1,689 research outputs found

    Identification of Fungal Pathogens of Grasshoppers

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    Effect of Conidia Germination on Infection of Brown Planthopper (BPH) by Insect Fungi

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    Conidia of insect fungi actively invade BPH [brown planthopper]. After a conidium lands on the insect cuticle, germination takes about 8 to 16 h, depending on the temperature and relative humidity. After the germination, tuber is formed, the conidium produces specific chitinase enzymes to dissolve the insect cuticle. This allows the fungus to enter the insect body cavity, where further fungus growth occurs. At the end of the infection cycle, the mycelium sporulates on the outside of the insect. Conidia produced on the cadaver can infect healthy BPH initiating epizootics of the fungus. To test infection, 50 adult alate BPH were used for treatment. Insect were dipped in the conidia solution for about 60s and transferred to filter paper to drain. Control insects were dipped in Tween 80 solution. Insects were incubated on potted rice plants in mylar cages. Half the cages were covered with plastic bags for 2.5 h immediately after fungi application to raise RH to saturation. All pots were kept in a greenhouse at 25-30 deg C (day) and 15-20 deg C (night) for 5 d. Live and infected (dead and fungi-covered) insects were counted. Mortality due to fungus infection was calculated. The results show lessening, but not significantly different mortality with increasing fungus conidia treatment. Pregermination of the fungus Beauveria bassiana conidia and 2 h incubation at saturated RH did not increase BPH infection

    A Radio Transient 0.1 pc from Sagittarius A*

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    We report the discovery of a transient radio source 2.7 arcsec (0.1 pc projected distance) South of the Galactic Center massive black hole, Sagittarius A*. The source flared with a peak of at least 80 mJy in March 2004. The source was resolved by the Very Large Array into two components with a separation of ~0.7 arcsec and characteristic sizes of ~0.2 arcsec. The two components of the source faded with a power-law index of 1.1 +/- 0.1. We detect an upper limit to the proper motion of the Eastern component of ~3 x 10^3 km s^-1 relative to Sgr A*. We detect a proper motion of ~10^4 km s^-1 for the Western component relative to Sgr A*. The transient was also detected at X-ray wavelengths with the Chandra X-ray Observatory and the XMM-Newton telescope and given the designation CXOGC J174540.0-290031. The X-ray source falls in between the two radio components. The maximum luminosity of the X-ray source is ~10^36 erg s^-1, significantly sub-Eddington. The radio jet flux density predicted by the X-ray/radio correlation for X-ray binaries is orders of magnitude less than the measured flux density. We conclude that the radio transient is the result of a bipolar jet originating in a single impulsive event from the X-ray source and interacting with the dense interstellar medium of the Galactic Center.Comment: accepted in ApJ; 24 pages; 8 figure

    Precision Farming by Cotton Producers in Eleven Southern States: Results from the 2005 Southern Precision Farming Survey

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    Precision Farming by Cotton Producers in Eleven Southern States: Results from the 2005 Southern Precision Farming Surveycotton, precision farming, survey, Agribusiness, Farm Management, Production Economics, Research and Development/Tech Change/Emerging Technologies,

    Precision Farming by Cotton Producers in Six Southern States: Results from the 2001 Southern Precision Farming Survey

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    Precision Farming by Cotton Producers in Six Southern States: Results from the 2001 Southern Precision Farming Surveycotton, precision farming, survey, Agribusiness, Farm Management, Production Economics, Research and Development/Tech Change/Emerging Technologies,

    Occurrence of Entomophthorales on Spittlebugs Pests of Pasture in Eastern São Paulo State, Brazil

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    Spittlebugs (Hemiptera: Cercopidae) are the most important pests of pasture in Brazil. Nymphal behavior, i.e. residing in the soil, makes their control with insecticides difficult. Although Entomophthorales fungi occasionally have been found at epizootic levels in spittlebug populations, they have not been cultured, had their incidence levels determined, nor evaluated for pest control potential. The research reported here aimed to evaluate the occurrence of Entomophthorales species on spittlebug pests of pasture in Pindamonhangaba County, São Paulo State, Brazil. Evaluations were carried out in 2 adjacent fields with Brachiaria decumbens and Pennisetum purpureum grasses, respectively, of 5 ha each. Evaluations were done every 4 days from January through February by capturing spittlebug adults on leaves with an entomological sweep net, and the insect samples were kept frozen until examined. Insect abdomens were dissected and observed by microscopy for the presence of hyphae and resting spores. Insects cadavers with sporulating fungus were collected in the field and taken immediately to the lab to isolate the pathogen. Scanning electron microscopy pictures were taken of conidophores, and primary and secondary conidia of both fungi. Furia sp. was found at epizootic levels on Deois schach in the Brachiaria pasture, reaching 80% infected followed by a fall in the insect population. Batkoa sp. was found at enzootic levels (\u3c 10% infected) on Mahanarva fimbriolata in the P. purpureum pasture. Furia sp. also was found to infect another important spittlebug, Deois flavopicta, indicating that it has good potential as a bioinsecticide. Heavy rainfall adversely affected the occurrence of Batkoa sp. in M. fimbriolata populations in P. purpureum pasture

    Hungry for change: the Sydney Food Fairness Alliance

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    The Sydney Food Fairness Alliance is one of a growing number of nascent food movements in Australia to have emerged out of concern for the country’s food future, as well as the deleterious effect the present food system is having on its citizens’ health and the continent’s fragile environment. The Alliance’s structure and activities clearly position it as a new social movement (NSM) engaged in collective action on a specific issue, in this instance, food security/justice, and operating outside the political sphere while aiming to influence and affect societal change. Food security as a human right lies at the heart of the Alliance’s philosophy, and equitable, sustainable food policies for New South Wales are a core focus of its advocacy work. The authors argue that the Alliance is a distinctive food movement in that it positions itself as an \u27umbrella\u27 organization representing a wide range of stakeholders in the food system. This chapter reflects on the values, achievements, issues of concern, strengths and weaknesses, and future of the Sydney Food Fairness Alliance. This resource is Chapter 8 in \u27Food Security in Australia: Challenges and Prospects for the Future\u27 published by Springer in 2013

    An evidence-based definition of anemia for singleton, uncomplicated pregnancies

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    BACKGROUND: The definition for anemia in pregnancy is outdated, derived from Scandinavian studies in the 1970\u27s to 1980\u27s. To identity women at risk of blood transfusion, a common cause of Severe Maternal Morbidity, a standard definition of anemia in pregnancy in a modern, healthy United States cohort is needed. OBJECTIVE: To define anemia in pregnancy in a United States population including a large county vs. private hospital population using uncomplicated patients. MATERIALS AND METHODS: Inclusion criteria were healthy women with the first prenatal visit before 20 weeks. Exclusion criteria included preterm birth, preeclampsia, hypertension, diabetes, short interval pregnancy (\u3c18 months), multiple gestation, abruption, and fetal demise. All women had iron fortification (Ferrous sulfate 325 mg daily) recommended. The presentation to care and pre-delivery hematocrits were obtained, and the percentiles determined. A total of 2000 patients were included, 1000 from the public county hospital and 1000 from the private hospital. Each cohort had 250 patients in each 2011, 2013, 2015, and 2018. The cohorts were compared for differences in the fifth percentile for each antepartum epoch. Student\u27s t-test and chi-squared statistical tests were used for analysis, p-value of ≤0.05 was considered significant. RESULTS: In the public and private populations, 777 and 785 women presented in the first trimester while 223 and 215 presented in the second. The women at the private hospital were more likely to be older, Caucasian race, nulliparous, and present earlier to care. The fifth percentile was compared between the women in the private and public hospitals and were clinically indistinguishable. When combining the cohorts, the fifth percentile for hemoglobin/hematocrit was 11 g/dL/32.8% in the first trimester, 10.3 g/dL/30.6% in the second trimester, and 10.0 g/dL/30.2% pre-delivery. CONCLUSIONS: Fifth percentile determinations were made from a combined cohort of normal, uncomplicated pregnancies to define anemia in pregnancy. Comparison of two different cohorts confirms that the same definition for anemia is appropriate regardless of demographics or patient mix

    Risk Factors Associated with False Positive HIV Test Results in a Low-Risk Urban Obstetric Population

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    Objective. To examine risk factors for false positive HIV enzyme immunoassay (EIA) testing at delivery. Study Design. A review of pregnant women who delivered at Parkland Hospital between 2005 and 2008 was performed. Patients routinely received serum HIV EIA testing at delivery, with positive results confirmed through immunofluorescent testing. Demographics, HIV, hepatitis B surface antigen (HBsAg), and rapid plasma reagin (RPR) results were obtained. Statistical analyses included Pearson's chi-square and Student's t-test. Results. Of 47,794 patients, 47,391 (99%) tested negative, 145 (0.3%) falsely positive, 172 (0.4%) positive, and 86 (0.2%) equivocal or missing HIV results. The positive predictive value of EIA was 54.3%. Patients with false positive results were more likely nulliparous (43% versus 31%, P < 0.001) and younger (23.9 ± 5.7 versus 26.2 ± 5.9 years, P < 0.001). HIV positive patients were older than false positive patients and more likely positive for HBsAg and RPR. Conclusion. False positive HIV testing at delivery using EIA is associated with young maternal age and nulliparity in this population

    Fate of Biological Control Introductions: Monitoring an Australian Fungal Pathogen of Grasshoppers in North America

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    In North America there are two generally recognized pathotypes (pathotypes 1 and 2) of the fungus Entomophaga grylli which show host-preferential infection of grasshopper subfamilies. Pathotype 3, discovered in Austra- lia,hasabroadergrasshopperhostrangeandwasconsidered to be a good biocontrol agent. Between 1989 and 1991 patho- type3wasintroducedattwofieldsitesinNorthDakota.Since resting spores are morphologically indistinguishable among pathotypes, we used pathotype-specific DNA probes to con- firm pathotype identification in E. grylli-infected grasshop- pers collected at the release sites in 1992, 1993, and 1994. In 1992, up to 23% of E. grylli-infected grasshoppers of the subfamilies Melanoplinae, Oedipodinae, and Gomphocerinae were infected by pathotype 3,with no infections \u3e1 km from the release sites. In 1993, pathotype 3 infections declined to 1.7%. In 1994 grasshopper populations were low and no pathotype3infectionswerefound.Thefrequencyofpathotype 3 infection has declined to levels where its long-term survival in North America is questionable. Analyses of biocontrol releases are critical to evaluating the environmental risks associatedwiththeseecologicalmanipulations,andmolecular probesarepowerfultoolsformonitoringbiocontrolreleases
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