996 resultados para chelating agent


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The life history and host range of the lantana beetle, Alagoasa extrema, a potential biocontrol agent for Lantana spp. were investigated in a quarantine unit at the Alan Fletcher Research Station, Brisbane, Australia. Adults feed on leaves and females lay batches of about 17 eggs on the soil surface around the stems of plants. The eggs take 16 days to hatch and newly emerged larvae move up the stem to feed on young leaves. Larvae feed for about 23 days and there are three instars. There is a prepupal non-feeding stage that lasts about 12 days and the pupal stage, which occurs in a cocoon in the soil, lasts 16 days. Teneral adults remain in the cocoon for 3 days to harden prior to emergence. Males live for about 151 days while females live for about 127 days. The pre-oviposition period is 19 days. In no-choice larval feeding trials, nine plant species, representing three families, supported development to adult. Three species, Aloysia triphylla, Citharexylum spinosum and Pandorea pandorana were able to support at least two successive generations. These results confirm those reported in South Africa and suggest that A. extrema is not sufficiently specific for release in Australia. Furthermore, it is not recommended for release in any other country which is considering biological control of lantana.

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Parthenium (Parthenium hysterophorus L.), a major weed causing economic, environmental, and human and animal health problems in Australia and several countries in Asia, Africa, and the Pacific, has been a target for biological control in Australia since the mid-1970s. Nine species of insects and two rust fungi have been introduced as biological control agents into Australia. These include Carmenta sp. nr ithacae, a root feeding agent from Mexico. The larvae of C. sp. nr ithacae bore through the stem-base into the root where they feed on the cortical tissue of the taproot. During 1998-2002, 2,816 larval-infested plants and 387 adults were released at 31 sites across Queensland, Australia. Evidence of field establishment was first observed in two of the release sites in central Queensland in 2004. Annual surveys at these sites and nonrelease sites during 2006-2011 showed wide variations in the incidence and abundance of C. sp. nr ithacae between years and sites. Surveys at three of the nine release sites in northern Queensland and 16 of the 22 release sites in central Queensland confirmed the field establishment of C. sp. nr ithacae in four release sites and four nonrelease sites, all in central Queensland. No field establishment was evident in the inland region or in northern Queensland. A CLIMEX model based on the native range distribution of C. sp. nr ithacae predicts that areas east of the dividing range along the coast are more suitable for field establishment than inland areas. Future efforts to redistribute this agent should be restricted to areas identified as climatically favorable by the CLIMEX model.

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Among the various substituted coumarins investigated only 7-acetoxycoumarin is observed to photodimerize topochemically in the crystalline state and this observation may be of importance in the context of "crystal engineering".

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Cat's claw creeper, Dolichandra unguis-cati (L.) L.G. Lohman (syn: Macfadyena unguis-cati (L.) A.H. Gentry) (Bignoniaceae), a major environmental weed in Queensland and New South Wales, is a Weed of National Significance and an approved target for biological control. A leaf-mining jewel beetle, Hylaeogena jureceki Obenberger (Coleoptera: Buprestidae), first collected in 2002 from D. unguis-cati in Brazil and Argentina, was imported from South Africa into a quarantine facility in Brisbane in 2009 for host-specificity testing. H. jureceki adults chew holes in leaves and lay eggs on leaf margins and the emerging larvae mine within the leaves of D. unguis-cati. The generation time (egg to adult) of H. jureceki under quarantine conditions was 55.4 ± 0.2 days. Host-specificity trials conducted in Australia on 38 plant species from 11 families supplement and support South African studies which indicated that H. jureceki is highly host-specific and does not pose a risk to any non-target plant species in Australia. In no-choice tests, adults survived significantly longer (>32 weeks) on D. unguis-cati than on non-target test plant species (<3 weeks). Oviposition occurred on D. unguis-cati and one non-target test plant species, Citharexylum spinosum (Verbenaceae), but no larval development occurred on the latter species. In choice tests involving D. unguis-cati, C. spinosum and Avicennia marina (Avicenniaceae), feeding and oviposition were evident only on D. unguis-cati. The insect was approved for field release in Australia in May 2012.

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A leaf-feeding geometrid, Chiasmia assimilis (Warren), was introduced into northern Queensland from South Africa in 2002 as a biological control agent for the invasive woody weed, prickly acacia, Acacia nilotica subsp. indica (Bentham) Brenan. The insect established in infestations in coastal areas between the townships of Ayr and Bowen where the larvae periodically cause extensive defoliation at some localities during summer and autumn. The impact of this herbivory on a number of plant parameters, including shoot length, basal stem diameter, root length, number of leaves, number of branches, and above and below ground biomass was investigated at one coastal site through an insect exclusion trial using potted seedlings and regular spray applications of a systemic insecticide to exclude the biological control agent. Half the seedlings, both sprayed and unsprayed, were placed beneath the prickly acacia canopy, the other half were placed in full sunlight. Larvae of C. assimilis were found on unsprayed seedlings in both situations. The effects of herbivory, however, were significant only for seedlings grown beneath the canopy. At the end of the five-month trial period, shoot length of these seedlings was reduced by 30%, basal stem diameter by 44%, root length by 15%, number of leaves by 97%, above ground biomass by 87%, and below ground biomass by 77% when compared to sprayed seedlings. Implications are that the insect, where established, may reduce seedling growth beneath existing canopies and in turn may help limit the formation of dense infestations. Crown Copyright (C) 2012 Published by Elsevier Inc. All rights reserved.

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In a marketplace where millions of dollars are spent on the design of mobile games (m-games), social marketers are now using this technology as a tool for behaviour change. Despite high expenditure by governments and non-profits on social marketing m-games, little is known about their effectiveness in terms of creating value. Value creation has been demonstrated to have an important impact on satisfaction and behaviour. This paper reports the results of a qualitative study involving four focus groups with 23 participants to reveal two categories of experiential value, entertainment and behaviour. Additionally, it was discovered that entertainment could be characterised by amusement and social value dimensions. Whereas, behaviour could be made up of information, simulation and distraction value dimensions. The categories of value, as well as the dimensions of information, simulation and distraction are entirely new to the social marketing literature and thus represents a unique contribution to social marketing.

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Spring barley is the most important crop in Finland based on cultivated land area. Net blotch, a disease caused by Pyrenophora teres Drech., is the most damaging disease of barley in Finland. The pressure to improve the economics and efficiency of agriculture has increased the need for more efficient plant protection methods. Development of durable host-plant resistance to net blotch is a promising possibility. However, deployment of disease resistant crops could initiate selection pressure on the pathogen (P. teres) population. The aim of this study was to understand the population biology of P. teres and to estimate the evolutionary potential of P. teres under selective pressure following deployment of resistance genes and application of fungicides. The study included mainly Finnish P. teres isolates. Population samples from Russia and Australia were also included. Using AFLP markers substantial genotypic variation in P. teres populations was identified. Differences among isolates were least within Finnish fields and significantly higher in Krasnodar, Russia. Genetic differentiation was identified among populations from northern Europe and from Australia, and between the two forms P. teres f. teres (PTT, net form of net blotch) and P. teres f. maculata (PTM, spot form of net blotch) in Australia. Differentiation among populations was also identified based on virulence between Finnish and Russian populations, and based on prochloraz (fungicide) tolerance in the Häme region in Finland. Surprisingly only PTT was recovered from Finland and Russia although both forms were earlier equally common in Finland. The reason for the shift in occurrence of forms in Finland remained uncertain. Both forms were found within several fields in Australia. Sexual reproduction of P. teres was supported by recover of both mating types in equal ratio in those areas although the prevalence of sexual mating seems to be less in Finland than in Australia. Population from Krasnodar was an exception since only one mating type was found in there. Based on the substantial high genotypic variation in Krasnodar it was suggested go represent an old P. teres population, whereas the Australian samples were suggested to represent newer populations. In conclusion, P. teres populations are differentiated at several levels. Human assistance in dispersal of P. teres on infected barley seed is obvious and decreases the differentiation among populations. This can increase the plant protection problems caused by this pathogen. P. teres is capable of sexual reproduction in several areas but the prevalence varies. Based on these findings it is apparent that P. teres has the potential to pose more serious problems in barley cultivation if plant protection is neglected. Therefore, good agricultural practices, including crop rotation and the use of healthy seed, are recommended.

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The leaf-tying moth Hypocosmia pyrochroma Jones (Lepidoptera: Pyralidae), a native of sub tropical South America, has been introduced as a biological control agent for cat’s claw creeper, Dolichandra unguis-cati (L.) Lohman (Bignoniaceae), in Australia and South Africa. So far there has been no evidence of its field establishment in either country. A narrow temperature tolerance is a potential limiting factor for the establishment of weed biological control insects in novel habitats. In this study, we evaluated the effect of seven constant temperatures (12–40 °C) on the survival and development of H. pyrochroma in temperature-controlled cabinets. Temperatures between 20 and 30 °C were the most favorable for adult survival, oviposition, egg hatching, and larval and pupal development. Adult survival (12–40 °C) and egg development (15–35 °C) showed tolerance for wider temperature ranges than oviposition, and larval and pupal development, which were all negatively affected by both high (>30 °C) and low (<20 °C) temperatures. The degree-day (DD) requirement to complete a generation was estimated as 877 above a threshold temperature of 12 °C. Based on DD requirements and an obligatory winter diapause of pupae from mid-autumn to mid-spring, the potential number of generations (egg to adult) the leaf-tying moth can complete in a year in Australia or South Africa range from one to three. A climate-matching model predicted that the inland regions of both Australia and South Africa are less favorable for H. pyrochroma than the coastal areas. The study suggested that H. pyrochroma is more likely to establish in the coastal areas of Australia where most of the cat’s claw creeper infestations occur, than in South Africa where most of the cat’s claw creeper infestations are inland.

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The rust fungus Puccinia spegazzinii was introduced into Papua New Guinea (PNG) in 2008 as a classical biological control agent of the invasive weed Mikania micrantha (Asteraceae), following its earlier release in India, mainland China and Taiwan. Prior to implementing field releases in PNG, assessments were conducted to determine the most suitable rust pathotype for the country, potential for damage to non-target species, most efficient culturing method and potential impact to M. micrantha. The pathotype from eastern Ecuador was selected from the seven pathotypes tested, since all the plant populations evaluated from PNG were highly susceptible to it. None of the 11 plant species (representing eight families) tested to confirm host specificity showed symptoms of infection, supporting previous host range determination. A method of mass-producing inoculum of the rust fungus, using a simple technology which can be readily replicated in other countries, was developed. Comparative growth trials over one rust generation showed that M. micrantha plants infected with the rust generally had both lower growth rates and lower final dry weights, and produced fewer nodes than uninfected plants. There were significant correlations between the number of pustules and (a) the growth rate, (b) number of new nodes and (c) final total dry weight of single-stemmed plants placed in open sunlight and between the number of pustules and number of new nodes of multi-stemmed plants placed under cocoa trees. The trials suggest that field densities of M. micrantha could be reduced if the rust populations are sufficiently high. Crown Copyright (C) 2013 Published by Elsevier Inc. All rights reserved.

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Carpintero and Dellap, (Hemiptera: Thaumastocoridae) is a native Australian sap-feeding insect that has become invasive and seriously damaging to commercially grown in the Southern Hemisphere. Lin and Huber (Hymenoptera: Mymaridae) was recently discovered as an egg parasitoid of the Thaumastocoridae in Australia. Mitochondrial DNA (mtDNA; cytochrome oxidase subunit I, COI) sequence diversity amongst 104 individuals from these native populations revealed 24 sequence haplotypes. The COI haplotypes of individuals collected from the Sydney and Southeast Queensland clustered in distinct groups, indicating limited spread of the insect between the regions. Individuals collected from Perth in Western Australia were represented by four COI haplotypes. Although this population is geographically more isolated from other populations, two COI haplotypes were identical to haplotypes found in the Sydney region. The results suggest that has recently been introduced into Perth, possibly from the Sydney area. The high mtDNA diversity and limited spread that is suggested for is in contrast to the lack of geographic associated mtDNA diversity and extensive spread of . If implemented as a biological control agent, this factor will need to be considered in collecting and releasing .

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The leaf-tying moth Hypocosmia pyrochroma Jones (Lepidoptera: Pyralidae), a native of sub tropical South America, has been introduced as a biological control agent for cat’s claw creeper, Dolichandra unguis-cati (L.) Lohman (Bignoniaceae), in Australia and South Africa. So far there has been no evidence of its field establishment in either country. A narrow temperature tolerance is a potential limiting factor for the establishment of weed biological control insects in novel habitats. In this study, we evaluated the effect of seven constant temperatures (12–40 °C) on the survival and development of H. pyrochroma in temperature-controlled cabinets. Temperatures between 20 and 30 °C were the most favorable for adult survival, oviposition, egg hatching, and larval and pupal development. Adult survival (12–40 °C) and egg development (15–35 °C) showed tolerance for wider temperature ranges than oviposition, and larval and pupal development, which were all negatively affected by both high (>30 °C) and low (<20 °C) temperatures. The degree-day (DD) requirement to complete a generation was estimated as 877 above a threshold temperature of 12 °C. Based on DD requirements and an obligatory winter diapause of pupae from mid-autumn to mid-spring, the potential number of generations (egg to adult) the leaf-tying moth can complete in a year in Australia or South Africa range from one to three. A climate-matching model predicted that the inland regions of both Australia and South Africa are less favorable for H. pyrochroma than the coastal areas. The study suggested that H. pyrochroma is more likely to establish in the coastal areas of Australia where most of the cat’s claw creeper infestations occur, than in South Africa where most of the cat’s claw creeper infestations are inland.

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Babul scale Anomalococcus indicus Ramakrishna Ayyar, a major pest of Vachellia nilotica (L.f.) P.J.H. Hurter & Mabb. on the Indian subcontinent, has been identified as a potential biocontrol agent for prickly acacia V. nilotica subsp. indica (Benth.) Kyal. & Boatwr. in Australia and was imported from southern India for detailed assessment. The life history of A. indicus under controlled glasshouse conditions was determined as a part of this assessment. Consistent with other scale species, A. indicus has a distinct sexual dimorphism which becomes apparent during the second instar. Females have three instars, developing into sexually mature nymphs after 52 days. The generation time from egg to egg was 89 days. Females are ovoviviparous, ovipositing mature eggs into a cavity underneath their body. An average of 802 +/- 114 offspring were produced per female. Reproductive output was closely associated with female size; larger females produced more than 1200 offspring. Crawlers emerged from beneath the female after an indeterminate period of inactivity. They have the only life stage at which A. indicus can disperse, though the majority settle close to their parent female forming aggregative distributions. In the absence of food, most crawlers died within three days. Males took 62 days to develop through five instars. Unlike females, males underwent complete metamorphosis. Adult males were small and winged, and lived for less than a day. Parthenogenesis was not observed in females excluded from males. The life history of A. indicus allows it to complement other biological control agents already established on prickly acacia in Australia.

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In this study, we used Parthenium hysterophorus and one of its biological control agents, the winter rust (Puccinia abrupta var. partheniicola) as a model system to investigate how the weed may respond to infection under a climate change scenario involving an elevated atmospheric CO2 (550 μmol mol−1) concentration. Under such a scenario, P. hysterophorus plants grew significantly taller (52%) and produced more biomass (55%) than under the ambient atmospheric CO2 concentration (380 μmol mol−1). Following winter rust infection, biomass production was reduced by 17% under the ambient and by 30% under the elevated atmospheric CO2 concentration. The production of branches and leaf area was significantly increased by 62% and 120%, under the elevated as compared with ambient CO2 concentration, but unaffected by rust infection under either condition. The photosynthesis and water use efficiency (WUE) of P. hysterophorus plants were increased by 94% and 400%, under the elevated as compared with the ambient atmospheric CO2 concentration. However, in the rust-infected plants, the photosynthesis and WUE decreased by 18% and 28%, respectively, under the elevated CO2 and were unaffected by the ambient atmospheric CO2 concentration. The results suggest that although P. hysterophorus will benefit from a future climate involving an elevation of the atmospheric CO2 concentration, it is also likely that the winter rust will perform more effectively as a biological control agent under these same conditions.

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Aminopolykarboksyylaatteja, kuten etyleenidiamiinitetraetikkahappoa (EDTA), on käytetty useiden vuosikymmenien ajan erinomaisen metalli-ionien sitomiskyvyn vuoksi kelatointiaineena lukuisissa sovelluksissa sekä analytiikassa että monilla teollisisuuden aloilla. Näiden yhdisteiden biohajoamattomuus on kuitenkin herättänyt huolta viime aikoina, sillä niiden on havaittu olevan hyvin pysyviä luonnossa. Tämä työ on osa laajempaa tutkimushanketta, jossa on tavoitteena löytää korvaavia kelatointiaineita EDTA:lle. Tutkimuksen aiheena on kuuden kelatointiaineen metalli-ionien sitomiskyvyn kartoitus. EDTA:a paremmin luonnossa hajoavina nämä ovat ympäristöystävällisiä ehdokkaita korvaaviksi kelatointiaineiksi useisiin sovelluksiin. Työssä tutkittiin niiden kompleksinmuodostusta useiden metalli-ionien kanssa potentiometrisella titrauksella. Metalli-ionivalikoima vaihteli hieman kelatointiaineesta riippuen sisältäen magnesium-, kalsium-, mangaani-, rauta-, kupari-, sinkki-, kadmium-, elohopea-, lyijy- ja lantaani-ionit. Tutkittavat metallit oli valittu tähtäimessä olevien sovellusten, synteesissä ilmenneiden ongelmien tai ympäristönäkökohtien perusteella. Tulokset osoittavat näiden yhdisteiden metallinsitomiskyvyn olevan jonkin verran heikompi kuin EDTA:lla, mutta kuitenkin riittävän useisiin sovelluksiin kuten sellunvalkaisuprosessiin. Myrkyllisten raskasmetallien, kadmiumin, elohopen ja lyijyn kohdalla EDTA:a heikompi sitoutuminen on eduksikin, koska se yhdistettynä parempaan biohajoavuuteen saattaa alentaa tutkittujen yhdisteiden kykyä mobilisoida kyseisiä metalleja sedimenteistä. Useimmilla tutkituista yhdisteistä on ympäristönäkökulmasta etuna myös EDTA:a pienempi typpipitoisuus.