RESUMO
Centipedegrass,Eremochloa ophiuroides (Munro) Hack, severely inhibits growth of the fall armyworm larva,Spodoptera frugiperda (J.E. Smith). Fresh centipedegrass extracts and extract fractions were deposited on Celufil, incorporated into meridic-based diets and bioassayed against neonate larvae of the fall armyworm in the laboratory. The methanol extract (F1) caused the greatest reduction in larval weight. When F1, was partitioned between méthylene chloride and water, the activity was transferred to the water-soluble fraction (F5), which, when further fractionated using preparative C-18 reverse-phase chromatography, yielded active F7 and F8 fractions. Gas chromatograph-mass spectrometry and high-pressure liquid chromatography (HPLC) showed F7 to be 95% caffeoylquinic acids with chlorogenic acid as the major constituent. HPLC analysis of F8 revealed maysin [2â³-O- α-L-rhamnosyl-6-C-(6-deoxy-Xylo-hexos-4-ulosyl)luteolin] and other luteolin derivatives. Chlorogenic acid and other caffeoylquinic acids, maysin, and other luteolin derivatives are the major factors responsible for the antibiotic resistance of centipedegrass to larvae of the fall armyworm.
RESUMO
Acids found in moth scales of laboratory-rearedHeliothis zea (Boddie) moths are hexanoic, heptanoic, octanoic, nonanoic, 2- (or 3-) furan carboxylic, phenylacetic, benzoic, sorbic, and 4-hydroxybenzoic acid. The last two of these acids are preservatives added to the artifical diet as sorbic acid and methyl-p-hydroxybenzoate. FemaleTrichogramma pretiosum Riley exhibited increased rates of parasitization ofH. zea eggs in the presence of some of these compounds in laboratory experiments. Exposure to a mixture of all of these compounds did not increase parasitization, and the elimination of acids from the crude moth-scale extract did not reduce parasitization by the wasps.
RESUMO
Telenomus remits Nixon is a parasitoid that attacks egg masses ofSpodoptera frugiperda (J.E. Smith). Increased host-seeking behavior was elicited fromT. remus females in Y-tubes, Petri dish, and greenhouse bioassays byS. frugiperda female abdominal tips as well as (Z)-9-tetradecene-1-ol acetate and (Z)-9-dodecene-1-ol acetate.
RESUMO
Volatile chemicals emanating from an excretion (apparently meconium) and abdominal tips of femaleHeliothis zea (Boddie) moths mediated increased rates of parasitization ofH. zea eggs byTrichogramma pretiosum Riley. A blend of synthetic chemicals, consisting of hexadecanal, (Z)-7-hexadecenal, (Z)-9-hexadecenal, and (Z)-11-hexadecenal, which has been identified as the sex pheromone of and from the abdominal tip of femaleH. zea moths, also increased rates of parasitization ofH. zea eggs byT. pretiosum in greenhouse experiments. In addition, parasitization ofH. zea eggs by wildTrichogramma spp., in field plots of cotton,Gossypium hirsutum L., treated with a similar blend of chemicals, in Conrel fibers, was more than double that in untreated plots.
RESUMO
A method is proposed for extraction and cleanup of corn samples for the quantitation of 4 aflatoxins by high pressure liquid chromatography (HPLC). After aqueous methanol extraction, ammonium sulfate treatment, and partition of aflatoxins into chloroform, sample extracts are partially purified on Sep-Pak cartridges or small columns packed with HPLC grade silica; cleanup requires only 13 mL solvent/sample. Aflatoxins B1, B2, G1, and G2 in the purified extract are resolved in ca 10 min by normal phase HPLC on a microparticulate (5 mum) silica gel column with a 50% water-saturated chloroform-cyclohexane-acetonitrile-ethanol solvent, and are measured by ultraviolet fluorescence in a silica gel-packed flowcell. Recoveries of added aflatoxins B1, B2, G1, and G2 were 84-118% at levels of 1.5-125 micrograms/kg.
Assuntos
Aflatoxinas/análise , Zea mays/análise , Cromatografia Líquida de Alta Pressão , Métodos , SolventesRESUMO
Male boll weevils, Anthonomus grandis, held in a light regimen of 16 hours of light and 8 hours of darkness released pheromone rhythmically during the 24 hours. The amount released during peaks was typically 20 times the amount released in valleys. The ratio of the two alcohol components of the pheromone also showed a daily rhythm. Under continuous light, both the release of pheromone and the ratio of the two alcohol components were arrhythmic. In darkness, pheromone release was diminished more than tenfold over the 20-day test period.
Assuntos
Bissinose/etiologia , Gossypium , Álcoois/análise , Aldeídos/análise , Ácidos Graxos/análise , Furanos/análise , Gossypium/análise , Gossypium/fisiologia , Humanos , Hidrocarbonetos/análise , Resíduos Industriais/análise , Cetonas/análise , Piranos/análise , Terpenos/análise , VolatilizaçãoAssuntos
Gossypium , Óleos Voláteis/análise , Álcoois/análise , Derivados de Benzeno/análise , Bissinose/etiologia , Cromatografia Gasosa , Poeira , Éteres Cíclicos/análise , Furanos/análise , Humanos , Hidrocarbonetos/análise , Espectrometria de Massas , Piranos/análise , Vapor , Terpenos/análise , Indústria TêxtilAssuntos
Ácidos Graxos/metabolismo , Insetos , Metabolismo dos Lipídeos , Frações Subcelulares/metabolismo , Envelhecimento , Animais , Núcleo Celular/metabolismo , Cromatografia em Camada Fina , Colorimetria , Citoplasma/metabolismo , Ésteres/metabolismo , Microssomos/metabolismo , Mitocôndrias/metabolismo , Fosfatidilcolinas/metabolismo , Fosfatidiletanolaminas/metabolismo , Fosfolipídeos/metabolismo , Pupa/citologia , Pupa/metabolismo , Esteróis/metabolismoRESUMO
The lipids of larvae, male adults, and female adults of the pecan weevil,Curculio caryae (Horn), were studied, and special attention was given the fatty acid composition. The larvae contained an unusually high amount of lipid material (40.6%), most of it concentrated in the neutral lipid fraction. Male and famale adults contained more conventional quantities, 5.8 and 8.2%, respectively. Oleic acid was the major fatty acid in the total and neutral lipids of all stages; linoleic acid was the most abundant in the phospholipid fractions.
Assuntos
Besouros/metabolismo , Ácidos Graxos não Esterificados/farmacologia , Animais , Relação Dose-Resposta a Droga , Ésteres/farmacologia , Ácidos Graxos Insaturados/farmacologia , Hormônios Juvenis/farmacologia , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Larva/metabolismo , Metanol , Pupa/efeitos dos fármacos , Pupa/crescimento & desenvolvimento , Pupa/metabolismo , Relação Estrutura-Atividade , Fatores de TempoAssuntos
Repelentes de Insetos , Feromônios , Animais , Derivados de Benzeno , Fenômenos Químicos , Química , Cloro , Besouros , Feminino , Glicóis , Masculino , Modelos Químicos , Polietilenos , Fatores de TempoRESUMO
When atmosphere from cotton plants (Gossypium hirsutum L., var. Deltapine Smoothleaf) was condensed by passing it over the expansion coil of an air conditioner and three 1-hour collections per day (early morning, noon, and late afternoon) were made, the total essential oils were found to consist of 50 to 60% beta-bisabolol (I(k) 1660) and gamma-bisabolene (I(k) 1550) and 30 to 40% geraniol (I(k) 1250), myrtenal (I(k) 1328), nerolidol (I(k) 1520), and beta-caryophyllene oxide (I(k) 1590). As the plant matured, trans-2-hexanol was produced in concentrations of 7 to 27%. Before fruiting, beta-bisabolol made up as much as 60% of the total essential oil transpired by the plants, and as the concentration of beta-bisabolol increased, that of gamma-bisabolene decreased.
RESUMO
The response of female boll weevils to males, Anthonomus grandis Boheman, in laboratory bioassays can be reproduced by exposure to a mixture of compounds I, II, and either III or IV, all isolated from male weevils and their fecal material. The same response was elicited by mixtures of tile synthesized coimpounds. Compound I is (+)-cis-2-isopropenyl-l-methylcyclobtutaneethanol; II, cis-3,3-dimethiyl->(1,beta)cyclohexaneethanol; III, cis-3,3-dimethlyl->(1,alpha)-cyclohexaneacetaldehyde; and IV, trans-3,3-dimethyl->(1,alpha)-cyclohexanecetaldehyde.