Larval and pupal stage of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) in sweet and field corn genotypes

Abstract

Spodoptera frugiperda, the fall armyworm, is a very significant polyphagous pest due to the damages it causes, and control difficulties. Lack of information about its impact on sweet corn motivated a comparison of its biology, with respect to the larval and pupal stages, among the genotypes ELISA, BR 400 (sweet corns), and BR PAMPA (field corn). In laboratory conditions (25 ± 1ºC; 70 ± 10% RH; photophase 12 hours), 35 caterpillars were individualized and fed daily with 3.14 cm 2 sections of corn leaves from the referred-to genotypes, cultivated in plots in the experimental area of the Departament of Fitossanidade, UFRGS, Porto Alegre, RS from October to November 2000. The caterpillars were weighed daily; after each molt, the cephalic capsules were collected and measured (in width), to establish growth rate; pupae were weighed and sexed when 24 hours old. The duration of the larval instars, the pupal sex ratio, and the mortality of larvae and pupae were evaluated. In the first three instars there were no differences registered in capsule width. In the fourth and fifth instars, capsules of caterpillars kept in BR 400 were smaller. The weight of caterpillars and pupae, instar duration and sex ratio did not differ among the genotypes. Pupal phase duration was less in females kept in BR 400. Mortality was greater in the larval phase in ELISA and in the pupal phase in BR PAMPA.Key words: Spodoptera frugiperda, fall armyworm, sweet corn. RESUMOFases larval e pupal de Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) em genótipos de milho doce e comum Spodoptera frugiperda, a lagarta-do-cartucho-do-milho, é uma praga polífaga de grande importância agrícola pelos danos e dificuldade de controle. A ausência de informações sobre seu impacto em milho doce motivou a comparação de sua biologia, no que tange as fases larval e pupal, entre os genótipos de milho ELISA, BR 400 (milhos doces) e BR PAMPA (milho comum). Em condições de laboratório (25 ± 1ºC; 70 ± 10% UR; fotofase 12 horas), 35 lagartas foram individualizadas e alimentadas, diariamente, com seções de folhas de 3,14 cm 2 dos referidos genótipos, provenientes de parcelas estabelecidas na área experimental do Departamento de Fitossanidade, UFRGS, Porto Alegre, RS, de outubro a novembro de 2000. As lagartas foram pesadas diariamente e após cada ecdise as cápsulas cefálicas eram recolhidas e mensuradas quanto à largura, para estabelecer a razão de crescimento. As pupas foram pesadas e sexadas com 24 horas de idade. Avaliaram-se a duração dos ínstares larvais, a razão sexual das pupas e a mortalidade larval e pupal. Não se registrou diferença na largura das cápsulas nos três primeiros ínstares. No quarto e quinto ínstares, as cápsulas das lagartas mantidas em BR 400 foram menores. O peso das lagartas e das pupas, a duração dos ínstares e a razão sexual não diferiram entre os genótipos. A duração da fase pupal foi menor nas fêmeas mantidas em BR 400. A mortalidade foi maior, na fase larval, em ELISA e, na pupal, em BR PAMPA.Palavras-chave: Spodoptera frug...

Developmental Parameters of Spodoptera frugiperda (Lepidoptera: Noctuidae) Immature Stages Under Controlled and Standardized Conditions

“…The high pupal survival reported here may be related to the availability of sterilized vermiculite, which avoids contamination, and facilitates the burrowing and chamber construction process, facilitating gaseous exchange and maintenance of humidity. Pupal duration was approximately nine days (Table 1), similar to other studies with favorable temperature conditions and suitable artificial diets or host plants (e.g., Campos F. 1970;Piedra, 1974;Kasten Jr. et al, 1978;Combs & Valerio, 1980;Pencoe & Martin, 1982;Pitre & Hogg, 1983;Parra & Carvalho, 1984;Crocomo & Parra, 1985;Pantoja, Smith, & Robinson, 1987;Castro & Pitre, 1988;Clavijo et al, 1991;Rizzo & La Rossa, 1992;Giolo et al, 2002;Murúa et al, 2003Murúa et al, , 2008Santos et al, 2003;Busato et al, 2005Busato et al, , 2008. Pupal weight was extremely variable (143 to 342 mg) (Table 4) but this variation was similar to that reported for specimens collected and reared in similar conditions in Brazil (140-340 mg) (Giolo et al, 2002) and in the United States (150-350 mg) (Leuck & Perkins 1972).…”

“…The growth ratio decreased progressively until the last instar (Table 3), a characteristic also reported in other studies of S. frugiperda (Nieto-Hernández & Llanderal-Cázares, 1982;Machado et al, 1985;Valverde et al, 1995;Santos et al, 2003;Capinera, 2008;Lopes et al, 2008;Maroneze & Gallegos, 2009) and other Spodoptera species, such as S. eridania (Parra, Precetti, & Karsten, 1977, Valverde & Sarmiento, 1987Montezano et al, 2014b), S. albula (Montezano et al, 2013a), S. dolichos (Montezano et al, 2015a) and S. cosmioides ).…”

“…For example, Lopes et al (2008) reported head capsule widths of 0.2 mm (first instar) to 1.4 mm (seventh instar) for S. frugiperda reared on cassava; a comparison to the range of 0.3 mm (first instar) to 2.7 mm (sixth instar) in the current study would suggest that cassava is a less suitable host. Alternatively, Santos et al (2003) reported only five instars (compared to six instars reported here for artificial diet) for S. frugiperda reared on certain cultivars of maize, indicating maize to be a highly suitable host plant. Other ecological stresses may be indicated if developmental parameters vary significantly from the established pattern; for example, parasitized S. frugiperda larvae may be smaller at the time of the final instar (e.g., Ashley, 1983;Ashley et al, 1989;Viana & Prates, 2003;Maroneze & Gallegos, 2009).…”

“…Studies addressing the differences between sexes during S. frugiperda larval development report those findings can depend on diet, temperature and biotype (host plant and locality), with reports of no differences (Combs & Valerio, 1980;Clavijo et al, 1991;Giolo et al, 2002) or females developing faster than males (Giolo et al, 2002;Nagoshi, 2011). For duration of pupal development, however, this study reported that development was longer for males than females (Table 2); this difference between sexes is well documented for S. frugiperda (e.g., Combs & Valerio, 1980;Pencoe & Martin, 1982;Parra & Carvalho, 1984;Crocomo & Parra, 1985;Lynch et al, 1989;Pantoja et al, 1987;Clavijo et al, 1991, Santos et al, 2003. The developmental delay of females during the larval stage was compensated by a faster pupal development, resulting in synchronization between male and female adult emergence, which was also reported for other species of Spodoptera reared under the same conditions (Montezano et al, 2013a(Montezano et al, , 2014b(Montezano et al, , 2015b.…”

LIFE CYCLE OF LABORATORY-REARED <i>ACROBASIS NUXVORELLA</i> NEUNZIG (LEPIDOPTERA: PYRALIDAE): A PECAN NUT PEST

“…The last segment of PNC pupae (Fig. 4) permits a relatively simple diagnosis (Marco et al, 1993;Santos et al, 2003;Perez-Guerrero et al, 2004). Table 2.…”