University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Center for Systematic Entomology, Gainesville, Insecta Mundi Florida September 1991 Color identification of economically important Spodoptera larvae in Honduras (Lepidoptera: Noctuidae) S. Passoa USDA/APHIS/PPQ Follow this and additional works at: https://digitalcommons.unl.edu/insectamundi Part of the Entomology Commons Passoa, S., "Color identification of economically important Spodoptera larvae in Honduras (Lepidoptera: Noctuidae)" (1991). Insecta Mundi. 414. https://digitalcommons.unl.edu/insectamundi/414 This Article is brought to you for free and open access by the Center for Systematic Entomology, Gainesville, Florida at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Insecta Mundi by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Vol. 5, No. 3-4, September-December 1991 185 Color identification of economically important Spodoptera larvae in Honduras (Lepidoptera: Noctuidae) S. Passoa USDAIAPHISIPPQ 8995 E. Main Street Bldg. 3, Room 109 Reynoldsburg, OH 43068 Abstract Spodoptera frzgiperda (J.E. Smith), S. exigua (Hiibner),S. latifascia (Walker),S. ornithogalli (Guenb), 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 of rare and typical forms is presented. Potential problems in identifying Spodoptera species are discussed. Additional key words: morphology, Noctuoidea Introduction mens are misidentified (Figures 9.1, 9.4, and 11.2 The noctuid genus Spodoptera contains many label three forms of Spodoptera latifascia as S. pests throughout the world (Kranz et al. 1977, Hill dolichos, S. eridania, and Spodoptera ornithogalli, 1975). At least eight species are known to occur in respectively). A guide to soybean pests in Brazil Honduras. Spodoptera frugiperda (J. E. Smith), (Gazzoni et al. 1981) incorrectly labeled a photo- Spodoptera exigua (Hiibner),Spodoptera latifascia graph of S. sunia as S. eridania. (Walker), and Spodoptera sunia (Guenee) are con- This work should facilitate identification of sidered economically important pests whereas common Spodoptera larvae in Honduras by presen- Spodoptera eridania (Cramer), Spodoptera orni- tingillustrations of typical andunusual color forms. thogalli (Guenbe), and Spodoptera dolichos (Fabri- Careful attention to details of the color pattern will cius) are rarely abundant enough to cause serious allow accurate identification of most Spodoptera damage to Honduran crops (Passoa 1983). An adult species, although greatvariation in larval markings Spodoptera androgea (Cramer) was collected on the makes the identification of all aberrant individuals north coast of Honduras (La Lima, Department 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 of the specimens used in this study were 1983, Andrews 1984, King and Saunders 1984). collected in Honduras, Central America, from 1979- Information on the distribution, phenology, Span- 1981. Additional specimens from Ohio, Illinois and ish common names, biology, and control of Spodoptem Florida 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 of a logical and thorough study by Levy tified with Todd and Poole (1980). Eggs laid by and Habeck (1976), workers in Latin America female moths in captivity provided another source sometimes have trouble identifying Spodoptera of larval material. Beans (Phaseolus vulgaris L.), larvae. Two examples illustrate this problem. In sweet potato (Ipomoea batatas (L.) Poir.) or wheat King and Saunders (19841, several SpaEoptera speci- germ artificial diet were all accepted by Spodoptera Insecta Mundi larvae in laboratory feeding trials. Larval speci- Dorsal pinacula usually conspicuous (Figs. 12,14) mens were killed in a 9:l mixture of 80% ethanol but sometimes pale in the green form (Fig. 13), and glacial acetic acid by volume, then transferred their diameter equal to or greater than the dia- to 80% ethanol after 24 hours for permanent stor- meter of the abdominal spiracles dorsum of ab- age. Larval terminology follows Stehr (1987). The dominal segments granulated under a mag- nification of 25 power or greater (Fig. 4) hypopharyngeal complex was mounted in glycerin ........ .............. Spodoptera frugiperda (J. E. Smith) and examined under a compound microscope. Only Dorsal pinacula never conspicuous, their diameter the most common synonyms are mentioned under less than the diameter of the abdominal spir- each species, for a more complete list see Todd and acles dorsum of abdominal segments smooth Poole (1980). under magnification of 25 power .................. 2 Characters to separate Spodoptera from other Abdominal segments never with dorsal triangular common pest noctuids in Honduras markings, pattern consists of a series of dorsal dashes (Fig. 6) or, more commonly, an irregular The following combination of structural and series of white dots and lines (Fig. 15) lateral color characteristics will separate Spodoptera spp. spot, if present, is on the mesothorax (Fig. 1) from other common pest noctuids in Honduras. The ventral tonofibrilllary platelets between abdominal polarity of most of these characters are unknown prolegs form a "Y' with a short stem about as although the presence of a sclerotized bar around long as the arms (Fig. 9) .................................. the mesothoracic SD 1seta seems to define a clade .......................... Spodoptera exigua (Hiibner) which includes Spodoptera and related genera. 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, if present, is on the first abdominal segment (Figs. 2,19) ventral tonofibrillary plat. looper). lets between abdominal prolegs form a straight 2. Two setae present on first abdominal seg- SV line or, more rarely, a "Y" with gvery long stem ment (Fig. 2). compared to the arms (Fig. 10)...................... 3 3. Lateral spot usually present on first abdominal segment (this spot is a practical method of rec- Lateral spot on the first abdominal segment, when ognizing Spodoptera larvae in the field) (Fig. present, interrupts the subspiracular line to 2,26). form a pale, thinner line on the thorax (Fig. 19) 4. Mesothorax with a sclerotized bar connecting if lateral spot and/or subspiracular line are the SD 1setaand a tonofibrillaryplatelet (~ig. absent (Figs. 18, 20), then dorsal triangles of 3). first abdominal segment larger than dorsal tri- 5. No retinaculum on the mandible (Fig. 5). angles of fourth abdominal segment (Fig. 17) Spodoptera eridunia (Cramer) 6. Hypopharyngeal complex with coarsely spined ........................ Lateral spot on the first abdominal segment, when posterior portion lacking a dense brush of present, does not interrupt the subspiracular stout bristles (Fig. 7). line and therefore the line maintains equal in- 7. Adfrontal sutures do not extend to epicranial tensity and width on the thorax compared to the notch (Fig. 8). abdomen if lateral spot and/or subspiracular 8. Skin smooth under a magnification of 25 power line are absent, then dorsal triangles of first (except in Spodoptera frugiperda) and never abdominal segment not larger than dorsal tri- with microspines. angles of fourth abdominal segment (Fig. ll) 9. Head with an inverted "Y'' because adfrontal areas are outlined in white (see discussion under Spodoptera frugiperda) (Fig. 32). Dorsal triangles with a narrow white line (either solid or composed of dashes) passing through them (Fig. 27), if lines are inconspicuous or absent in dark forms (Figs. 24-25,28), then area Key to common Spodoptera larvae below subdorsal stripe with several longitudinal in Honduras narrow white lines (Fig. 24) dorsal mesothoracic (modifiedfromLevy and Habeck 1976, Oliver and Chapin marking either triangular, elongate-oval,or semi- 1981, Crumb 1956, and Godfrey 1987) circular (Figs. 11, 32) ...................................... .................. Spodoptera ornithogalli (GuenBe) Dorsal triangles never with a narrow white line passing through them, although a series of white Vol. 5, No. 3-4, September-December 1991 dots may be present (Figs. 31, 34) area below with cutworms that have 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 adfrontal suture ex- S. latifascia (Fig. 34) dorsal mesothoracic mark- tending to the epicranial notch (top ofhead) while in ings semicircular or trapezoidal (Figs. 32, 33), S. frugiperda the adfrontal area extends only half never triangular or elongate-oval .................. 5 that distance. 5. Dorsal triangles with a white spot close to or at their apex (Fig. 22) if triangles are absent then Spodoptera (= Laphygma) exigua (Hu bne r) ; at least some of the white dots are bordered by beet armyworm black semicircles (Fig. 23) ................................ A heavily-marked form of the beet armyworm .............................. Spodoptera sunia (GuenBe) was illustrated by Levy and Habeck (19761, but this 5'. Dorsal triangles without a white spot close to their color pattern is rare in Honduras. Instead,