Scalable privacy-preserving data sharing methodology for genome-wide association studies.

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Yu, Fei; Fienberg, Stephen E; Slavković, Aleksandra B; Uhler, Caroline

2014-08-01

The protection of privacy of individual-level information in genome-wide association study (GWAS) databases has been a major concern of researchers following the publication of "an attack" on GWAS data by Homer et al. (2008). Traditional statistical methods for confidentiality and privacy protection of statistical databases do not scale well to deal with GWAS data, especially in terms of guarantees regarding protection from linkage to external information. The more recent concept of differential privacy, introduced by the cryptographic community, is an approach that provides a rigorous definition of privacy with meaningful privacy guarantees in the presence of arbitrary external information, although the guarantees may come at a serious price in terms of data utility. Building on such notions, Uhler et al. (2013) proposed new methods to release aggregate GWAS data without compromising an individual's privacy. We extend the methods developed in Uhler et al. (2013) for releasing differentially-private χ(2)-statistics by allowing for arbitrary number of cases and controls, and for releasing differentially-private allelic test statistics. We also provide a new interpretation by assuming the controls' data are known, which is a realistic assumption because some GWAS use publicly available data as controls. We assess the performance of the proposed methods through a risk-utility analysis on a real data set consisting of DNA samples collected by the Wellcome Trust Case Control Consortium and compare the methods with the differentially-private release mechanism proposed by Johnson and Shmatikov (2013). Copyright © 2014 Elsevier Inc. All rights reserved.

Scalable privacy-preserving data sharing methodology for genome-wide association studies: an application to iDASH healthcare privacy protection challenge.

Science.gov (United States)

Yu, Fei; Ji, Zhanglong

2014-01-01

In response to the growing interest in genome-wide association study (GWAS) data privacy, the Integrating Data for Analysis, Anonymization and SHaring (iDASH) center organized the iDASH Healthcare Privacy Protection Challenge, with the aim of investigating the effectiveness of applying privacy-preserving methodologies to human genetic data. This paper is based on a submission to the iDASH Healthcare Privacy Protection Challenge. We apply privacy-preserving methods that are adapted from Uhler et al. 2013 and Yu et al. 2014 to the challenge's data and analyze the data utility after the data are perturbed by the privacy-preserving methods. Major contributions of this paper include new interpretation of the χ2 statistic in a GWAS setting and new results about the Hamming distance score, a key component for one of the privacy-preserving methods.

Lethal concentration of carbofuran to brown planthopper (Nilaparvata lugens) and green leaf-hopper (Nephotettix virecence)

International Nuclear Information System (INIS)

Kuswadi, A.N.; Sumatra, M.; Anwar, E.; Soekarna, D.

1988-01-01

An oral toxicity test of carbofuran to brown planthopper and green leaf-hopper using sucrose solution as feed given to the hopper through a membrane feeding system was conducted in the laboratory, pure carbofuran was dilute in the feeding solution. The 50 percent lethal concentration (LC-50) of this insecticide to adult and nymph of brown planthopper were 0.21 and 0.43 ppm, respectively, while those to adult and nymph of green leaf-hopper were 0.43 and 0.58 ppm. The LC 90 were 0.56 an 0.90 ppm to adult and nymph of brown planthopper, and 1.20 and 1.60 ppm to adult and nymph of green leaf-hopper, respectively. The brown planthopper was found to be more susceptible than the nymph. When carbofuran was applied to rice plant, this insecticide was accumulated more in the leaf than in the stem, so that green leaf-hopper got more toxicity than the brown planthopper. (authors). 5 refs, 7 figs

METARHIZIUM ANISOPLIAE DAN ANDROGRAPHIS PANICULATA TERHADAP SERANGGA BUKAN HAMA SASARAN

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Dini Yuliani

2016-04-01

Full Text Available The objective of this study was to determine the effect of Metarhizium anisopliae and Andrographis paniculata to the natural enemies of Nephotettix virescens and non-target insect pests. This research was conducted in tungro endemic areas in Subang District, West Java in the wet season 2013/2014. The method of research used a split plot design with four replications. The main plot was IR66, Inpari 9, and Ciherang varieties. Subplot was the application of M. anisopliae, A. paniculata, and control. Observations were carried out five times started at nursery (2 weeks after seedling, 14, 28, 42, and 56 days after planting using insect nets, double swing 10 times on each plot observations. The results show M. anisopliae and A. paniculata not adversely affect on non-target insect pests such as Chironomid and natural enemies of N. virescens namely Lycosa pseudoannulata, Cyrtorhinus lividipennis, Sepedon sp., damselfly, Tipulidae sp., Telenomus sp., dragonfly, and Tetrastichus sp.. Efficacy of M. anisopliae and A. paniculata as one of the control strategies that are environmentally friendly and proved not harmful to non-target insect pests.

Dampak Andrografolid dan Dua Jenis Insektisida Sintetik sebagai Penghambat Makan Nephotettix virescens, terhadap Transmisi Virus Tungro

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I Nyoman Widiarta

1998-07-01

Full Text Available The effect of andrographolide and two synthetic insecticides of pymetrozine and imidacloprid, an antifeedant against N. virescens (Distant, to the rice virus transmission were tested using test tube inoculation method in the green house under natural photoperiod and average temperature of 28.5oC. The root of tungro diseased plant were soaked for 24 hours into tested materials before acquisition feeding to test virus acquisition inhibition, while root of rice seedlings were soaked into tested material for 24 hours before inoculation feeding to test virus inoculation inhibition. The results of studies showed that andrographolide, pymetrozine, and imidacloprid significantly reduced virus acquisition and virus inoculation by N. virescens. Pymetrozine and andrographolide treatments to the tungro diseased plants at concentration of 20 ppm significantly reduced proportion of viruliferous vector to become 17% in average. The increasing concentration into 40 ppm of both materials did not significantly reduce proportion of viruliferous vector. Imidacloprid at concentration of 0.01 and 0.02 ppm, completey inhibited feeding acquisition. Pymetrozine and andrographolide treatment at concentration of 20 ppm to the rice seedlings reduced significantly virus transmission by N. virescens to become 69% in average. The increasing concentration of pymetrozine up to 40 ppm did not reduce virus transmission rate. Imidacloprid at concentration of 0.01 ppm and 0.02 ppm reduced virus transmission to become 25% and 39%, respectively. It was concluded that imidacloprid was the most effective antifeedant reducing virus transmission by N. virescens among tested chemicals. Key words: antifeedant, N. virescens, rice tungro virus disease

Perbandingan Efek Pemberian Bioinsektisida dan Ekstrak Kompos terhadap Produksi Padi Ratun dan Populasi Serangga Hama

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Siti Herlinda

2015-06-01

Full Text Available The advantages of ratooning rice are to save water, cost production, labor, preparation time for planting and harvesting, but the ratooning productivity is still low.  This research aimed to study the effect of the bioinsecticide and compost extract on ratooning rice production and insect populations. The ratooning rice was applied by bioinsecticide, compost extract, and combination of bioinsecticide and compost extract with dose 2 L ha-1  per application, respectively. Data of agronomic variables were statistically analyzed using analysis of variance, whereas insect pest population data were analyzed using Chi Square test. The seedling height of ratoon applied by compost extract was the highest among treatments. The number of productive tillers per clumps and rice production on plot applied by compost extract were higher than the insecticide treatment. At the age of 17 day-ratooning rice, application bioinsecticide reduced the population of insect pests, such as Ciccadulina bipunctata, Recilia dorsalis, Nilaparvata lugens, and Nephotettix nigropictus. Thus, application of compost extract tended to improved the growth and production of the ratooning rice, while the bioinsecticide decreased the insect pest population.Keywords: Beauveria bassiana, rice growth, production

Alarm Pheromone Activity of Nymph-specific Geraniol in Chrysanthemum Lace Bug Corythucha marmorata against Adults and Nymphs.

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Watanabe, Kisaki; Shimizu, Nobuhiro

2015-09-01

The exotic insect pest Corythucha marmorata (Uhler) is increasingly spreading in Japan using the weed Solidago canadensis L. as a major host plant. The nymphs form colonies on the backs of leaves where they crowd together; however, aggregation does not occur in the adults. When an individual nymph is crushed using a needle tip and further the needle tip covered with the nymph's bodily fluids is moved slowly toward the center of the crowd, the surrounding nymphs display an escape behavior and their aggregation is disrupted. We detected geraniol as a nymph-specific volatile component. Bioassay results indicated that geraniol was effective as an alarm pheromone on second to fifth instar nymphs. Furthermore, we found that male and female adults responded sensitively to the alarm pheromone produced by nymphs. These results suggest that although the adult insects do not secrete geraniol, they can detect it produced by nymphs, thereby retaining the ability to escape from danger while suppressing the cost of geraniol production. The present study is the first to demonstrate that an alarm pheromone secreted by nymphs is also effective in adults among Tingidae.

Karakter Populasi Wereng Hijau, Nephotettix virescens (Hemiptera: Cicadellidae di Wilayah Endemi dan Non Endemi Penyakit Tungro Padi

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Supriyadi Supriyadi

2004-12-01

Full Text Available The objectives of this research were to determine the species composition, distribution pattern and virus transmission properties of N. virescens. Sweep net sampling of the leafhopper and others tungro vectors population were conducted from endemic areas in Central Java, East Java and Bali and also non endemic areas from Central Java and East Java. The species composition and distribution pattern of the leafhopper were studied in seedbeds and early stage of rice crop (30 days after transplanting. Inoculation test using Cisadane seedlings was conducted to determine the efficiency of virus transmission by N. virescens colonies. Four tungro virus vectors were found in all areas, namely N. virescens, N. nigropictus, N. malayanus, and Recilia sp. The domination of N. virescens occurred either in the endemic area or the non endemic areas. However, the domination of N. virescens did not correlate with the occurrence of the disease in the endemic area. The distribution pattern of N. virescens was regular. The number of N. virescens active transmitter in the endemic area was higher than that in the non-endemic areas. In addition, the female of N. virescens was more efficient in transmitting the tungro virus than that of the male.

Pertumbuhan Populasi dan Oviposisi Wereng Hijau, Nephotettix virescens Distant (Hemiptera: Cicadellidae Berkaitan dengan saat Padi Keluar Malai

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I Nyoman Widiarta

1996-12-01

more eggs on early maturing variety after flowering stage than that on late maturing variety before flowering stage (p< 0.01; t-test in the pot experiment. Those field and pot experiment facts indicated that the first generation of adult emigrant influenced the population fluctuation in the fields, because the density of predator, Lycosa, was lower in the early maturing variety than in the late maturing variety in the wet season crop of 1994/1995 and it was similar in the dry season crop of 1995.

Geographic and Research Center Origins of Rice Resistance to Asian Planthoppers and Leafhoppers: Implications for Rice Breeding and Gene Deployment

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Finbarr G. Horgan

2017-09-01

Full Text Available This study examines aspects of virulence to resistant rice varieties among planthoppers and leafhoppers. Using a series of resistant varieties, brown planthopper, Nilaparvata lugens, virulence was assessed in seedlings and early-tillering plants at seven research centers in South and East Asia. Virulence of the whitebacked planthopper, Sogatella furcifera, in Taiwan and the Philippines was also assessed. Phylogenetic analysis of the varieties using single-nucleotide polymorphisms (SNPs indicated a clade of highly resistant varieties from South Asia with two further South Asian clades of moderate resistance. Greenhouse bioassays indicated that planthoppers can develop virulence against multiple resistance genes including genes introgressed from wild rice species. Nilaparvata lugens populations from Punjab (India and the Mekong Delta (Vietnam were highly virulent to a range of key resistance donors irrespective of variety origin. Sogatella furcifera populations were less virulent to donors than N. lugens; however, several genes for resistance to S. furcifera are now ineffective in East Asia. A clade of International Rice Research Institute (IRRI-bred varieties and breeding lines, without identified leafhopper-resistance genes, were highly resistant to the green leafhopper, Nephotettix virescens. Routine phenotyping during breeding programs likely maintains high levels of quantitative resistance to leafhoppers. We discuss these results in the light of breeding and deploying resistant rice in Asia.

Uptake of 14C-carbofuran from rice plants by brown planthopper (nilaparvata lugens stal) and green leafhopper (Nephotettix virencence)

International Nuclear Information System (INIS)

Sumatra, M.; Anwar, E.; Kuswadi, A.N.; Soekarna, D.

1988-01-01

An experiment was carried out to determine the amount of 14-C-carbofuran taken up by brown planthopper (BPH) and green leafhopper (GLH) from ride plants containing 14-C-carbofuran. The roots of 30 days old rice plants were immersed in Kimura B solution containing carbofuran (0.6ug/ml) with activity of 18600 pCi/ml. After 3 days, 20 BPH and 20 GLH released onto the rice stems and leaves. The mortalities of BPH and GLH were similar after 24 and 48 hours of the release. The average radioactivity found in living GLH was 3.5 times of those found in living GLH was 3.5 times of those found in living BPH. And in dead GLH was 3.2 times on those in dead BPH. Radioactivity in rice leaves was 3.5 times of those in stems. This layer chromatograph of extracts of Kimura B solution, stems, and leaves showed that small amounts of carbofuran had degraded to substances like 3-OH-carbofuran and 3-keto-carbofuran. The percentage of radioactivity found as carbofuran decreased with time, while the amount of 3-ket-carbofuran increased. (authors). 6 refs, 2 figs, 6 tab

Selectable antibiotic resistance marker gene-free transgenic rice harbouring the garlic leaf lectin gene exhibits resistance to sap-sucking planthoppers.

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Sengupta, Subhadipa; Chakraborti, Dipankar; Mondal, Hossain A; Das, Sampa

2010-03-01

Rice, the major food crop of world is severely affected by homopteran sucking pests. We introduced coding sequence of Allium sativum leaf agglutinin, ASAL, in rice cultivar IR64 to develop sustainable resistance against sap-sucking planthoppers as well as eliminated the selectable antibiotic-resistant marker gene hygromycin phosphotransferase (hpt) exploiting cre/lox site-specific recombination system. An expression vector was constructed containing the coding sequence of ASAL, a potent controlling agent against green leafhoppers (GLH, Nephotettix virescens) and brown planthopper (BPH, Nilaparvata lugens). The selectable marker (hpt) gene cassette was cloned within two lox sites of the same vector. Alongside, another vector was developed with chimeric cre recombinase gene cassette. Reciprocal crosses were performed between three single-copy T(0) plants with ASAL- lox-hpt-lox T-DNA and three single-copy T(0) plants with cre-bar T-DNA. Marker gene excisions were detected in T(1) hybrids through hygromycin sensitivity assay. Molecular analysis of T(1) plants exhibited 27.4% recombination efficiency. T(2) progenies of L03C04(1) hybrid parent showed 25% cre negative ASAL-expressing plants. Northern blot, western blot and ELISA showed significant level of ASAL expression in five marker-free T(2) progeny plants. In planta bioassay of GLH and BPH performed on these T(2) progenies exhibited radical reduction in survivability and fecundity compared with the untransformed control plants.

Estudos bionômicos de Dipetalogaster maximus (Uhler, 1894 (Hemiptera - Triatominae: II - Influência da dieta sobre o ciclo biológico e resistência ao jejum Bionomic studies of Dipetalogaster maximus (Uhler, 1894 (Hemiptera: Triatominae: II. Influence of diet on the biological cycle and resitance to fast

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Jane Margaret Costa

1987-03-01

Full Text Available Avaliou-se a influência de dois tipos de dieta na cronologia da ontogênsese de Dipetalogaster maximus. Alimentou-se um grupo em sangue de camundongos normais (C e outro em sangue de pombos (P. Ambos foram mantidos em estufa B.O.D. a 28ºC e 65% U.R. O grupo alimentado em C, atingiu a fase adulta com X=130,1 dias e o grupo alimentado em P com X=145,68 dias. A percentagem total de mortalidade foi significativamente superior nos alimentados em P (63,71% em relação aos alimentados em C (31,18%. Quanto á resistência ao jejum, o período de sobrevivência foi acentuadamente maior para o grupo alimentado em C. Principalmente nos 3º, 4º e 5º estádios. Estas observações complementam nossos registros anteriores desta espécie, mantida nas mesmas condições, sobre: fertilidade das fêmeas, ritmo de postura, viabilidade dos ovos e curva da mortalidade x fertilidade.Two kinds of blood-meal were assayed in order to broaden the knowledge of the biology of Dipetalogaster maximus: one group of insects was fed on normal mouse blood (C and another group fed on pigeon blood (P. Both groups were kept in a B.O.D. - chamber (28ºC and 65% R.H.. Significant data concerning their development was registered: the group fed on C reached the adult stage in X = 130,1 days and the group fed on P in X = 145,6 days. Mortality of group fed on P, (63,71% was doubled that of group fed on C (31,18%. The period of survival, as measured by resistance to starvation, was markedly greater in group fed on C, particularly in the third, fourth and fifth stages. These observations complete our former records of this species, kept under the same conditions of female fertility, egg vialbility and comparative mortality and fertility rates.

Laboratory bioassays to estimate the lethal and sublethal effects of various insecticides and fungicides on Deraeocoris brevis (Hemiptera: Miridae).

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Amarasekare, K G; Shearer, P W

2013-04-01

This laboratory bioassay focused on lethal and sublethal effects of five insecticides (chlorantraniliprole, cyantraniliprole, spinetoram, novaluron, and lambda-cyhalothrin) and two fungicide treatments (sulfur and a mixture of copper hydroxide and mancozeb) on the predatory mired bug, Deraeocoris brevis (Uhler) (Hemiptera: Miridae) using second instars and adult males and females. Formulated pesticides were tested using concentrations that were equivalent to the high label rate (1x) (high rate) and 1/10th of that amount (0.1x) (low rate) dissolved in 378.5 liters of water. Lambda-cyhalothrin was highly toxic to D. brevis nymphs and adults at both rates, whereas both rates of novaluron were highly toxic to nymphs. Cyantraniliprole, chlorantraniliprole, and novaluron were less toxic to adults, and chlorantraniliprole and spinetoram were less toxic to nymphs. Both rates of spinetoram caused significant mortality to adults. Fecundity of adult females was affected negatively by the high rates of either novaluron or spinetoram, whereas the fertility was affected only by the high rate of novaluron. The high rate of spinetoram reduced survival of nymphs. Adults treated with spinetoram had reduced longevity. Cyantraniliprole caused some mortality to nymphs and affected their survival. Both rates of sulfur were toxic to nymphs and affected emergence to adults. The mixture of copper hydroxide and mancozeb was less toxic to D. brevis. Neither adult longevity nor sex ratio was affected by the fungicides. The r values for D. brecis treated with lambda-cyhalothrin, novaluron, spinetoram, and sulfur were low, indicating that these products may have negative impact on population growth.

Patogenisitas Virus Tungro pada Varietas Tetua Padi Tahan Tungro

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R Heru Praptana

2014-08-01

Full Text Available Tungro is one of the major diseases in rice which has become a constraint in increasing rice production in Indonesia. Tungro is caused by infection of two different viruses, i.e. Rice tungro bacilliform virus (RTBV and Rice tungro spherical virus (RTSV, both of which can only be transmitted by green leafhoppers Nephotettix virescens (Distant in a semipersistent manner. Since there is an indication of the existance of virulence variation of tungro viruses from different areas and the specific relationship between resistance of varieties and tungro viruses isolates, it is important to study the pathogenicity of tungro viruses from some endemic areas in Indonesia. This study aimed to identify the pathogenicity of tungro viruses from several endemic areas in Indonesia in some resistant varieties. One susceptible variety i.e. TN1 and ten resistant varieties were used in the study. Surveys and collection of infected plants and green leafhoppers were done in tungro endemic areas, namely West Java, Central Java, Yogyakarta, Central Sulawesi, West Sulawesi, South Sulawesi, Bali and West Nusa Tenggara. Artificial transmission using the test tube method was used in the pathogenicity test. Green leafhoppers caught from the field were used as transmitters.. The pathogenicity of tungro viruses were identified by the values of the incidence of tungro and the diseases indexes (DI. The result showed that difference in pathogenicity of tungro viruses in some resistant varieties was observed. Isolates from Central Java, Central Sulawesi and West Nusa Tenggara were able to infect all of resistant varieties and the pathogenicity of Central Java isolate was the highest among the other isolates.

Weedy hosts and prevalence of potential leafhopper vectors (Hemiptera: Cicadellidae) of a phytoplasma (16SrIX group) associated with Huanglongbing symptoms in citrus groves.

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Marques, R N; Teixeira, D C; Yamamoto, P T; Lopes, J R S

2012-04-01

Huanglongbing (HLB) is a severe citrus (Citrus spp.) disease associated with the bacteria genus Candidatus Liberibacter, detected in Brazil in 2004. Another bacterium was found in association with HLB symptoms and characterized as a phytoplasma belonging to the 16SrIX group. The objectives of this study were to identify potential leafhopper vectors of the HLB-associated phytoplasma and their host plants. Leafhoppers were sampled every other week for 12 mo with sticky yellow cards placed at two heights (0.3 and 1.5 m) in the citrus tree canopy and by using a sweep net in the ground vegetation of two sweet orange, Citrus sinensis (L.) Osbeck, groves infected by the HLB-phytoplasma in São Paulo state. Faunistic analyses indicated one Agalliinae (Agallia albidula Uhler) and three Deltocephalinae [Balclutha hebe (Kirkaldy), Planicephalus flavicosta (Stål), and Scaphytopius (Convelinus) marginelineatus (Stål)] species, as the most abundant and frequent leafhoppers (Hemiptera: Cicadellidae). Visual observations indicated an association of leafhopper species with some weeds and the influence of weed species composition on leafhopper abundance in low-lying vegetation. S. marginelineatus and P. flavicosta were more frequent on Sida rhombifolia L. and Althernantera tenella Colla, respectively, whereas A. albidula was observed more often on Conyza bonariensis (L.) Cronq. and B. hebe only occurred on grasses. DNA samples of field-collected S. marginelineatus were positive by polymerase chain reaction and sequencing tests for the presence of the HLB-phytoplasma group, indicating it as a potential vector. The association of leafhoppers with their hosts may be used in deciding which management strategies to adopt against weeds and diseases in citrus orchards.

Wolbachia infection complexity among insects in the tropical rice-field community.

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Kittayapong, P; Jamnongluk, W; Thipaksorn, A; Milne, J R; Sindhusake, C

2003-04-01

Wolbachia are a group of intracellular bacteria that cause reproductive alterations in their arthropod hosts. Widely discordant host and Wolbachia phylogenies indicate that horizontal transmission of these bacteria among species sometimes occurs. A likely means of horizontal transfer is through the feeding relations of organisms within communities. Feeding interactions among insects within the rice-field insect community have been well documented in the past. Here, we present the results of a polymerase chain reaction-based survey and phylogenetic analysis of Wolbachia strains in the rice-field insect community of Thailand. Our field survey indicated that 49 of 209 (23.4%) rice-field insect species were infected with Wolbachia. Of the 49 infected species, 27 were members of two feeding complexes: (i) a group of 13 hoppers preyed on by 2 mirid species and parasitized by a fly species, and (ii) 2 lepidopteran pests parasitized by 9 wasp species. Wolbachia strains found in three hoppers, Recilia dorsalis, Nephotettix malayanus and Nisia nervosa, the two mirid predators, Cyrtorhinus lividipennis and Tytthus chinensis, and the fly parasitoid, Tomosvaryella subvirescens, were all in the same Wolbachia clade. In the second complex, the two lepidopteran pests, Cnaphalocrocis medinalis and Scirpophaga incertulas, were both infected with Wolbachia from the same clade, as was the parasitoid Tropobracon schoenobii. However, none of the other infected parasitoid species in this feeding complex was infected by Wolbachia from this clade. Mean (+/- SD) genetic distance of Wolbachia wsp sequences among interacting species pairs of the hopper feeding complex (0.118 +/- 0.091 nucleotide sequence differences), but not for the other two complexes, was significantly smaller than that between noninteracting species pairs (0.162 +/- 0.079 nucleotide sequence differences). Our results suggest that some feeding complexes, such as the hopper complex described here, could be an important

Feeding and defecation behavior of Triatoma rubida (Uhler, 1894) (Hemiptera: Reduviidae) under laboratory conditions, and its potential role as a vector of Chagas disease in Arizona, USA.

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Reisenman, Carolina E; Gregory, Teresa; Guerenstein, Pablo G; Hildebrand, John G

2011-10-01

Chagas disease is caused by the parasite Trypanosoma cruzi, which is transmitted to humans by blood-sucking triatomine insects. This disease is endemic throughout Mexico and Central and South America, but only a few autochthonous cases have been reported in the United States, despite the fact that infected insects readily invade houses and feed on humans. Competent vectors defecate during or shortly after feeding so that infective feces contact the host. We thus studied the feeding and defecation behaviors of the prevalent species in southern Arizona, Triatoma rubida. We found that whereas defecation during feeding was frequent in females (93%), it was very rare in immature stages (3%), and absent in males. Furthermore, more than half of the immature insects that exhibited multiple feeding bouts (62%) defecated during interruptions of feeding, i.e., while likely on or near the host. These results indicate that T. rubida potentially could transmit T. cruzi to humans.

Significance of the tropical fire ant Solenopsis geminata (hymenoptera: formicidae) as part of the natural enemy complex responsible for successful biological control of many tropical irrigated rice pests.

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Way, M J; Heong, K L

2009-10-01

The tropical fire ant Solenopsis geminata (Fabricius) often nests very abundantly in the earthen banks (bunds) around irrigated rice fields in the tropics. Where some farmers habitually drain fields to the mud for about 3-4 days, the ants can quickly spread up to about 20 m into the fields where they collect food, including pest prey such as the eggs and young of the apple snail Pomacea caniculata (Lamarck) and insects such as lepidopterous larvae and hoppers, notably Nilaparvata lugens (Stäl) the brown planthopper (Bph) and green leafhoppers Nephotettix spp. Even in drained fields, the activity of S. geminata is restricted by rainfall in the wet season. The relatively few ant workers that forage characteristically into drained fields and on to the transplanted clumps of rice plants (hills) kill the normally few immigrant Bph adults but are initially slower acting than other species of the natural enemy complex. However, larger populations of Bph are fiercely attacked and effectively controlled by rapidly recruited ant workers; whereas, in the absence of the ant, the other natural enemies are inadequate. In normal circumstances, there is no ant recruitment in response to initially small populations of immigrant Bph and no evidence of incompatibility between ant foragers and other natural enemies such as spiders. However, when many ants are quickly and aggressively recruited to attack large populations of Bph, they temporarily displace some spiders from infested hills. It is concluded that, in suitable weather conditions and even when insecticides kill natural enemies within the rice field, periodic drainage that enables S. geminata to join the predator complex is valuable for ant-based control of pests such as snails and Lepidoptera, and especially against relatively large populations of Bph. Drainage practices to benefit ants are fully compatible with recent research, which shows that periodic drainage combats problems of 'yield decline' in intensively irrigated

Phytoreovirus-like sequences isolated from salivary glands of the glassy-winged sharpshooter Homolodisca vitripennis (Hemiptera: Cicadellidae)

International Nuclear Information System (INIS)

Katsar, C.S.; Hunter, W.B.; Sinisterra, X.H.

2007-01-01

The salivary glands of the Glassy-winged sharpshooter (GWSS), Homalodisca vitripennis Germar 1821, (syn. H. coagulata, Hemiptera: Cicadellidae) were collected and used to produce a cDNA library. Examination by BLASTX analyses identified 2 viral sequences, one a 610-base pair fragment and a second 839-base pair fragment, both of which had significant homology to viruses within the genus Phytoreovirus. Resequencing of the fragments confirmed sequence validities. These sequences were used for in silico protein translation and BLASTP analysis confirming the established homology. While the GWSS is the primary vector of Pierce's disease of grapes, this is the first report that GWSS may be a vector of a phytoreoviruses. Phylogenetic and homology comparisons with BLASTX, BLASTP, and PAUP analyses indicated that the viral sequences isolated from GWSS were closely related to the viruses in the Family Reoviridae, Genus Phytoreovirus, specifically Rice Dwarf Phytoreovirus (RDV). RDV is the only plant reovirus that is not limited to the phloem. Phytoreoviruses are transmitted in a propagative manner by cicadellid leafhoppers (Hemiptera: Cicadellidae), which acquire and transmit them during feeding. Phytoreoviruses have been reported from Agallian, Agalliopsis, Nephotettix, and Recilia, genera of leafhoppers, with evidence for transovarial transmission. The GWSS, although considered to feed primarily from the xylem, ingests from other plant tissues, such as the phloem and mesophyll during probing similar to other leafhoppers. The feeding behavior and wide host range of the GWSS provides an overlapping condition for these two organisms, leafhopper and virus. GWSS will feed from grasses as a transitory host, and on herbaceous and woody plants as primary hosts, which may favor the acquisition and transmission of Phytoreovirus by this leafhopper. Monitoring for an increase of Phytoreovirus spread in graminaceous crops that are in proximity to vineyards or tree crop orchards, where

Mesoionic Pyrido[1,2-a]pyrimidinone Insecticides: From Discovery to Triflumezopyrim and Dicloromezotiaz.

Science.gov (United States)

Zhang, Wenming

2017-09-19

One of the greatest global challenges is to feed the ever-increasing world population. The agrochemical tools growers currently utilize are also under continuous pressure, due to a number of factors that contribute to the loss of existing products. Mesoionic pyrido[1,2-a]pyrimidinones are an unusual yet very intriguing class of compounds. Known for several decades, this class of compounds had not been systemically studied until we started our insecticide discovery program. This Account provides an overview of the efforts on mesoionic pyrido[1,2-a]pyridinone insecticide discovery, beginning from the initial high throughput screen (HTS) discovery to ultimate identification of triflumezopyrim (4, DuPont Pyraxalt) and dicloromezotiaz (5) for commercialization as novel insecticides. Mesoionic pyrido[1,2-a]pyrimidinones with a n-propyl group at the 1-position, such as compound 1, were initially isolated as undesired byproducts from reactions for a fungicide discovery program at DuPont Crop Protection. Such compounds showed interesting insecticidal activity in a follow-up screen and against an expanded insect species list. The area became an insecticide hit for exploration and then a lead area for optimization. At the lead optimization stage, variations at three regions of compound 1, i.e., side-chain (n-propyl group), substituents on the 3-phenyl group, and substitutions on the pyrido- moiety, were explored with many analogues prepared and evaluated. Breakthrough discoveries included replacing the n-propyl group with a 2,2,2-trifluoroethyl group to generate compound 2, and then with a 2-chlorothiazol-5-ylmethyl group to form compound 3. 3 possesses potent insecticidal activity not only against a group of hopper species, including corn planthopper (Peregrinus maidis (Ashmead), CPH) and potato leafhopper (Empoasca fabae (Harris), PLH), as well as two key rice hopper species, namely, brown planthopper (Nilaparvata lugens (Stål), BPH) and rice green leafhopper (Nephotettix

The cicadas of Argentina with new records, a new genus and fifteen new species (Hemiptera: Cicadoidea: Cicadidae).

Science.gov (United States)

Sanborn, Allen F; Heath, Maxine S

2014-10-11

within Guyalna bonaerensis (Berg, 1879). Derotettix proseni Torres, 1945 is determined to be a junior synonym of Derotettix wagneri Distant, 1905 syn. n. Dorisiana metcalfi nom. nov. pro Cicada viridis Olivier, 1790 nec Cicada viridis Linnaeus, 1758 is proposed. Tettigades lizeriana Delétang, 1919 is shown to be an invalid name for the purposes of zoological nomenclature. The first records for Argentina of Fidicinoides determinata (Walker, 1858), Fidicinoides vinula (Stål, 1854) comb. n., rev. stat., Prasinosoma fuembuenai Torres, 1963, Ariasa bilaqueata (Uhler, 1903), Ariasa colombiae (Distant, 1892), Carineta boliviana Distant, 1905, Carineta gemella Boulard, 1986, Calyria stigma (Walker, 1850), Selymbria pandora Distant, 1911, Taphura hastifera (Walker, 1858), Taphura misella (Stål, 1854), and Tettigades angularis Torres, 1958 are provided. Ten species are removed from the Argentine cicada fauna. The new records and new species represent a 36% increase in the known cicada fauna. Fifty-eight species (54%) and 10 genera (27%) are currently endemic to Argentina.