pacific Entomology 23, 1279-1282.

Sampaio F, Krechemer FS & Marchioro CA (2021) Temperature-dependent development models describing the effects of temperature on the development of Spodoptera eridania. Pest Management Science 77, 919-929.

Scriber JM (1981) Sequential diets, metabolic costs, and growth of Spodoptera eridania (Lepidoptera: Noctuidae) feeding upon dill, lima bean, and cabbage. Oecologia 51, 175-180.

Seth RK, Khan Z, Rao DK & Zarin M (2016) Flight activity and mating behavior of irradiated Spodoptera litura (Lepidoptera: Noctuidae) males and their F1 progeny for use of inherited sterility in pest management approaches. Florida Entomologist 99, 119-130,.

Shannag HK, Capinera JL & Freihat NM (2015) Effects of neem-based insecticides on consumption and utilization of food in larvae of Spodoptera eridania (Lepidoptera: Noctuidae). Journal of Insect Science 15(1), 152. https://doi.org/10.1093/jisesa/iev134 

Silva A, Baronio C, Galzer E, Garcia M & Botton M (2018) Development and reproduction of Spodoptera eridania on natural hosts and artificial diet. Brazilian Journal of Biology 79, 80-86.

Silva DMd, Bueno AdF, Stecca CdS, Andrade K, Neves PMOJ & Oliveira MCNd (2017) Biology of Spodoptera eridania and Spodoptera cosmioides (Lepidoptera: Noctuidae) on Different Host Plants. Florida Entomologist 100, 752-760.

Specht A, Paula-Moraes S, Malaquias J, Ferreira L, Otanásio P & Diniz I (2018) Owlet moths (Lepidoptera: Noctuoidea) associated with Bt and non-Bt soybean in the Brazilian savanna. Brazilian Journal of Biology 79, 248-256.

Stoll C (1780) Natuurlyke en naar 't leeven naauwkeurig gekleurde afbeeldingen en beschryvigen der cicaden en wantzen, in alle vier waerelds deelen Europa, Asia, Africa en America = Représentation exactement colorée d'après nature des cigales et des punaises : qui se trouvent dans les quatre parties du monde, l'Europe, l'Asie, l'Afrique, et l'Amerique. Jan Christiaan Sepp, Amsterdam (in Dutch).

van de Vossenberg BT & van der Straten MJ (2014) Development and validation of real-time PCR tests for the identification of four Spodoptera species: Spodoptera eridania, Spodoptera frugiperda, Spodoptera littoralis, and Spodoptera litura (Lepidoptera: Noctuidae). Journal of Economic Entomology 107, 1643-1654.

Zeddam J-L, Rodriguez JL, Ravallec M & Lagnaoui A (1999) A noda-like virus Isolated from the sweetpotato pest Spodoptera eridania (Cramer) (Lep.; Noctuidae). Journal of Invertebrate Pathology 74, 267-274.

This datasheet was extensively revised in 2023 by Jan E.J. Mertens and Tom H. van Noort of NPPO-NL, their valuable contribution is gratefully acknowledged.

EPPO (2024) Spodoptera eridania. EPPO datasheets on pests recommended for regulation. https://gd.eppo.int (accessed 2024-04-26)

This datasheet was first published in 1997 in the second edition of 'Quarantine Pests for Europe, and revised in 2023. It is now maintained in an electronic format in the EPPO Global Database. The sections on 'Identity', ‘Hosts’, and 'Geographical distribution' are automatically updated from the database. For other sections, the date of last revision is indicated on the right.

CABI/EPPO (1997) Quarantine Pests for Europe (2^nd edition). CABI, Wallingford (GB).