Compatibility of Chemical Disease and Insect Management Practices Used in New York Vineyards with Biological Control by Anagrus spp. (Hymenoptera: Mymaridae), Parasitoids of Erythroneura Leafhoppers

Toxicity to Anagrus spp. of fungicides and insecticides used in grape production was assessed with laboratory and field bioassays. Field-equivalent rates of fungicides were relatively nontoxic to Anagrus spp. adults in laboratory bioassays. In bioassays with field-weathered residues, sulfur (9600 ppm) caused elevated mortality of adults for 14 to 21 days posttreatment. Residues of microencapsulated methyl parathion (600 and 1200 ppm) increased mortality relative to the control up to 43 days posttreatment. Duration of elevated mortality of adults exposed to carbaryl was dose dependent and ranged from 14 (at 1200 ppm) to >43 days (at 4800 ppm). Residues of carbaryl and methyl parathion applied over parasitized eggs had little effect on emergence, but may have delayed development. In a field trial, adults trapped in carbaryl-treated plots were significantly reduced starting 3 weeks after treatment. Subsequent lower trap catches may have been related to effects of residues on Anagrus spp. adults or to lower leafhopper egg densities in treated plots.     

Evaluation of bioassays to quantifyCylindrocaldium inocula in soil

Leaf discs provided better recovery ofCylindrocladium candelabrum from soil than stem, or twig segments. Leaf discs of eucalypt (Eucalyptus grandis), azalea (Rhododendron sp.), and geranium (Pelargonium sp.) were the best of seven plant baits evaluated. Twig segments of azalea and eucalypt also provided a high percentage of the pathogen recovery, whereas stem segments of pine seedlings (Pinus elliottii) proved unsatisfactory. Although slightly less effective, twig segments were easier to handle than leaf discs which were quickly decomposed in soil. Colonization of eucalypt twig segments byCylindrocladium spp. varied with inoculum level, soil moisture content, and incubation period. The highest percentage of recovery ofC. candelabrum (approx. 95%) was calculated at a field capacity moisture level of 155.9% after 75h of incubation.     

小菜蛾群体繁殖技术

小菜蛾是世界性十字花科蔬菜的主要害虫 ,也是迄今研究认为抗药性发展最快、最为严重的农业害虫。害虫抗药性以及蔬菜害虫防治技术等方面的研究使小菜蛾成为重要的实验昆虫。本文讨论小菜蛾室内群体繁殖技术的几种方法     

Comparative study of the assay of Artemia salina L. and the estimate of the medium lethal dose (LD50 value) in mice, to determine oral acute toxicity of plant extracts

Artemia salina L. (Artemiidae), the brine shrimp larva, is an invertebrate used in the alternative test to determine toxicity of chemical and natural products. In this study the Medium Lethal Concentrations (LC50 value) of 20 plant extracts, Aloe vera (L.) Burm. F. (Aloeaceae), Artemisia absinthium L. (Asteraceae); Citrus aurantium L. (Rutaceae); Cymbopogon citratus (DC. Ex Nees) Stapf (Poaceae); Datura stramonium L. (Solanaceae); Justicia pectoralis Jacq. (Acanthaceae); Musa x paradisiaca L. (Musaceae); Ocimum basilicum L.; O. gratissimum L.; O. tenuiflorum L. (Lamiaceae); Pimenta dioica (L.) Merr. (Myrtaceae); Piper auritum Kunth (Piperaceae); Plantago major L. (Plantaginaceae); Plectranthus amboinicus (Lour.) Spreng. (Lamiaceae); Ruta graveolens L. (Rutaceae); Senna alata (L.) Roxb. (Fabaceae); Stachytarpheta jamaicensis (L.) Vahl (Verbenaceae); and Thuja occidentalis L. (Cupressaceae), were determined using Artemia salina L. (Artemiidae), with the objective of relating the results to the LD50 values reported in mice (tested at three concentrations: 10, 100, and 1000 microg/mL, for each extract). We found good correlation between the in vivo and the in vitro tests (r = 0.85 p < 0.05), and this method is a useful tool for predicting oral acute toxicity in plant extracts.     

Susceptibility of the cattle tick Boophilus microplus (Acari: Ixodidae) to isolates of the fungus Beauveria bassiana

The susceptibility of the tick Boophilus microplus to Beauveria bassiana was evaluated by inoculating eggs, larvae and engorged females of the tick with five fungal isolates at concentrations of 10⁶, 10⁷ and 10⁸ conidia/ml. Tick eggs (0.25 g) were immersed in 1 ml of a suspension of the different conidial concentrations for 1 min. Similar exposure was performed by immersion of 2000 larvae and homogeneous groups of nine engorged females in 2 and 20 ml of conidial suspension, respectively. Treated eggs, larvae and adults were placed in an incubator at 27 ± 1 °C and relative humidity above 80% for evaluation of the fungal action. All fungal isolates applied at all conidial concentrations reduced the hatching rate of larvae from treated eggs by 1.36–65.58% and increased the mortality rate of inoculated larvae by 0.8–70.49%. In the bioassay with engorged females, oviposition period was reduced by 9.69–47.80%, egg mass weight by 4.71–53.87%, estimated reproduction by 8.3–60.62%, egg production index by 5.03–54.20%, percent larval hatching by 0.27–13.96%, and the mortality rate of treated females was increased by 96.60–100%. The reduction of the estimated reproduction obtained for the treated groups ranged from 8.37 to 64.52%. The sporulation of the pathogen on dead females ranged from 3.70 to 88.88% depending on the isolate and concentration used. Isolates AM 09, CB 7 and JAB 07 were the most effective and effectiveness increased with increasing concentrations of conidia in the suspensions.     

Oviposition deterring pheromone in Rhagoletis cerasi: Biological activity of a pure single compound verified in semi-field test

A pure single compound, a palmityl-glucopyranoside identified as component of the oviposition deterring pheromone (ODP) of the European cherry fruit fly was evaluated with respect to its biological activity by means of a semi-field bioassay in a large field-cage with host plants. The comparison of the observed behaviors of flies exposed to clean cherries, to cherries treated with a standard ODP solution and with the pure compound revealed that palmityl-glucopyranoside elicited the same response as did the crude ODP solution. Irritation indices are described that seem to be of use for the characterization of cherry fruit fly behavior in the presence and absence of ODP. The advantages of the field-cage test over the standard laboratory tests are discussed.

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Zusammenfassung Mit zunehmenden Reinigungsschritten am Rohextrakt des Markierungspheromones (ODP) der Kirschenfliege, Rhagoletis cerasi L., und zunehmenden Reinheitsgrad des aktiven Prinzipes nimmt die Menge an Substanz ab, welche sowohl für die chemische Analyse wie auch die Prüfung der biologischen Aktivität zur Verfügung steht. Beim Vorliegen einer nicht mehr wägbaren Menge eines reinen Stoffes im Sommer 1985, welcher als ein Palmityl-glucopyranosid identifiziert werden konnte (Hurter et al., 1987), musste deshalb auf den üblichen Verhaltenstest im Labor verzichtet und ein neuer Lösungsansatz gefunden werden. Nachdem ein erster elektrophysiologischer Test positive Resultate gezeight hatte, wurde die Fraktion Nr. 2634 in einem grossen Freilandkäfig mit Kirschenpflanzen und natürlichen Früchten in einem Verhaltenstest auf ihre biologische Wirksamkeit geprüft.Die in dieser Arbeit präsentierten Resultate zeigen nicht nur, dass mit dem Palmityl-glucopyranosid eine ähnliche Wirkung erzielt wurde wie mit natürlichen ODP, sondern zum erstenmal konnte demonstriert werden, dass in R. cerasi und möglicherweise in andern Fruchtfliegenarten eine einzelne chemische Substanz eine eiablagehemmende Wirkung ausüben kann.

     

Biocidal Potential and Chemical Composition of Industrial Essential Oils from Hyssopus officinalis,Lavandula × intermedia var. Super,and Santolina chamaecyparissus

This work presents the biocidal (insecticidal, ixodicidal, nematicidal, and phytotoxic) effects and chemical compositions of three essential oils obtained from the industrial steam distillation (IEOs) of hyssop (Hyssopus officinalis L.), lavandin (Lavandula × intermedia or L. × hybrida var. Super ), and cotton lavender (Santolina chamaecyparissus L.). Their chemical composition analyzed by gas chromatography coupled to mass spectrometry showed 1,8‐cineole (53%) and β‐pinene (16%) as the major components of H. officinalis, linalyl acetate (38%) and linalool (29%) of L. × intermedia; and 1,8‐cineole (10%) and 8‐methylene‐3‐oxatricyclo[5.2.0.0^2,4]nonane (8%) in S. chamaecyparissus. The biocidal tests showed that L. × intermedia IEO was the most active against the insect Spodoptera littoralis and toxic to the tick Hyalomma lusitanicum, IEO of H. officinalis was strongly active against S. littoralis, and finally, S. chamaecyparissus IEO was a strong antifeedant against the aphid Rhopalosiphum padi, toxic to H. lusitanicum and with moderate effects against Leptinotarsa decemlineata, S. littoralis, and Lolium perenne.     

Influence of chlorophyll concentrations on the reliability of measurements with an oxygen electrode when studying photosynthetic efficiency in bioassays using microalgae

Euglena gracilis and Chlamydomonas reinhardtii were used as model organisms to establish the best conditions for studying photosynthetic efficiency using the Light Pipette – experimental system, which enables sensitive detection of changes in oxygen evolution/consumption and an easy collection and digitalisation of data. Chlorophyll concentrations of 0.005, 0.025, 0.050 and 0.075 mgmL^-1 were investigated using different light regimes. Cultures of E. gracilis at the same chlorophyll concentration absorbed more light(measured at 580 μmol m^-2 s^-1) than those of C. reinhardtii. Cell density had a considerable effect on the reliability of measurements. Chlorophyll concentrations between 0.025 mg_Chl ml^-1 and 0.050 mg_Chlml^-1 can be recommended when applying the Light Pipette system in bioassays using microalgae. This revised version was published online in August 2006 with corrections to the Cover Date.     

Ostreopsis cf. ovata in the Gulf of Gabès (south-eastern Mediterranean Sea): morphological,molecular and ecological characterization

In the last few decades, the frequency of the toxic benthic dinoflagellate Ostreopsis cf. ovata proliferation has increased in the Mediterranean Sea. These blooms are associated with harmful effects on human health and the environment. The present work provides the first long term study on the spatio-temporal distribution of O. cf. ovata in relation to physical parameters in the Gulf of Gabès coastal waters (south-eastern Mediterranean Sea), as well as its morphological, molecular and physiological features. The strains of O. cf. ovata were identified morphologically by light and epifluorescence microscopy. The morphology and the size range of cultured strains were similar to those described regarding O. cf. ovata isolated from the Mediterranean Sea. The ultrastructural analysis of O. cf. ovata cells using the transmission electron microscopy showed the presence of numerous vesicles (VE) containing spirally coiled fibers (SCFs) connected to the mucus canal (CH). The phylogenetic tree based on the internal transcribed spacer region containing the 5.8S rDNA (ITS-5.8S rDNA) revealed that O. cf. ovata strains were placed into the Mediterranean/Atlantic clade. In addition, O. cf. ovata toxicity was evaluated by the mouse bioassay and a dose level ≥ 4 × 10⁴ cells was found to be lethal to mice. The examination of the O. cf. ovata occurrence in the Gulf of Gabès at a large temporal scale (1997–2012) revealed a clear seasonal pattern with dominance from midsummer (July) to late autumn (November). Furthermore, a positive correlation was found between the abundance of O. cf. ovata and salinity, whereas no correlation was found as regards temperature. The occurrence of O. cf. ovata was only detected at salinity above 35 and the highest concentrations were observed at 45. Laboratory experiments confirmed such a result and showed that isolated O. cf. ovata strains had optimal growth at salinity ranging between 35 and 45, with its peak at 40.     

Yeast-based screening of natural product extracts results in the identification of prion inhibitors from a marine sponge

ABSTRACT

One of the major medical challenges of the twenty-first century is the treatment of incurable and fatal neurodegenerative disorders caused by misfolded prion proteins. Since the discovery of these diseases a number of studies have been conducted to identify small molecules for their treatment, however to date no curative treatment is available. These studies can be highly expensive and time consuming, but more recent experimental approaches indicate a significant application for yeast prions in these studies. We therefore used yeast prions to optimize previous high-throughput methods for the cheaper, easier and more rapid screening of natural extracts. Through this approach we aimed to identify natural yeast-prion inhibitors that could be useful in the development of novel treatment strategies for neurodegenerative disorders. We screened 500 marine invertebrate extracts from temperate waters in Australia allowing the identification of yeast-prion inhibiting extracts. Through the bioassay-driven chemical investigation of an active Suberites sponge extract, a group of bromotyrosine derivatives were identified as potent yeast-prion inhibitors. This study outlines the importance of natural products and yeast prions as a first-stage screen for the identification of new chemically diverse and bioactive compounds.