Classification

Noctuoidea: Noctuidae: Noctuinae: Spodoptera littoralis (Boisduval)

Common name

Egyptian cottonworm, African cotton leaf worm, Mediterranean brocade moth, Egyptian cotton leaf worm

Synonyms

Prodenia littoralis, Hadena retina, Prodenia testaceoides

Larval diagnosis (Detailed)

The larvalarva:
the stages between the egg and pupa of those insects having complete metamorphosis
of S. littoralis, usually called the Egyptian Cottonworm (USDA 1982), was at least partially described by Weisman (1974)Weisman (1974):
Weisman, D. M. 1974. Some lepidopterous larvae of plant quarantine significance. U. S. Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine unpublished training aid. 22 pp., Brown and Dewhurst (1975)Brown and Dewhurst (1975):
Brown, E. S. and C. F. Dewhurst. 1975. The genus Spodoptera (Lepidoptera, Noctuidae) in Africa and the Near East. Bulletin of Entomological Research 65: 221-262., Sannino and Espinosa (1999)Sannino and Espinosa (1999):
Sannino, L. and B. Espinosa. 1999. Morphological notes on Mamestra brassicae (Lepidoptera: Noctuidae). Il Tabacco 7: 13-24., Amate et al. (1998, Beck (1999-2000), Gomez de Aizpurua (1987, 2002), Pogue (2002)Pogue (2002):
Pogue, M. G. 2002. A world revision of the genus Spodoptera Guenee (Lepidoptera: Noctuidae). Memoirs of the American Entomological Society 43. 202 pages., Ahola and Silvonen [2008], and Passoa (2011)Passoa (2011):
Passoa, S. 2011. Field key to late instars of Spodoptera of America North of Mexico, pp. 386-387. In Wagner, D. L., D. F. Schweitzer, J. Bolling Sullivan and R. C. Reardon. Owlet caterpillars of eastern North America. Princeton University Press.. Color illustrations of S. littoralis were published by Porter (1997)Porter (1997):
Porter, J. 1997. The Colour Identification Guide to Caterpillars of the British Isles. Viking Press London. 275 pp., Beck (1999-2000), Gomez de Aizpurua (1987, 2002), Ahola and Silvonen [2008], and Wagner et al. (2011)Wagner et al. (2011):
Wagner, D. L., D. F. Schweitzer, J. B. Sullivan and R. C. Reardon. 2011. Owlet caterpillars of eastern North America. Princeton University Press, New Jersey. 576 pp..

Weisman (1986)Weisman (1986):
Weisman, D. M. 1986. Keys for the identification of some frequently intercepted lepidopterous larvae. U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine series 81-47. 64 pp. did not include S. littoralis in his key. However, this species was studied by Brown and Dewhurst (1975)Brown and Dewhurst (1975):
Brown, E. S. and C. F. Dewhurst. 1975. The genus Spodoptera (Lepidoptera, Noctuidae) in Africa and the Near East. Bulletin of Entomological Research 65: 221-262. in their revision of African Spodoptera. Beck (1999-2000) published a key to the Noctuidae of Europe, whereas Ahola and Silvonen [2008] focused on northern European noctuid species. Both authors included S. littoralis and provided detailed descriptions of the mouthparts. These faunal studies make identification of S. littoralis more accurate than Asian or South American species of Spodoptera assuming the origin is known with certainty and the color pattern is typical. As a result, we do not feel a complete literature review of larval descriptions of S. littoralis is needed, but we do summarize a few of the above publications.

Weisman (1974)Weisman (1974):
Weisman, D. M. 1974. Some lepidopterous larvae of plant quarantine significance. U. S. Department of Agriculture, Animal and Plant Health Inspection Service, Plant Protection and Quarantine unpublished training aid. 22 pp. defined a "Prodenia group" that included S. littoralis and other species of Spodoptera. He mentioned a broad and flat spinneretspinneret:
a structure from which silk is spun, usually located on the labium of larvae
, almost equal in length to the labial palpuslabial palpus:
a pair of small, segmented sensory structures arising on the distolateral portions of the labium
, with a middorsal groove and two small projections at the apex. The SD setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
are off the prothoracic shieldprothoracic shield:
the dorsal shieldlike covering of the first thoracic segment
and SD1 of the mesothoraxmesothorax:
the second thoracic segment
[and metathorax] are connected to the associated tonofibrillary platelettonofibrillary platelet:
a small, external, flattened, sclerotized area of the integument associated with muscle attachment
by a minute sclerotizedsclerotized:
hardened and tanned, so that it is yellow to black in color
bar. The mandible has no retinaculumretinaculum:
a projection or toothlike structure on the oral surface of the mandible
.

Brown and Dewhurst (1975)Brown and Dewhurst (1975):
Brown, E. S. and C. F. Dewhurst. 1975. The genus Spodoptera (Lepidoptera, Noctuidae) in Africa and the Near East. Bulletin of Entomological Research 65: 221-262. separated S. littoralis and S. exigua from other African species by the spacing of the P setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
, relative size of the frontfront:
the frons or frontal area, sometimes including the clypeus
to the epicrania, and the presence of teeth on the mandible (thus a serrateserrate:
sawlike
cutting edge). Other related species of African Spodoptera lacked mandibular teeth and thus the mandible has a smooth cutting edge. This was the easiest character to separate the two groups.

Amate et al. (1998)Amate et al. (1998):
Amate, J., P. Barranco and T. Cabello. 1998. Identificacion de larvas de las principales especies de noctuidos plaga de Espana (Lepidoptera: Noctuidae). Boletin de Sanidad Vegetal 24: 101-106. noted that the prothoracic SD setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
of S. littoralis are in a horizontal line and the abdominal spiracles are brownish with a black border. In their key to tobacco feeding Lepidoptera of Italy, Sannino and Espinosa (1999: 35, plateplate:
a larger sclerotized area of the body; = shield
17) called attention to the pattern of the dorsaldorsal:
at the top or back or above
triangles and the presence of a shieldshield:
a sclerotized plate covering part of the dorsum of a segment
on the abdominal prolegsabdominal prolegs:
all prolegs on any abdominal segment except the last, which are Anal prolegs
.

The world Spodoptera key in Pogue (2002)Pogue (2002):
Pogue, M. G. 2002. A world revision of the genus Spodoptera Guenee (Lepidoptera: Noctuidae). Memoirs of the American Entomological Society 43. 202 pages. defined S. littoralis by the large dorsaldorsal:
at the top or back or above
triangles on A7 and A8, compared to A1-6, and presence of a light spot in the middle of the border between the abdominal dorsaldorsal:
at the top or back or above
and subdorsal areas. Like S. litura, there is a light spot posteriorposterior:
caudal or rear
of the spiracle, although it can be faint. He compared S. exigua to S. littoralis; the former species has a stripe on the prothoracic shieldprothoracic shield:
the dorsal shieldlike covering of the first thoracic segment
lacking in S. littoralis.

Like S. litura, S. littoralis has a rather unspecialized morphology. The genus Spodoptera keys out in the last couplet of Amate et al. (1998)Amate et al. (1998):
Amate, J., P. Barranco and T. Cabello. 1998. Identificacion de larvas de las principales especies de noctuidos plaga de Espana (Lepidoptera: Noctuidae). Boletin de Sanidad Vegetal 24: 101-106., only after all the other species are eliminated. Beck (1999-2000) has made the most progress in emphasizing morphological differences among the taxa. He defined the tribe Prodeniini (Beck 1999-2000: 381) by having a medianmedian:
in the middle
notch at the tip of the tip of the spinneretspinneret:
a structure from which silk is spun, usually located on the labium of larvae
(sometimes with projections) and "peaked fringe" on the upper lip of the silk pore that appears as paired projections or a fringe of spines (Beck 1999-2000: 381, fig. 903a). The head markings are pale and the "AF charact". This likely refers to the pale adfrontal areasadfrontal areas:
an oblique sclerite on each side of the frons, usually extending from the base of the antennae to the epicranial suture where they meet, or to the epicranial notch if they do not meet
forming an inverted "Y" in most of the color forms of Spodoptera (see Wagner et al. 2011Wagner et al. 2011:
Wagner, D. L., D. F. Schweitzer, J. B. Sullivan and R. C. Reardon. 2011. Owlet caterpillars of eastern North America. Princeton University Press, New Jersey. 576 pp.). Beck (1999-2000: 635) then recognized Spodoptera, Laphygma and Prodenia as valid genera, each with a single species. Spodoptera (based on cilium) has bladesblades:
thick flat spines on the proximolateral region of the hypophayngeal complex
("serrula" see Beck 1999-2000Beck 1999-2000:
Beck, H. 1999-2000. Die Larven der Europaischen Noctuidae. Revision der Systematik der Noctuidae (Lepidoptera, Noctuidae). Herbipoliana 5/1(1): 1-864; 5/1(2): 1-448; 5/3(3): 1-512; 5/3(4): 1-336.: fig. 16a) on the hypopharyngeal complexhypopharyngeal complex:
a structure consisting of the Hypopharynx, Labial palpi, and Spinneret
. These are lacking in Spodoptera (Laphygma) exigua and Spodoptera (Prodenia) littoralis. Aside from differences in coloration, separation of Laphygma and Prodenia involves the position of the SV setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
and crochet number. Ahola and Silvonen [2008: 30, 31] used these same characters, but they called the bladesblades:
thick flat spines on the proximolateral region of the hypophayngeal complex
"laterallateral:
to the side, or at the side of
teeth" and placed all three European species in Spodoptera. This character set has not been tested outside the European fauna but Crumb (1929:21) and Passoa (1991)Passoa (1991):
Passoa, S. 1991. Color identification of economically important Spodoptera larvae in Honduras. Insecta Mundi 5(3-4): 185-196. did show blunt bladesblades:
thick flat spines on the proximolateral region of the hypophayngeal complex
without teeth on the hypopharyngeal complexhypopharyngeal complex:
a structure consisting of the Hypopharynx, Labial palpi, and Spinneret
of some North American Spodoptera. Our illustration of the hypophargngeal complex of S. littoralis shows four broad blunt bladesblades:
thick flat spines on the proximolateral region of the hypophayngeal complex
when examined in laterallateral:
to the side, or at the side of
view. The exact distribution of the bladesblades:
thick flat spines on the proximolateral region of the hypophayngeal complex
in Spodoptera has not been documented, but this character has promise for identification of species or at least recognition of the genus.

From the above studies, and those related to S. exigua and S. litura, we suggest the following morphological characters to recognize Spodoptera: head with an inverted "Y" because the adfrontal areasadfrontal areas:
an oblique sclerite on each side of the frons, usually extending from the base of the antennae to the epicranial suture where they meet, or to the epicranial notch if they do not meet
are outlined in white; spinneretspinneret:
a structure from which silk is spun, usually located on the labium of larvae
with a medianmedian:
in the middle
notch and often projections at the silk pore; mandible with four scissorial teeth and no retinaculumretinaculum:
a projection or toothlike structure on the oral surface of the mandible
; SD1 on T2 and T3 connected to the associated tonofibrillary platelettonofibrillary platelet:
a small, external, flattened, sclerotized area of the integument associated with muscle attachment
by a minute sclerotizedsclerotized:
hardened and tanned, so that it is yellow to black in color
bar; SV group bisetosebisetose:
two setae
on A1; SD1 dorsaddorsad:
toward the top or back
of the spiracle on A8; and the body setaeseta:
a hairlike projection of the body wall that is articulated in a socket; compare to spine
short, most not much longer than the vertical height of the spiracle on A8. Passoa (1991)Passoa (1991):
Passoa, S. 1991. Color identification of economically important Spodoptera larvae in Honduras. Insecta Mundi 5(3-4): 185-196. listed nine general characters to separate Spodoptera from other economic noctuids in Honduras, a few of these not mentioned above are applicable to S. littoralis, for example, four [pairs of] abdominal prolegsabdominal prolegs:
all prolegs on any abdominal segment except the last, which are Anal prolegs
present (larvalarva:
the stages between the egg and pupa of those insects having complete metamorphosis
not a looperlooper:
a caterpillar with some prolegs reduced or missing, usually on segments A3-5 (Geometridae) or A3-4 (Noctuidae)
), laterallateral:
to the side, or at the side of
spot may be present on the first abdominal segment (this spot is a practical method of recognizing Spodoptera larvae in the field), hypopharyngeal complexhypopharyngeal complex:
a structure consisting of the Hypopharynx, Labial palpi, and Spinneret
with coarsely spined posteriorposterior:
caudal or rear
portion lacking a dense brush of stout bristles, and cuticle smooth under low magnification. There appears to be variation in the spinneretspinneret:
a structure from which silk is spun, usually located on the labium of larvae
of S. littoralis based on the figures of Beck (1999-2000: figs. 903a on 345, 346). Spodoptera littoralis has SD1 hairlike on the mesothothorax, metathoraxmetathorax:
the third thoracic segment
and A9.

Passoa (2011)Passoa (2011):
Passoa, S. 2011. Field key to late instars of Spodoptera of America North of Mexico, pp. 386-387. In Wagner, D. L., D. F. Schweitzer, J. Bolling Sullivan and R. C. Reardon. Owlet caterpillars of eastern North America. Princeton University Press. compared S. littoralis to other North American Spodoptera as part of a screening key to allow more rapid recognition of these exotic species if ever introduced to North America. For typical specimens of S. littoralis, the ground color is a shade of chocolate brown to steel gray to dark olive green, only rarely is it light green. The subdorsal area is usually strongly contrasting with the paler dorsum, a middorsal line is usually faint or absent, the spiracular stripe not interrupted on A1 by a black band or spot and dorsaldorsal:
at the top or back or above
triangles, if present, are on all abdominal segments, A1 and A8, A7 and A8, or just A8. They nearly always lack an apicalapical:
at the end or the tip
white dot. Sometimes a white spot is present posteriorposterior:
caudal or rear
to the abdominal spiracles, more rarely there is also a dorsaldorsal:
at the top or back or above
black dot. Heavily marked later instars often have subdorsal white spots on the mesothoraxmesothorax:
the second thoracic segment
and metathoraxmetathorax:
the third thoracic segment
.

We have chosen the most common states in both morphology and color based on United States port interceptions. Exceptions to the above diagnosis are known and might be expected.

Identification Authority (Detailed)

Because the genus Spodoptera is hard to define as larvaelarva:
the stages between the egg and pupa of those insects having complete metamorphosis
, care must be taken to be sure the specimen is in this genus. The thoracic bar on SD1 occurs in many noctuids, it is not an indication of Spodoptera by itself. Morphological characters were described in detail above to help with doubtful cases. Both the morphology and color must match Spodoptera. If either is not correct, it is better to stay at family Noctuidae.

Accurate identification of S. littoralis involves origin, morphology, and color pattern. Spodoptera littoralis occurs in Europe, parts of Africa, and the Middle East (Pogue 2002Pogue 2002:
Pogue, M. G. 2002. A world revision of the genus Spodoptera Guenee (Lepidoptera: Noctuidae). Memoirs of the American Entomological Society 43. 202 pages.). Because this pest is polyphagous, the hostplant offers few clues. There are only three species of Spodoptera in Europe, and S. littoralis does not look like either S. exigua or S. cilium. Spodoptera exigua has a dark laterallateral:
to the side, or at the side of
mesothoracic spot that is absent in S. littoralis. The mandible of S. cilium normally lacks teeth (Brown and Dewhurst 1975Brown and Dewhurst 1975:
Brown, E. S. and C. F. Dewhurst. 1975. The genus Spodoptera (Lepidoptera, Noctuidae) in Africa and the Near East. Bulletin of Entomological Research 65: 221-262., Pogue 2002Pogue 2002:
Pogue, M. G. 2002. A world revision of the genus Spodoptera Guenee (Lepidoptera: Noctuidae). Memoirs of the American Entomological Society 43. 202 pages.) (but small teeth are shown by Beck (1999-2000) and again by Ahola and Silvonen [2008]) and the hosts are grasses. Teeth are present in S. littoralis and the host is usually not grasses. The presence of mandibular teeth separates S. littoralis from all African species except S. exigua according to Brown and Dewhurst (1975)Brown and Dewhurst (1975):
Brown, E. S. and C. F. Dewhurst. 1975. The genus Spodoptera (Lepidoptera, Noctuidae) in Africa and the Near East. Bulletin of Entomological Research 65: 221-262.. Thus, middle to late instar larvaelarva:
the stages between the egg and pupa of those insects having complete metamorphosis
of S. littoralis with a typical color pattern can be identified in Europe, Africa and the Middle East to Israel. Because S. littoralis occurs in Europe naturally, it is common on cut flowers from the Netherlands.

Early instars of S. littoralis have a slightly swollen thorax and usually either a band or a large black spot on A1. It might be possible to name young larvaelarva:
the stages between the egg and pupa of those insects having complete metamorphosis
from Europe if the mandible is dissected. Early instars from Africa and the Middle East should be left at genus. Preserved large larvaelarva:
the stages between the egg and pupa of those insects having complete metamorphosis
of S. littoralis often lose their color pattern leaving a row of contrasting and obvious black spiracles.

Unless the color pattern is unambiguous, specimens from Israel to Pakistan should be left at genus because of an overlap and possible confusion with S. litura.

Origin records

Spodoptera littoralis has been intercepted from the following locations:

France, Israel, Italy, Kenya, Netherlands, Palestinian Territory, Spain, Tanzania, Zimbabwe

Interception records from Thailand are likely misidentifications of S. litura.

Host records

Spodoptera littoralis has been intercepted on the following hosts:

Anemone sp., Anethum graveolens, Apium graveolens, Artemisia dracunculus, Asclepias sp., Asclepias tuberosa, Begonia sp., Bupleurum griffithii, Bupleurum sp., Capsicum annuum, Capsicum frutescens, Celosia sp., Coriandrum sativum, Delphinium sp., Eryngium sp., Eustoma grandiflorum, Eustoma sp., Gerbera sp., Lisianthus sp., Mentha longifolia, Mentha sp., Ocimum basilicum, Oncidium sp., Origanum majorana, Origanum vulgare, Ornithogalum sp., Phlox sp., Ranunculus sp., Rosa sp., Rosmarinus officinalis, Rumex sp., Thymus citriodorus, Thymus sp., Thymus vulgaris, Tulipa sp.