Vol. 5, No. 3-4, September-December 1991 185

Color identification of economically important larvae in Honduras (: )

S Passoa USDftJAPHISlPPQ 8995 E. Main Street Bldg. 3, Room 109 Reynoldsburg, OH 43068

Abstract Spodopterafrugiperda (J. E. Smith), S. exigua (HUbner), S.lati(ascia (Walker), S. ornithogalli (Guenee), S. dolichos (Fabricius), S. sunia (Guenee), and S. eridania (Cramer) are commonly associated with crops in Honduras. A key to these species with color illustrations ofrare and typical forms is presented. Potential problems in identifying Spodoptera species are discussed.

Additional key words: morphology.

Introduction mens are misidentified (Figures 9.1, 9.4, and 11.2 label three forms of S odo tera lati ascia as S. pests throughout the world (Kranz etal. 1977, Hill ] 975) At least eight species are known to occur in 1 Honduras. Spodoptera frugiperda (J. E. Smith), azzom e al. mcorrect y la e ed a p oto- Spoooptera exigua (Hubner), Spodoptera lati{Q.scia graph ofS. 8unia as S. eridania. PNalker), and 8podoptera sunia (Guenee) are eon This work should facilitate identification of sidered economically important pests whereas common Spodoptel a 1m vae in Honduras by pI esen- Spodoptera eridania Wratner), Spodoptera orni- ~~;e~~;~:~~~~~o:o~~~~:~:~:~o~;:i~:~~ thogalli (Guenee), and Spodoptera dolichos (Fabri­ cius) are rarely abundant enough to cause serious allow accfrate identification of most Spodoptera damage to Honduran crops (Passoa 1983). An adult Spodoptera androgea (Cramer) was collected onthe north coast of HondUIas (La Lima, DepaItment of impossible. Cortes) in October, but its larva is unknown. The host range of Spodoptera is very wide including Methods and Materials most vegetable crops and several basic grains (passoa Most ofthe specimens used in this study were 1983, Andrews 1984, King and Saunders 1984). eoIIeeted in Honduras, Central Ameriea, from 1979 Information on the distribution, phenology, Span- 1981. Additional specimens from Ohio, Illinois and ish common names, biology, and control ofSpodoptera were also studied. Field-collected larvae spp. can be found in the works cited above. were photographed, reared to adult, and then iden- In spite ofa logical and thorough study by Levy tified with Todd and Poole (1980). Eggs laid by and Habeck (19'76), workers in Latin America female in captiVity proVided another source sometimes have trouble identifying Spodoptera of larval material. Beans (Phaseolus vulgaris L.), lanae. Two examples illustrate this problem. In sweet potato (Ipomoea halalas (L.) Poir.) or wheat King and Saunders (1984), several Spodoptera speci- germ artificial dietwere all accepted by Spodoptera 186 Insecta Mundi larvae in laboratory feeding trials Larval speci- 1. Dorsal pInacula usuallyconspicuous (Figs. 12, 14) mens were killed in a 9:1 mixture of 80% ethanol but sometimes pale in the green form (Fig. 13), and glacial acetic acid by volume, then tranSfurred their diameter equal to or greater than the dia- to 80% ethanol after 24 hours for permanent stor- meter ofthe abdominal spiracles dorsum ofab­ age. Larval terminology follows Stehr (1987). The dominal segments granulated under a mag- nification of25 power or greater (Fig. 4) . ~~oe;:~k:d~rl~:al::~~~;::~:::;:,:~;;~ ...... Spoduptera fru8iperda (J. E. Smith) I'. Dorsal ~inaculanever cons~icuous.theirdiameter the most common synonyms are mentioned under each species, for a more complete list see Todd and Poole (1980).

2. Abdominal segments neyer with dorsal triangular markingl3 pattern consists of a series ofdorsal dashes (Fig; 6) or, more commonly, an inegular

spot, if present, is on the mesothorax (Fig. 1) ventral tonofibrillary platelets between abdominal prolegs form a "Y" with a short stem about as long as the anns (Fig. 9) ...... Spodoptera exigua (Hubner) 2'. Abdominal segments with at least one pair of dorsal triangular markings (Figs. 2, 11, 23) 1. Four abdominal prolegs present (larva not a lateral spot, ifpresent, is on the first abdominal segment (Figs. 2, 19) ventral tonofibrillary plate­ ~o~) lets between abdOminal prolegs form a straight 2. 0 setae present on first abdominal seg- line or, morerarely, a"Y" with a'very long stem ment (Fig. 2). compared to the arms (Fig. 10) 3 3. Lateral spotusually present on first abdominal segment(this spotis a practicalmethodofrec- 3. Lateralspotonthefirst abdominal segment, when ognizing Spodoptera larvae in the field) (Fig present, interrupts the subspiraGular line to 2, 26). torm a pale, thInner lIne on the thorax (Fig. 19) 4. Mesothorax with a sclerotized bar connecting if lateral spot and/or subspiracular line are theSD1 setaanda tonofibrillaryplatelet(Fig. absent (F'lgS. 18, 20), then dorsal triangles ot 3). first abdominal segment larger than dorsal tri- No retin 1 m n h m n i angles ot tourth abdomInal segment (F'lg. 17) 3'. Lateralspotonthefirst abdominalsegment, when present, does not inb>mlpt the sUhspiracular line and therefore the line maintains equal in­ tensity and Width on thethorax compared tothe notch (Fig. 8). abdomen if lateral spot and/or subspiracular 8. Skin smooth under a magnification of25 power line are absent, then dorsal triangles of first (except in Spodoptera frugiperda) and never abdominal segment not larger than dorsal tri- WIth mrcrospmes. 9. Head with an inverted "Y" because adfrontal areas are outlined in white (see discussion under Spodoptel a Ii ugipelda) (Fig. 32). 4 them (Fig. 27), if lines are inconspicuous or absent in darkforms (Figs. 24-25, 28), then area Key to common Spodoptera larvae belowsubdorsal stripewith several longitudinal in Honduras narrowwhitelines(Fig. 24) dorsalmesothoracic (modifiedfrom !HI)'andHabook 1976, Oliverand Chapin markingeither tIiangular, elongate-oval, or semi- 1981, Crumb 1956, and Godfrey 1987) circular (Figs. 11, 32) ...... Spodoptera ornithogalti (Quenee) 4.' Dorsal triangles never with a narrow white line passingthroughthem, although a seriesofwhite Vol. 5, No. 3-4, September-December 1991 187

dots may be present (FigS. 31, 34) area below with cutwormsthathave granulated skin and large subdorsal stripe without several longitudinal pinacula, for example, Agrotis ipsilon (Hufnagel). narrow white lines except for the black form of However, cutworms have the adfi'OntaI suture ex S.latifascia (Fig. 34) dorsalmesothoracicmark­ tendingtothe epicranialnotch(top ofhead) whilein ings semicircular or trapezoidal (Figs. 32, 33), S. frugiperda the adfrontal area extends only half never triangular or elongate-oval 5 that distance. 5. $podOptera ( Laphygma) exigua (HQbner); beet armyworm A heavily-marked form of the beet armyworm wasillustratedbyLevy and Habeck (1976), butthis 5'. color pattern is rare in Honduras. Instead, most of low the tI i,iIlgles OIl th., subdral Ii e(Fig. the larvae are speckled with white on a green 30) 6

6. Mesothmacic dOl sal mmkings usually semicir- present (Fig. 16). SpoMptera exigua canusually be cular (Figs. 32, 34) and smaller than dorsal tri­ recognized by a lateral spot on the mesothorax (see angles on eighth abdominal segment (Fig. 11) discussion under 8. (rugiperda). However, presened rarely mesothoracic dorsal markings are re- specimens ofS. exigua usually fade in alcohol and placed by a ','mite spot (Fig. 31) .. lose theircolor pattern so mostidentificationsmust ...... Spodoptera latifascia (Walker) be confirmed with stmctnral characters Among 6'. Mesothoracie dorsal markings trapezoidal (Fig. common noctwds In agrIcUltural fields In Hon­ 30) and subequal to dorsal triangles on eighth duras, the presellGe ofh'lo subventral setae on the abdominal segment (Fig. 29), these markings never replaced by a white spot .. first abdominal segment (Fig. 2), a sclerotized bar ...... Sp9doptera doliGR,()s (FabriGius) connecting the mesothoIacic SD 1 seta to a tOllofib- rillary platelet (Fig. 3), the ventral tonofibrillary Discussion platelets intheform ofa ''Y'' with a short stem (Fig. 9), and smooth skin under a magnification of 25 power will Identify S. eXlgua. Spodoptera ( Lapbygma) frugiperda (J. E. Smith); fall armyworm. Spodoptera (-Xylomyges) eridania (Cramer); Usually Spuduptera frugipetda is readily distill- southern armY'tVorm Despiteitsname, the southernarmywonn isnot as common in Honduras as S. frugiperda, S. sunia, orS.latifii,sCia. Sj)odoptgra g1idania has beentradi 15 and 16) because the pale pinacula ofS. frugiper­ tionally distinguished by the spot on the first ab­ da are easy to ovetlook, especially in field surveys. dominal segment which interrupts the subspiracu- Cuticular texture can also be used to distinguish larline Lev andHabeck 1976 .However theterm i i ce e

Instead, the subspiracular line loses intensity as it passesbelowthelateral spot(Fig. 19). Most8pooop tera larvaehave a lateral spotso thecondition ofthe subspiIacwaI linemustbenoted. TheillustIatiollof

wasprobablymisidentifiedasS. eridania becauseof its prominent lateral spot Unfortunately, sometimes the subspiracular line of 8. eridania is pale (Fig. 9) or absent (Fig. 8). Under these circumstances the southern a~~ wonn is difficult to recognize. One character whl appears l1Di

identjfication of Honduran Spodoptera larvae, al- Angulo, A. 0.,and GT WeigeH. 1975a Estados though these characters might be significant if inmaduros de lepid6pteros n6ctuidos de impor- additional species are considered. Thepresenceand tancia econ6mica en Chile y da....es para su color ofthe middorsal line varies and itis especially determinacion (Lepidoptera: Noctuidae). Socie- obvious and intense in some S. sunia and S. el i­ dad de Biologia de Concepcion (Chile) Publi­ dania. Ideally,Spodoptera larvae needto be studied cacion Especial 2. 153 pp by reanngfemales in laboratory cultures for many generations, at several densities andtemperatures, Angulo, AO O. 1975b NoctUidae (Lepidoptera) de on a wide varietyofhostplants. Onlyinthiswaycan interes economica del valle de Ica, Peru: Clave we beginto understand the extentoreolor variation para estados inmaduros. Rev. Peruana Entomol. in these . 18 (1): 98-103.

Commonwealth Institute ofEntomology. 1977 ACknowled~ements DlstnbutIon maps of pests. SpOdoptera or- I am grate to all Peace Corps volunteers and nitkogalli (an.) Series A (Agriculture), map no. agronomists ofthe Department ofNatural Resour 367. London, England. 2 pp. ces who helped me collect specimens in Honduras. Dr. D. Habeck (University of Florida) deseIVes cru: S. E. 1929. Tobacco cutworms. U.S. Dep. special thanksfor all histimeand effortinreview of ·c. Tech. Bull. 88. 179 pp. , this manuscript. The comments ofDrs K. Andrews, R Cave and Crumb,S.E.1956. LarvaeofthePhalaenidae.U.S. R. Caballero (Panamencan AgricUlture School, Dep. Agrie. Teeh. Bull. 1136. 366 pp. Honduras), Dr. G. Godfrey (Illinois NaturalHistory Survey)...and Dr. M. Berenbaum (University ofIlli- (University of Delaware) kindly provided a photo- graph ofS. ornithogalli (Fig. 26). Godfrey, G.1987. FamilyNoetuidae. p.649 579. In Bibliography F. Stehr(Ed.), ImmatureInsects. KendalllHunt Publishing Co. Dubuque, Iowa. 754 pp. The following is a selectedbibliography ofrefer- ences useful in studyingSpoduptela spp. because of mil, D.S. 19'15. AgrIcUltural msect pests of, the tbeir illustrations or biological notes tropics andtheireontrol. CambridgeUniversity Press. Cambridge, England. 516 pp. Andrews, K. 1980. The \..'borlworm, SpOiJOptera {rugiperda, in Central America and neighboring Howell, Jr., HoN. 1978 Fall armyworm in a pine aleas. Fla. Entomol. 63 (4). 456-467. nursery in Honduras, C.A Celba 22 (1): 35-37.

Andrews, K. 1984. EI manejo integrado de plagas King, AD.S., and J.L. Saunders. 1984. The in­ jnvertebradas en cn1tivos agronomjcos, bOfficoJas vertebrate pests ofannualrood crops in Central yfrutalesenlaEscuelaAgricolaPanamericana. America Overseas Development Administration. Guia para ellaboratorio de eampo en entomol London, England. 166 pp. ogia. EI Zamorano, Honduras. 86 p. Kranz, d., H. Schmutterer, and W. Koch. 1977. Angulo, A. 0., and C••lana S 1982 La pnpa de Diseases, pests and ;veeds in tropieal erops. Spodoptera Guenee, 1852, en el norte de Chile Verlag Paul Parey. Berlin, Germany. 666 pp. (Lepidoptera: Noctuidae). Agric. Tacnica (Sa ntiago) 42 (4): 347-349. Levy, R., and D.H.Habeck. 1976 Descriptions of the larvae ofSpoooptera sumaand S.latLfascLa with a key to the mature SpocWptera larvae of the Eastern United States. Ann. EntomoL Soc. Am. 69 (4): 686 688. 190 Insecta Mundi

Luginbill, P. 1928 The faJ] annywonn II S Dep Passoa, S. 1983 Lista de los insectos asociados Agric. Tech. Bull. 34. 91 pp. con los granos basicos y otros cultivos selectos en Honduras. Ceiba 25 (1): 1 98. Marti, O.G., and C.E. Rogers. 1988. Anatomy of the "entral eversible gland of fall army worm, Peairs, FoB., and JoL. Saunders. 1979. The fan Spodoptera frugiperda (Lepidoptera: Noctuidae), armyworm, Spodoptera {rugiperda, a review. larvae. Ann. Entornol. Soc. Am. 81 (2). 308-317. Cerna 23 (2). 93-113.

NgoDong,T.C.Carlysle,H.L.Cromroy,andD. Peterson, A. 1962. Larvae of Insects. Edwards B:Habeck. 1980. Morphological studies onthe Brothers Inc.•4..nn Arbor, Michigan. 732 pp. beet armyworm, Spodoptera exigua (Hubner) (Lepidoptela. Noctuidae) Florida Exp. Sta Dull. Redfern, RoE. 1967. InstalS of southem mmy­ 816.38 pp. worm determined by measurement of head capsule. J. Econ. Entomol. 60 (2): 614-615. OkUmura, G.T. 1961 IdentifiCation of lepidop- terous larvae attacking cotton. California Dep. Rings, R.W., and G.J. Musick. 1976. A pictorial Agric. Special Pub. 282. 80 p. field key to the armyworms and cutworms at­ tacking corn in the North Central States. Ohio Oliver,AoD., andJoB. Chapin. 1981. Biology and Res. and Dev. Center Cire. 221. 36 pp. illustrated key for the identification of twenty species ofeconomically important noctuid pests. Todd, E.L., and R.W. Poole. 1980. Keys and Sta Agric. Exp 8ta. Bull. 733. 26 pp. illustratiOns fOr the armyworm moths of the noctuid genus Spodoptera Guenee from the Pashley,D.P. , SoJ. Johnson, and AN. Sparks. lNestern Hemisphere. Ann. Entomol. Soc.•Am. 1985. Geneticpopulationstructureofmigratory 73 (6): 722-738. moths. the fall armywonn (Lepidoptera. Noe- tuidae) Ann Entomol Soc Am 78 (6)' 756-762 Walkden, H.H.1950 Cutworms, annyworms and related species attacking cereal and forage crops Pashley, DOP., S.J. Johnson, and ...... N. Sparks. in the Central Great Plains. U.S. Dep. Agrie. 1986. Host-associatedgenetic differentiationin Circ. 849. 52 pp. fall mmYWOlm (Lepidoptela. Noctuidae). a sib­ ling species complex? Ann. Entomo!. Soc Am Whelan, DoB. 1935 A key to the Nebraska cut- 79 (6): 898-904. worms and armyworms that aUack corn. Ne- biaska AgriC Exp. 8ta. BUll 81.25 pp. Pashley, D.P., S.J. John~n,and A.N. Sparks. 1988. Quantitative genetics, development, and physiological adaptation in host strains offall armyworm. Evolution 42 (1). 93-102.

Figure 1-11. 1) Lateral view of typical Spodoptera head, prothorax and mesothorax. 2) Lateral view of a typical Spodoptera first abdominal segment. 3) SD 1 pinaeulum of a typieal Spodoptera larva. Arrow points to a tonofibrillary platelet which is connected to the pinaculum by two scI erotized bars. 4) Granulated cuticular texture Of SpgdOptera frugiperaa dorsum at high p0'ller. 5) Mandible of a typieal SpoMptera larva showing the lack ofa retinaculum. 6) Dorsal view ofSpodoptera exigua abdominal markings thatarenottriangular. 7) Lateral view Of typical Spgdoptera larval hypopharyngeal eomplex:. P-..rrow points to a hypopharyngeal blade whieh is sometimes present. 8) Anterior view oftypical Spodoptera head showing that adfrontal area (bottom arrow) does not reach the epicramal notch (top arrow). 9) Tonofibnllary platelets between the prolegs ofA3-6 In SpOdoptera exigua Arrow points to a "Y" with a short stem 10) Tonofibrillary platelets between the prolegs ofA3-6 in most SpOdoptera larvae that torm a straIght hne or a "y' WIth a long stem (see arrow). 11) Dorsal VIew ot SpodOptera lo.tifnscia showing that the mesothoracic markings (top arow) are smaller than the dorsal abdominal triangles of AS (bOttom arrow). A - antenna; Ad - adlrontlil area; D - dorslil area; F - front; G - prothoraclc ventral gland; H ­ hypopharyngeal complex and spinneret; L = lateral area; L3 = third lateral seta; Mn = mandible; P = maxill!llY palpus; 8 = lateral spot of fuet abdominal segment, 8 laleta! spot of tire mesothOlax, SA subdo1sal alea, SB - subsphaculal line, SDI fust subdorsal seta; 8L = subdorsal line; 8V = subventral area; 8V3 = third subventral seta; 8VI = fIrst subventral seta; T = dorsal abdonnnal tnangle; V - ventral area. Vol. 5, No. 3-4, September-December 1991 191

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Figure 12-17. Spo

Fipre 18-26. SpoOOptera spp. larvae. Figure 18-20. SpoOOptera eridania. 18) Dark form, showing the lack ofa subspiracular stripe; 19) Normal form, showing the reduction ofintensityandwidthofthe Bubspiracularline U itpUBeS underthelateral spot ofthe first abdominal segment. Arrows point to subspiracularline before and after it pa8BeS underthe lateral spot; 20) Dark form, showing a pale subspiracular stripe. Figure 21-23. Spodoptera Bunia. 21) Variegated color form; 22) Dorsal triangle (markedby arrows), showing a wbitespot near the apex; 23)Dorsal view, showing reduction ofthe dorsal triangles on most abdominal segments. Arrow pointsto a white spotringed withblackonthe posterior margin. Figure 24-28. SpoOOp­ tera omithcgolli. 24)Blackform, showingseveralwhitelinesbelow thesubdorsalstripe; 25)Darkform, showinginconspicu­ ous lines passing through the dorsal triangles; 26) Brown form, arrow points to lateral spot. Vol. 5. No. 3-4. September-December 1991 195

Figure 27·34. Spodoptera spp.larvae. Figure27-28. Spodoptera omithogolli. 27) Normalfonn, showinglines passing through the dorsal triangles (see arrow) and a yellowish-white subdorsal stripe; 28) Dark form, showing inconspicuous lines passing through the dorsal triangles. Figure 29-30. Spodoptera dolichos. 29) Dorsal view, showingmesothoracic dorsal marking(top arrow) as largeas the dorsal triangles ofthe eighth abdominalsegment (bottom arrow); 30) Dorsal view, showing trapezoidal mesothoracic dorsal markings. Figure 31-34. Spodoptera latifascia. 31) Black form, arrow points to a series ofwhite dots on the dorsum; 32) Dorsal view, arrow points to the semicircular mesothoracic dorsal marking; 33) Brown fonn, showing the lack ofdorsal abdominal triangles; 34) Black fonn, showing the orange subdorsal stripe and round mesothoracic dorsal markings. 196 Insecta Mundi