ABSTRACT
ABSTRACT:The present research updates the systematic position and nomenclature of Lepidoptera associated with soybean crops in Argentina, Brazil, Chile and Uruguay. Scientific literature lists 69 species of Lepidoptera feeding on soybean plants. These species are representatives of the Superfamilies Noctuoidea(31),Pyraloidea(13), Hesperioidea(12), Tortricoidea(5), Geometroidea(5), and Bombycoidea(3). Diversity of Lepidoptera associated to crop, injury in different parts of the plant, and changes in species composition are discussed considering the changes in plant disease management, introduction of plants expressing Bt proteins, and the recent introduction of Helicoverpa armigera(Hübner) as a new crop pest.
RESUMO:O presente estudo atualiza a posição sistemática e a nomenclatura dos lepidópteros associados com a cultura da soja na Argentina, Brasil, Chile e Uruguai. A literatura científica relaciona 69 espécies de Lepidoptera cujas larvas se alimentam de soja. As espécies incluem representantes das Superfamílias Noctuoidea(31),Pyraloidea(13), Hesperioidea(12), Tortricoidea(5), Geometroidea(5), and Bombycoidea(3). A diversidade dos lepidópteros associados com a cultura, as injúrias em diferentes partes da planta e alterações na composição das espécies são discutidas considerando mudanças no manejo de doenças da cultura, a introdução de plantas expressando proteínas Bt e a recente introdução de Helicoverpa armigera(Hübner) como uma nova praga da soja.
ABSTRACT
This study aimed to detail the temporal and morphological parameters of the immature stages of southern armyworm Spodoptera eridania (Stoll, 1782) with larvae feed on artificial diet, under controlled conditions (25 ± 1°C, 70 ± 10% relative humidity and 14-h photophase) and gather information about their larval host plants. The viability of the egg, larval, pupal, and prepupal stages was 97.82, 93.62, 96.42, and 97.03%, respectively. The average duration of the egg, larval, pupal, and pre-pupal stages was 4.00, 16.18, 1.58, and 9.17 d, respectively. During the larval stage, 43.44% of females passed through seven instars, observing that the female's development was significant slower than males. The female larvae that developed through six and seven instars exhibited a mean growth rate of 1.52 and 1.44, respectively. Female pupae were significantly larger, exhibiting faster development than males. The rearing method proved to be adequate, providing more detailed observations of the biological cycle, especially at the larval stage, and resulting in an overall survival of almost 85%. Two hundred two plant species belonging to 58 families are listed as natural hosts for S. eridania, mainly including Asteraceae, Fabaceae, Solanaceae, Poaceae, Amaranthaceae, and Malvaceae.
Subject(s)
Feeding Behavior , Life Cycle Stages/physiology , Magnoliopsida/parasitology , Spodoptera/growth & development , Animals , Body Weight , Female , Host-Parasite Interactions , Larva/growth & development , Male , Pupa/growth & development , Sex Factors , Spodoptera/anatomy & histology , Spodoptera/physiologyABSTRACT
Biotic potential and reprodutcive parameters of Spodoptera eridania (Stoll) (Lepidoptera, Noctuidae) in the laboratory: This study aimed to evaluate the biotic potential and reproductive parameters of Spodoptera eridania (Stoll, 1782) under controlled conditions (25 ± 1ºC, 70 ± 10% RH and 14 hour photophase). The longevity, pre-, post- and oviposition periods, fecundity and fertility of 15 couples was evaluated. The longevity of females (10.80 days) was not significantly higher than those of males (9.27 days). The mean durations of the pre, post and oviposition periods were 2.067, 0.600 and 8.133 days, respectively. The mean fecundity per female was 1,398 eggs and the mean fertility was 1,367.50 larvae. On average, females copulated 1.133 times. A strong positive correlation was observed between the number of mating and fecundity (r = 0.881, P <0.001). However a strong negative correlation was observed between the number of copulations and the duration of the pre-oviposition period (r = -0.826, P = 0.002) and longevity (r = -0.823, P = 0.001). The biotic potential of S. eridania was estimated at 1.894 x 10(25) individuals/female/year. The net reproductive rate (Ro) was 560.531 times per generation and the mean generation time (T) was 35.807 days. The intrinsic rate of increase (rm) was 0.177, with a finite rate of increase (l) of 1.193, per week.
ABSTRACT
The chemical composition of the soybean pods armyworm Spodoptera cosmioides (Walker, 1858) (Lepidoptera: Noctuidae) and Anticarsia gemmatalis Hübner, 1818 (Lepidoptera: Erebidae) larval cuticles was evaluated using gas chromatography coupled to a mass detector (GC-MS). Among the usual lipids found in the insect cuticle, α-tocopherol and α-tocopheryl acetate were also isolated from S. cosmioides. On the other hand, no vitamin E derivative was found in A. gemmatalis exuvia. This is the first report of vitamin E occurrence in the insect's cuticle.
Subject(s)
Glycine max , Spodoptera/chemistry , alpha-Tocopherol/analysis , Animals , Gas Chromatography-Mass SpectrometryABSTRACT
Leaves of Palicourea marcgravii were extracted successively with hexane, ethyl acetate and ethanol in order to evaluate their acaricidal activity on larvae and adult stages of the cattle tick Rhipicephalus (Boophilus) microplus. The ethyl acetate extract showed the highest bioactivity of the tested extracts, which contained 0.12% monofluoroacetic acid. On engorged female, the ethyl acetate extract showed a lethal concentration 50% - LC(50)=30.08 mg ml(-1), inhibitory concentration 50% - IC(50)=5.79 mg ml(-1) and lethal time 50% - LT(50)=4.72 days; 100% reproduction was controlled at concentrations of 50 mg ml(-1) and on larvae the ethyl acetate extract showed a LC(50)=2.46 mg ml(-1). No alkaloids were detected in any of the extracts. This is the first report on the acaricidal activity of P. marcgravii extracts against R. microplus as well as the acaricidal properties of a plant species containing monofluoroacetic acid.
Subject(s)
Acaricides/pharmacology , Plant Extracts/pharmacology , Rhipicephalus/drug effects , Rubiaceae/chemistry , Acaricides/chemistry , Animals , Dose-Response Relationship, Drug , Female , Plant Extracts/chemistryABSTRACT
The wood protective action of citrus wax, a waste from the citrus industry that is a mixture of citrus fruit epicuticular waxes and essential oils, was evaluated against the termite Cryptotermes brevis Walker (Isoptera: Kalotermitidae). The antifeedant index (AI) of the total wax and fractions was calculated. The total citrus wax exhibited an AI50 value of 24.69 mg/cm³, the wax after hydrodistillation showed the strongest antifeedant property (AI50 11.68 mg/cm³). Fractionation of the wax and gas chromatography-mass spectrometric analysis allowed the identification of coumarins and furancoumarins as the active compounds. These results suggest the potential use of these industrial residues as a natural approach to termite control.
Subject(s)
Citrus , Feeding Behavior/drug effects , Isoptera/drug effects , Oils, Volatile/pharmacology , Waxes/pharmacology , Animals , Waxes/chemistryABSTRACT
Nomuraea rileyi represents an important natural control agent of Anticarsia gemmatalis preventing populations from reaching economic threshold levels in soybean. During the processes of host infection, entomopathogenic fungi produce extracellular proteases, which degrade the host cuticle and are suggested to be virulence determinants. It was examined the production of subtilisin-like (Pr1) and trypsin-like (Pr2) proteases in two strains (NR458 and CG434) of N. rileyi and its possible role in the process of pathogenicity to this caterpillar. Fungal growth was performed in a mineral medium containing nitrate, and supplemented with the cuticle or exuviae from A. gemmatalis, or with the non-cuticular substrate casein. In medium containing nitrate as sole nitrogen source, no detectable Pr1-like activity occurred in the culture supernatants of the two fungal strains. However, both strains of N. rileyi produced Pr1-like protease in all medium amended with exogenous nitrogen source, and it was highly expressed in the presence of insect cuticle. Pr2-like activity was significantly inferior to Pr1-like activity and it was detected only in some of the media culture and incubation periods tested. In the NR458 culture supernatant the highest activity was observed in medium containing nitrate as nitrogen source. Correlation analysis between the percentage of A. gemmatalis mortality in bioassays and Pr1-like protease activity of strain NR458 suggests a positive correlation for these variables.
O objetivo deste estudo foi avaliar a produção de proteases dos tipos subtilisina [Pr1] e tripsina [Pr2] por duas linhagens do fungo entomopatogênico Nomuraea rileyi e a correlação entre a atividade de Pr1 e a patogenicidade contra Anticarsia gemmatalis. O crescimento do fungo foi realizado em meio mínimo contendo nitrato e suplementado com a cutícula ou exúvia de A. gemmatalis, ou com substrato não cuticular caseína. Em meio contendo nitrato, nenhuma atividade de Pr1 foi detectada nos sobrenadantes das culturas. Entretanto, as duas linhagens de N. rileyi produziram Pr1 em meio suplementado com fonte exógena de nitrogênio, e alta atividade foi verificada na presença da cutícula do inseto. A atividade de Pr2 foi inferior à atividade de Pr1. A análise de correlação entre a atividade de Pr1 da linhagem NR458 e mortalidade de A. gemmatalis sugere uma correlação positiva para essas variáveis. A avaliação da atividade de enzimas em diferentes condições pode ajudar na compreensão do processo infeccioso de N. rileyi em A. gemmatalis.
ABSTRACT
The mortality of 14-21-day-old Rhipicephalus (Boophilus) microplus larvae, and the mortality and fertility of groups of engorged adult females exposed to different concentrations of hexane, ethyl acetate and ethanol extracts of spiked pepper (Piper aduncum) were evaluated, using a completely randomized design with five treatment groups, two control groups, and two replicates for the larvae and five replicates for the adult females. Similar methodology was used to investigate the toxicity of the essential oil hydro-distillate (94.84% dillapiole) obtained from the P. aduncum crude hexane extract. The LC(50) of the hexane extract was 9.30 mg ml(-1) for larvae and the reproduction reduction ranged from 12.48% to 54.22%, while 0.1mg/ml(-1) of the essential oil induced 100% mortality in larvae. Literature reports on natural products active against R. microplus were listed and compared with the results presented here. These results indicate that P. aduncum extracts, and particularly its essential oil, are potential alternative control agents for R. microplus.
Subject(s)
Piper/chemistry , Plant Extracts/pharmacology , Rhipicephalus/drug effects , Animals , Brazil , Female , Larva/drug effects , Oils, Volatile/chemistry , Oils, Volatile/pharmacology , Ovum/drug effects , Plant Extracts/chemistry , Plant Oils/chemistry , Plant Oils/pharmacology , TreesABSTRACT
Ribosome-inactivating proteins (RIPs) from plants inhibit protein synthesis by inactivating ribosomes. Some two-chain (type 2) RIPs are highly toxic and may play a role in plant defense. The lower toxicity of single-chain (type 1) RIPs reflects the lack of a protein domain able to bind to, and translocate the toxin across cell membranes. We studied the effect of single-chain RIPs, lychnin, momordin, gelonin, PAP-S and saporin S-6, in larvae of Anticarsia gemmatalis and Spodoptera frugiperda. After ingesting a total dose of 20 or 40 microg of the toxins, weight gain, survival rate, lesions in DNA and oxidative status (catalase and superoxide dismutase activities and lipidic peroxidation) of RIP-treated insects were assayed. Momordin was the less toxic in the biossays. S. frugiperda had a more pronounced weight loss on the 4th day of treatment and A. gemmatalis on the 10th day. RIP-induced mortality reached 57.13% for A. gemmatalis and 29.45% for S. frugiperda. RIP-treated insects showed a 2-3-fold increase in DNA lesions as assessed by the comet assay, but there were no correlations between stress markers and DNA damage. We conclude that single-chain RIPs are entomotoxic to lepidopteran insects causing extensive DNA lesions.
Subject(s)
Moths/drug effects , Ribosome Inactivating Proteins, Type 1/pharmacology , Animals , Catalase/metabolism , DNA Damage/drug effects , Larva/drug effects , Larva/enzymology , Lipid Peroxidation , Moths/enzymology , Plant Proteins/pharmacology , Ribosome Inactivating Proteins/pharmacology , Saporins , Superoxide Dismutase/metabolism , Weight Gain/drug effectsABSTRACT
Este fungo foi isolado pela primeira vez de lagartas de L. obliqua de uma agregação em plátano (Platanus acerifolia (Aiton) Wild - Platanaceae), em Bento Gonçalves, RS, Brasil. Após isolamento, purificação e caracterização, realizou-se um teste de patogenicidade com lagartas sadias de L. obliqua para corroborar, sua infectividade pelo postulado de Koch. Constatou-se correspondência morfológica e molecular entre o inóculo e o reisolado, comprovando sua patogenicidade a L. obliqua.
It is recorded for the first time the occurrence of the entomopathogenic fungus Isaria javanica (Frieder. & Bally) Samson & Hywell-Jones (Fungi: Sordariomycetes) infecting Lonomia obliqua Walker (Lepidoptera: Saturniidae: Hemileucinae) caterpillars. This fungus was isolated from L. obliqua individuals collected from Platanus acerifolia (Aiton) Wild- Platanaceae in Rio Grande do Sul state, Brazil. After isolation, purification and characterization, fungal conidia were inoculated on healthy L. obliqua caterpillars and from dead caterpillars the fungal isolates were again obtained. New isolates and the original isolate did not differ when compared by morphological and molecular tests.
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Beauveria bassiana is a well-known broad-range arthropod pathogen which has been used in biological control of several pest insects and ticks such as Boophilus microplus. Beauveria amorpha has both endophytic and entomopathogenic characteristics, but its capacity for biological control has still not been studied. During the processes of host infection, B. bassiana and B. amorpha produce several hydrolytic extracellular enzymes, including proteases and chitinases, which probably degrade the host cuticle and are suggested to be pathogenicity determinants. To access the role of these enzymes during infection in the tick B. microplus, we analyzed their secretion during fungus growth in single and combined carbon sources, compared to complex substrates such as chitin and B. microplus cuticle. Chitin and tick cuticle-induced chitinase in both fungus and protease was induced only by tick cuticle. SEM analysis of B. amorpha and B. bassiana infecting B. microplus showed apressorium formation during penetration on cattle tick cuticle.
Subject(s)
Ascomycota/enzymology , Chitinases/metabolism , Peptide Hydrolases/metabolism , Pest Control , Ticks/microbiology , Animals , Ascomycota/isolation & purification , Ascomycota/ultrastructure , Chitin/metabolism , Ticks/ultrastructureABSTRACT
Um grande número de fungos são conhecidos como produtores de metabólitos secundários, ativos sobre diversos organismos vivos, provocando inibição de crescimento, doenças e posteriormente sua morte. Diversos estudos mostraram que o fungo Nomuraea rileyi, é um produtor de metabólitos ativos sobre insetos e microrganismos mostrando atividade inseticida sobre larvas de Bombyx mori. O propósito deste trabalho foi analisar a atividade mutagênica de um metabólito produzido pelo fungo Nomuraea rileyi, sobre as linhagens TA98 e TA100 de Salmonella thiphymurium. A análise estatística dos resultados obtidos indicou claramente a ausência de mutagenicidade para o metabólito produzido pelo fungo Nomuraea rileyi. O metabólito, não induz a mutações de substituições de pares de base e frameshift como demonstrado pelos testes de genotoxicidade...
Subject(s)
Animals , Fungi , Mutagenesis , Carcinogens , Salmonella typhimuriumABSTRACT
The characterization of entomopathogenic microorganisms is important for the selection of more effective strains for use in integrated pest-control programs. Five Nomuraea rileyi strains (SA86101, GU87401, SR86151, CG128 and VA9101) were characterized using random amplified polymorphic DNA (RAPD) analysis, virulence studies and assessment of chitinolytic and proteolytic activity. RAPD analysis divided the strains into two groups with a similarity coefficient of 0,76 percent, group 1 consisting of strains SA86101, GU87401 and SR86151 and group 2 of strains CG128 and VA9101. The LT50 varied from 165h with strain VA9101 to 246h with strain GU87401. Chitinolytic and proteolytic activity of the fungi after 144h growth in minimal medium were tested using colloidal chitin as substrate. All strains exhibited enzyme activity, with strain VA9101 having the highest chitinase activity (0,0040 mumol/mL/min the 40ºC) and strain SA86101 the highest proteolytic activity. No relationship was found between RAPD analysis, virulence and chitinase or protease activity
ABSTRACT
Metabólitos do fungo entomopatogênico Nomuraea rileyi produzidos em culturas submersas em caldo Sabouraud sacarose extrato de levedura foram extraídos com diclorometano. O extrato bruto foi fracionado por cromatografia em coluna e em camada espessa de fluxo contínuo utilizando benzeno-clorofórmio-acetato de etila 18:1:1 (v:v:v) como eluentes. Amostras de Saccharomyces cerevisiae e de bactérias (18 cepas hospitalares e 5 estirpes fitopatogênicas) foram testadas frente ao metabólito empregando-se o método de difusäo em ágar pelo sistema de discos (Kirby-Bauer). Aproximadamente (40 por cento) (9/23) das amostras bacterianas ensaiadas tiveram seu crescimento inibido na presença do metabólito produzido pelo fungo Nomuraea rileyi, sugerindo uma possível atividade antibacteriana deste metabólito
Subject(s)
Antifungal Agents/metabolism , Gram-Negative Bacteria/growth & development , Gram-Positive Bacteria/growth & development , Mitosporic Fungi/isolation & purification , MycotoxinsABSTRACT
O presente trabalho foi conduzido com a finalidade de avaliar a virulência de conídios de três linhagens do fungo Nomuraea rileyi produzidos em arroz, sorgo e soja estocados por 3 meses a 4°C. Verificou-se que conídios armazenados apresentaram baixas taxas de mortalidade de Anticarsia gemmatalis.
The present work was carried out aiming to estimate the conidia virulence of three strains of Nomuraea rileyi fungi. Conidia produced in rice, sorghum and soybean was stored at 4°C for three months. It was observed that stored conidia caused the Anticarsia gemmatalis death rate reduction.
ABSTRACT
Este trabalho teve o objetivo de avaliar a açäo de alguns agrotóxicos sobre o fungo entomopatogênico Nomuraea rileyi, sendo utilizados, para isso, sete inseticidas, um fungicida e um herbicida. O estudo foi realizado em placas contendo agrotóxicos em comparaçäo com placas de controle. Através da análise estatística dos resultados foi possível verificar diferenças significativas entre os agrotóxicos e doses testadas, enquanto que entre as linhagens näo foram verificadas diferenças significativas
