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PubMedDate not supplied

Insecticidal activity of synthetic amides on Spodoptera frugiperda.

The phytochemistry of the genus Piper (Piperaceae) has been widely studied due to the biological properties of amides from these plants. In this work, we have synthesized and evaluated the toxic effect of 11 amides against the fall armyworm Spodoptera frugiperda larvae. The naturally occurring piperine was also evaluated. The most active amide was N-[3-(3',4'-methylenedioxyphenyl)-2-(E)-propenoyl]piperidine with a LD50 of 1.07 microg mg(-1) larvae. This amide was also evaluated by ingestion.

Amides↗
PubMedDate not supplied

[Spatial distribution of plants infested with Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) on corn crop].

The importance of the fall armyworm, Spodoptera frugiperda (J.E. Smith), is not only due to the damage it can cause, but also to its difficult control. It is essential to know the pest population parameters, such as its standard scattering in the crop, because depending on the space arrangement of the insects in the area, different sampling methods are required. For the present work, three experimental fields were installed in different areas: the first one had 66 plots with seven plants each; the second one had 55 plots with four plants each; and the third field had 55 plots with six plants each. The presence or absence of the pest in the plant was evaluated in the samples. According to the data observed, either to the scattering index or to the theoretical scattering models, S. frugiperda dispersion is scattered at random and strongly depends on the infestation level.

Animals↗
PubMed2004

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

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 +/- 1 masculine C; 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.

Animals↗
PubMed2000

Changes in midgut endopeptidase activity of Spodoptera frugiperda (Lepidoptera: Noctuidae) are responsible for adaptation to soybean proteinase inhibitors.

The development of transgenic maize plants expressing soybean proteinase inhibitors could reduce the economic damage of one of the major maize pests in Brazil, the fall armyworm, Spodoptera frugiperda (J.E. Smith, 1797). We examined the influence of soybean proteinase inhibitors on digestive enzyme properties and development of S. frugiperda larvae. The inhibition of trypsin and chymotrypsin activities in vitro by soybean proteinase inhibitors suggested that either Kunitz (SBTI) or Bowman-Birk (SBBI) would have a potential antimetabolic effect when ingested by insect larvae. However, chronic ingestion of semipurified soybean inhibitors did not result in a significant reduction of growth and development of fall armyworm. Therefore, digestive serine proteinase activities (trypsin and chymotrypsin) of fall armyworm larvae were characterized. The results suggest that S. frugiperda was able to physiologically adapt to dietary proteinase inhibitors by altering the complement of proteolytic enzymes in the insect midguts.

Adaptation, Physiological↗
PubMed2001

Toxicity of pyrethroids and effect of synergists to larval and adult Helicoverpa zea, Spodoptera frugiperda, and Agrotis ipsilon (Lepidoptera: Noctuidae).

Based on 48 h LD50 estimates from topical bioassays, cypermethrin was more toxic than permethrin to Helicoverpa zea (Boddie) larvae and adults; however, the two pyrethroids did not differ significantly in their relative toxicities to Spodoptera frugiperda (J. E. Smith) and Agrotis ipsilon (Hufnagle). Larvae of each species generally were more susceptible to cypermethrin and permethrin than respective adults. The only exception to this generalization occurred with H. zea where slight overlap of the 95% confidence intervals with larvae and adult males was observed with cypermethrin. Respective males and females of the three species usually did not differ significantly in their susceptibility to either cypermethrin or to permethrin; however, with A. ipsilon, females were more susceptible to permethrin than to cypermethrin. Several instances of greater than additive toxicity were noted when insects were treated with piperonyl butoxide, S,S,S-tri-n-butyl phosphorotrithioate (DEF), or amitraz 30 min before cypermethrin. DEF exhibited the broadest spectrum of synergistic activity.

Animals↗
PubMed2001

Pharmacokinetic mechanisms associated with synergism by DEF of cypermethrin toxicity in larval and adult Helicoverpa zea, Spodoptera frugiperda, and Agrotis ipsilon (Lepidoptera: Noctuidae).

Penetration, metabolism, and excretion of radiocarbon were observed after topical treatment of Helicoverpa zea (Boddie), Spodoptera frugiperda (J. E. Smith), and Agrotis ipsilon (Hufnagle) larvae and adults with cypermethrin-14C. These pharmacokinetic events usually were higher with trans-cypermethrin-14C than with cis-cypermethrin-14C. They also were generally higher with H. zea and S. frugiperda than with A. ipsilon, and they were higher in larvae than in adults. No marked sex differences in the degradation of trans-cypermethrin were apparent. Pretreatment of H. zea, S. frugiperda, and A. ipsilon larvae and adults with S,S,S-tri-n-butyl phosphorotrithioate (DEF) 30 min before application of cypermethrin resulted in a perturbation of trans-cypermethrin pharmacokinetics manifested primarily by a lower rate of pyrethroid metabolism as compared with that in the absence of DEF. Appreciably higher internal levels of the toxic parent pyrethroid were often observed in the presence of DEF than in the absence of DEF in most cases. Suppression of cypermethrin penetration and elimination also was usually detected. Inhibition by DEF of the enzymatic degradation of cypermethrin may account for the synergy observed between these two compounds.

Animals↗
PubMed2001

DEF sensitive esterases in homogenates of larval and adult Helicoverpa zea, Spodoptera frugiperda, and Agrotis ipsilon (Lepidoptera: Noctuidae).

Homogenates of Helicoverpa zea (Boddie), Agrotis ipsilon (Hufnagle), and Spodoptera frugiperda (J. E. Smith) third instars and adults contained S,S,S-tri-n-butyl phosphorotrithioate (DEF)-sensitive enzymes that hydrolyzed trans-cypermethrin and two known esterase substrates, alpha-naphthyl acetate and beta-naphthyl acetate. Except for H. zea with alpha-naphthyl acetate, larval preparations were more active than those of adults, and no marked sex differences were apparent. The hydrolysis of trans-cypermethrin in noctuid preparations were inhibited by DEF, with pI50 values ranging from 4.5 to 6.7. DEF was a potent inhibitor of the degradation of general carboxylesterase substrates alpha-naphthyl acetate and beta-naphthyl acetate in some cases. Electrophoretic studies confirmed the presence in noctuid gut homogenates of one or more DEF-sensitive esterases that hydrolyzed alpha-naphthyl acetate and beta-naphthyl acetate and that were completely inhibited by dichtorvos.

Animals↗
PubMed2001

Sesquiterpene carboxylic acids from a wild tomato species affect larval feeding behavior and survival of Helicoverpa zea and Spodoptera exigua (Lepidoptera: Noctuidae).

The sesquiterpene carboxylic acids (SCA), (+)-(E)-alpha-santalen-12-oic, (-)-(E)-endo-alpha-bergamoten-12-oic, and (+)-(E)-endo-beta-bergamoten-12-oic acid, are produced in glandular trichomes of Lycopersicon hirsutum f. typicum Humb. & Bonpl. accession (LA) 1777, which is highly resistant to a range of pests of cultivated tomatoes. L. esculentum Mill. Exposure of the larvae of two key tomato pests, tomato fruitworm [Helicoverpa zea (Boddie)] and beet armyworm [Spodoptera exigua (Hübner)], to these compounds in diets and on leaf surfaces resulted in reduced development rates and survival and deterred feeding. These effects were observed when levels of SCA, in artificial insect diet, applied to leaflets of susceptible cultivars, or synthesized in trichomes of leaves of plants, exceeded 2 mg SCA/g of diet or fresh leaf weight. This study suggests that cultivated tomatoes capable of synthesizing SCA, at 2 mg SCA/g of leaf tissue or greater, on their leaves and fruit would display enhanced host plant resistance to H. zea and S. exigua and other insect pests.

Animals↗
PubMed2005

Spodoptera frugiperda pheromone lures to avoid nontarget captures of Leucania phragmatidicola.

We confirmed that commercial three- or four-component Spodoptera frugiperda (J.E. Smith) pheromone lures had a high nontarget capture rate for Leucania phragmatidicola Guenée, which compromised monitoring efforts in the northeastern United States. We compiled taxonomic features to distinguish L. phragmatidicola from S. frugiperda, and we compared five new lures. S. frugiperda catch specificity was improved by removing (Z)-11-hexadecen-1-ol acetate (Z11-16:Ac), which attracted L. phragmatidicola. Four lures tracked late-season S. frugiperda immigration, but two of these lures also tracked a bivoltine L. phragmatidicola flight with a second generation coincident with S. frugiperda immigration, and one lure attracted the first, but not the second, generation of L. phragmatidicola. In both low- and high-moth flight conditions, two-component lures had low L. phragmatidicola captures (0.5-1.4%), and although lures with more pheromonal components captured more S. frugiperda, they also had a high percentage of capture of L. phragmatidicola (38-48%). We conclude that although two-component lures captured fewer S. frugiperda, their similar temporal pattern, along with the lower level of L. phragmatidicola, makes them useful for development for monitoring programs in the northeastern United States.

Animals↗
PubMed2006

Oil-soluble dyes for marking Spodoptera frugiperda (Lepidoptera: Noctuidae).

Although various biological aspects of Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) have been examined, adult movement and dispersal of this insect pest is not well understood. Release-recapture techniques by using marked insects is a useful approach for dispersal studies; however, the marking technique should not significantly affect insect biology or behavior. Therefore, the effect of different concentrations of oil-soluble dyes (Solvent Blue 35 [C.I. 61554], Sudan Red 7B [C.I. 26050], Sudan Black B [26150], Sudan Orange G [C.I. 11920], and Sudan I 103624 [C.I. 12055]) on development, mortality, and fecundity of S. frugiperda was evaluated. Dyes were added to artificial diet used to feed larvae. Larval and pupal development and mortality, adult longevity, and female fecundity were evaluated. High concentrations (400 and 600 ppm) of all dyes led to longer larval and pupal stages. Adult life span and number of eggs were not affected by the dyes. Sudan Red 7B marked both adults and eggs very well. Solvent Blue 35 marked both adults and eggs, but the blue-marked eggs could not be distinguished from some bluish eggs laid by nonlabeled females. Adults and eggs were not adequately marked by the Sudan Black B, Sudan Orange G, and Sudan I 103624 (a yellow dye).

Animals↗
PubMed2006

Host plant resistance in romaine lettuce affects feeding behavior and biology of Trichoplusia ni and Spodoptera exigua (Lepidoptera: Noctuidae).

Lettuce quality and yield can be reduced by feeding of several lepidopterous pests, particularly cabbage looper, Trichoplusia ni (Hübner), and beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). Host plant resistance to these insects is an environmentally sound adjunct to conventional chemical control. In this study we compared the survival, development, and feeding behavior of cabbage looper and beet armyworm on two romaine lettuce cultivars, resistant 'Valmaine' and susceptible 'Tall Guzmaine'. Larval mortality of both species was significantly higher on resistant Valmaine than on susceptible Tall Guzmaine. The average weight per larva after feeding for 1 wk on Tall Guzmaine plants was 6 times (beet armyworm) and 2 times (cabbage looper) greater than that of larvae feeding on Valmaine plants. Significant reduction in larval growth on Valmaine compared with that on Tall Guzmaine resulted in a 5.9- (beet armyworm) and 2.6-d (cabbage looper) increase in larval duration and almost a 1-d increase in pupal duration. Average pupal and adult weights and successful pupation of cabbage looper and beet armyworm were reduced on Valmaine compared with Tall Guzmaine. The sex ratio of progeny did not deviate from 1:1 when larvae were reared on either Valmaine or Tall Guzmaine. The fecundity of cabbage looper and beet armyworm adults that developed from larvae reared on Valmaine was about one-third that of adults from Tall Guzmaine, but adult longevity did not significantly differ on the two lettuce cultivars. The two insect species showed different feeding preferences for leaves of different age groups on Valmaine and Tall Guzmaine. Cabbage loopers cut narrow trenches on the leaf before actual feeding to block the flow of latex to the intended site of feeding. In contrast, beet armyworms did not trench. The different feeding behavior of the two species on Valmaine may explain the superior performance of cabbage looper compared with beet armyworm.

Animals↗
PubMed2006

Expression of active alpha-N-acetylglucosaminidase/TAT Chimerae in cultured Spodoptera frugiperda cells.

We examined the production and secretion of fusion constructs containing alpha-N-acetylglucosaminidase, the enzyme deficient in Sanfilippo B, and either wildtype TAT or modified TAT in cultured Spodoptera frugiperda cells. All constructs exhibited successful expression of active enzyme, suggesting the future possibility of utilizing TAT/alpha-N-acetylglucosaminidase chimerae in enzyme replacement therapy.

Acetylglucosaminidase↗
PubMed2006

Vip3A is responsible for the potency of Bacillus thuringiensis 9816C culture supernatant against Helicoverpa armigera and Spodoptera exigua.

Culture supernatant of Bacillus thuringiensis 9816C had high toxicity against Helicoverpa armigera and Spodoptera exigua. However, it lost insecticidal activities after being bathed in boiling water for 5 min. Acrystalliferous mutants of Bt9816C (Bt9816C-NP1 and Bt9816C-NP2) cured of its endogenous plasmids no longer possessed vip3A gene and toxicity. The 89 kD protein which existed in Bt9816C supernatant disappeared in the two mutants' supernatant; nevertheless, the two mutants still exhibited hemolytic and phospholipase C activity as Bt9816C did. The vip3A gene of Bt9816C, vip3Aa18, was cloned and expressed in Escherichia coli BL21. Bioassay demonstrated that the recombinant E. coli had high toxicity against S. exigua. Taken together, it suggested that Vip3A protein was responsible for the toxicity of Bt9816C culture supernatants.

Animals↗
PubMed1999

Development of a novel expression vector system using Spodoptera exigua nucleopolyhedrovirus.

To develop a novel Spodoptera exigua nucleopolyhedrovirus (SeNPV) expression vector system, we examined characteristics of the SeNPV polyhedrin expression in S. exigua cells (Se301). While the extracellular virus titer of SeNPV was 100-fold lower than that of Autographa californica nucleopolyhedrovirus (AcNPV), the levels of polyhedral inclusion body (PIB) formation and polyhedrin expression were higher in SeNPV. To investigate foreign gene expression under the control of the polyhedrin promoter, polyhedrin-based transfer vector pSeKSK2 was constructed, and then recombinant virus SeK1-LacZ was constructed by inserting E. coli lacZ gene as a reporter gene into a genomic DNA of SeNPV using this transfer vector. The beta-Galactosidase activity of SeK1-LacZ in Se301 was about 1.3 times higher than that of BacPAK6. Thus, the SeNPV expression vector system constructed in this study would be very useful in the expression of foreign proteins, specifically for the enhancement of the pesticidal properties of SeNPV by inserting pesticidal genes.

Animals↗
PubMedDate not supplied

Comparison of the biological activities of human immunodeficiency virus 1 P24 and GP41 expressed in Spodoptera frugiperda cells by use of bac-to-bac system.

Recombinant transposing plasmids pFH24 and pFH41 were constructed by cloning the human immunodeficiency virus 1 (HIV-1) p24 and gp41 genes, respectively, into the transposing vector pFastBacHTa. Recombinant bacmids rBH24 and rBH41 were obtained by transposing pPolh/p24 and pPolh/gp41 expression cassettes from recombinant plasmids pFH24 and pFH41, respectively. Recombinant viruses rAcH24 and rAcH41 were generated by transfection of the Spodoptera frugiperda (Sf9) cells with the DNAs of plasmids rBH24 and rBH41, respectively. Analysis of the expressed p24 or gp41 proteins with an antiserum to HIV-1 (HIV-1 antiserum) by an enzyme-linked immunosorbent assay (ELISA) and dot blot assay showed high biological activity of these proteins; p24 was more active than gp41. Also a Western blot analysis showed stronger bands for p24 than for gp41. The high reactivities of p24 and gp41 with the HIV-1 antiserum suggest that these proteins could also be used as specific standard antigens in HIV-1 diagnostics.

Animals↗
PubMed2000

Growth inhibitory and antifeedant activity of extracts from Melia dubia to Spodoptera litura and Helicoverpa armigera larvae.

The growth inhibitory activity and deterrency of Melia dubia (Meliaceae) extracts to Spodoptera litura and Helicoverpa armigera were investigated. Artificial diet bioassays using neonate larvae of both S. litura and H. armigera indicated that dichloroethane (DCE) and methanol (Me) extracts of M. dubia inhibited growth in a dose dependent manner. DCE and Me-5II fractions also resulted in 50% deterrency at concentrations of 22.5 and 16.8 micrograms/cm2 respectively against S. litura larvae in a leaf disc-choice test. The DCE-5 fraction was found to be more toxic to larvae (LC50 of 0.65%) than the Me-5II (LC50 of 0.8%), 72 hr after topical application. Both fractions lack contact toxicity, but the deterrent effect persisted for at least 60 hr under laboratory conditions. Although salannin was isolated from the DCE fraction to show antifeedant activity, the physico-chemical characteristics of the active fractions DCE-5 and Me-5II were not identical with either salannin or azadirachtin.

Acetates↗
PubMed2000

[Effect of temperature and food on Spodoptera litura population].

The relationship between temperature and development of Spodoptera litura was simulated by the sine model V(T) = A + B sin(C0 + C1eC3T + C2e-C3T), and the threshold temperature and thermal requirement for its development at different stages were estimated by the direct optimum method. The model for the relationship between temperature and survival rate was fitted by the experimental data. The theoretical optimum temperature for the development of eggs, young instar larvae, old instar larvae and pupae was 26.7, 24.7, 24.9 and 25.8 degrees C, respectively. The life table parameters under different feed conditions (cabbage, lotus, sweet potato, soybean leaves) were estimated by the method of bisexual life table with age-structure. At temperature 25 degrees C, the intrinsic rates of increase under the four different feed conidtions were 0.1836, 0.1719, 0.1778 and 0.1206, respectively.

Animals↗
PubMed2000

[Epizootic dynamics of Spodoptera litura nuclear polyhedrosi virus].

Through investigation of tracking infected Spodoptera litura larvae, the epizootic dynamics of S. litura nuclear polyhedrosis virus(SlNPV) in field was studied with different dosages of SlNPV. The results showed that in the range of virus dosages (3.1 x 10(5)-3.1 x 10(8) PIBs.ml-1), the initial infection syndrome was observed after 4 days of treatment, and peaked in 5-7 days. The larvae mortality occurred after 5-6 days of treatment, and peaked in 6-8 days. The prevalence peak of host was basically coincident to the incidence peak. The distribution of diseased incidence of hosts and disease death time could be quite simulated by time-dosage-mortality model(TDM). Hosmer-Lemoshow test showed that the predicted values well fitted with observed data, and t-test indicated the parameters of the model reached significant level(P < 0.0001). The distribution of diseased prevalence was simulated by Holliday model, the regression of function was significant by F-test, and the parameters of the model reached or approached significant level(p < 0.005). TDM model could be used to predict the daily incidence, prevalence, disease death rate of present generation population of host pest.

Animals↗