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Sarah M Swope - One of the best experts on this subject based on the ideXlab platform.
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native and invading yellow starthistle Centaurea solstitialis microbiomes differ in composition and diversity of bacteria
mSphere, 2019Co-Authors: Sarah M Swope, Patricia Luirving, Julia G Harencar, Hailey Sounart, Shana R Welles, David A Baltrus, Katrina M DlugoschAbstract:ABSTRACT Invasive species could benefit from being introduced to locations with more favorable species interactions, including the loss of enemies, the gain of mutualists, or the simplification of complex interaction networks. Microbiomes are an important source of species interactions with strong fitness effects on multicellular organisms, and these interactions are known to vary across regions. The highly invasive plant yellow starthistle (Centaurea solstitialis) has been shown to experience more favorable microbial interactions in its invasions of the Americas, but the microbiome that must contribute to this variation in interactions is unknown. We sequenced amplicons of 16S rRNA genes to characterize bacterial community compositions in the phyllosphere, ectorhizosphere, and endorhizosphere of yellow starthistle plants from seven invading populations in California, USA, and eight native populations in Europe. We tested for the differentiation of microbiomes by geography, plant compartment, and plant genotype. Bacterial communities differed significantly between native and invading plants within plant compartments, with consistently lower diversity in the microbiome of invading plants. The diversity of bacteria in roots was positively correlated with plant genotype diversity within both ranges, but this relationship did not explain microbiome differences between ranges. Our results reveal that these invading plants are experiencing either a simplified microbial environment or simplified microbial interactions as a result of the dominance of a few taxa within their microbiome. Our findings highlight several alternative hypotheses for the sources of variation that we observe in invader microbiomes and the potential for altered bacterial interactions to facilitate invasion success. IMPORTANCE Previous studies have found that introduced plants commonly experience more favorable microbial interactions in their non-native range, suggesting that changes to the microbiome could be an important contributor to invasion success. Little is known about microbiome variation across native and invading populations, however, and the potential sources of more favorable interactions are undescribed. Here, we report one of the first microbiome comparisons of plants from multiple native and invading populations, in the noxious weed yellow starthistle. We identify clear differences in composition and diversity of microbiome bacteria. Our findings raise new questions about the sources of these differences, and we outline the next generation of research that will be required to connect microbiome variation to its potential role in plant invasions.
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spatiotemporal variation in the strength of density dependence implications for biocontrol of Centaurea solstitialis
Biological Invasions, 2017Co-Authors: Sarah M Swope, William H Satterthwaite, Ingrid M ParkerAbstract:Invasive plants often occupy large ranges in the introduced region and consequently, local population dynamics vary in ways that affect the potential for biological control. We used matrix models to describe how density and population growth rate of Centaurea solstitialis varies in time and space. Matrix models were parameterized with data collected over 4 years from invasions at the coast, interior valleys and Sierra Nevada Mountains in California (USA). Asymptotic population growth rates (λ) varied dramatically across all populations and years (0.24–6.45), density varied by an order of magnitude and had a measurable effect on survival and λ in all populations. We used simulations to estimate the degree to which a biocontrol agent would need to reduce plant survival to control the weed. Because seedling survival was dependent on density, an agent that reduced seedling density had the effect of increasing the probability that the remaining plants survived to flowering. Interestingly, this meant that in the highest density populations the plant had the largest compensatory response to agent attack and experienced decline (λ ≤ 1.0) only after heavy losses (≥90%) to the agent. Conversely, in populations where density was so low that it had only a weak effect on survival, the agent was able to control the plant (λ ≤ 1.0) at much lower levels of attack (≤50%). In other words, the impact of a biocontrol agent is predicted to be lower where the plant reaches its highest densities because the surviving plants, now experiencing less intraspecific competition, are more likely to survive to flowering and produce more seeds. This may also be true for other invasive species in which strong density dependent processes are operating. For this reason, prospective agents ought to target density-independence vital rates.
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population genomic analyses reveal a history of range expansion and trait evolution across the native and invaded range of yellow starthistle Centaurea solstitialis
Molecular Ecology, 2017Co-Authors: Brittany S Barker, Sarah M Swope, Douglas G Luster, Krikor Andonian, Katrina M DlugoschAbstract:Identifying sources of genetic variation and reconstructing invasion routes for non-native introduced species is central to understanding the circumstances under which they may evolve increased invasiveness. In this study, we used genome-wide single nucleotide polymorphisms to study the colonization history of Centaurea solstitialis in its native range in Eurasia and invasions into the Americas. We leveraged this information to pinpoint key evolutionary shifts in plant size, a focal trait associated with invasiveness in this species. Our analyses revealed clear population genomic structure of potential source populations in Eurasia, including deep differentiation of a lineage found in the southern Apennine and Balkan Peninsulas and divergence among populations in Asia, eastern Europe, and western Europe. We found strongest support for an evolutionary scenario in which western European populations were derived from an ancient admixture event between populations from eastern Europe and Asia, and subsequently served as the main genetic ‘bridgehead’ for introductions to the Americas. Introductions to California appear to be from a single source region, and multiple, independent introductions of divergent genotypes likely occurred into the Pacific Northwest. Plant size has evolved significantly at three points during range expansion, including a large size increase in the lineage responsible for the aggressive invasion of California's interior. These results reveal a long history of colonization, admixture, and trait evolution in C. solstitialis, and suggest routes for improving evidence-based management decisions for one of the most ecologically and economically damaging invasive species in the western United States. This article is protected by copyright. All rights reserved.
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biocontrol attack increases pollen limitation under some circumstances in the invasive plant Centaurea solstitialis
Oecologia, 2014Co-Authors: Sarah M SwopeAbstract:Herbivore damage often deters pollinator visitation and many invasive plants in North America are pollinator-dependent. This has important implications for the biological control of invasive plants because it means that agents that deter pollinators may have a larger than expected impact on the plant. Yet interactions between pollinators and biocontrol agents are rarely evaluated. Centaurea solstitialis, one of the most problematic invasive species in California, is dependent on pollinators for reproduction. I factorially manipulated infection by a biocontrol pathogen and pollen supplementation to test for (1) pollen limitation in C. solstitialis, (2) whether infection increased pollen limitation, and (3) whether this varied across a soil moisture gradient. Plants growing on north-facing slopes where soil moisture was higher experienced mild pollen limitation in the absence of the pathogen and more pronounced pollen limitation when they were infected. Plants on drier south-facing slopes did not suffer from pollen limitation but instead appeared to suffer from resource limitation. Pathogen infection directly reduced seed set in C. solstitialis by 67–72 %. On north-facing slopes, infection had an additional, indirect effect by increasing the degree of pollen limitation plants experienced. The trait that mediates this indirect pathogen–pollinator interaction is the number of inflorescences plants produced: infected plants made fewer inflorescences which led to greater pollen limitation. Although in the present study this outcome is dependent on abiotic factors that vary over small spatial scales, exploiting other invasive plants’ dependence on pollinators by selecting agents that deter visitation may enhance agent impact.
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soil type mediates indirect interactions between Centaurea solstitialis and its biocontrol agents
Biological Invasions, 2012Co-Authors: Sarah M Swope, Ilana R SteinAbstract:Many invasive plants are attacked by more than one biocontrol agent. Attack by multiple enemies may give rise to indirect interactions, the nature of which may be influenced by the abiotic environment. We conducted a field experiment to determine (1) whether indirect interactions arose between Centaurea solstitialis, a foliar pathogen and three insect seed predators and (2) how the outcome was influenced by soil type (serpentine and non-serpentine). Because serpentine soils support high numbers of endemic species they are a priority for conservation. They also have very low calcium concentrations and Ca++ regulates plants’ ability to defend against pathogen infection. C. solstitialis growing on serpentine soil may therefore be more vulnerable to the pathogen and this may in turn affect the plant’s subsequent interactions with seed predators. We found that pathogen infection had a direct, negative impact on plant performance but its impact was not greater on serpentine plants. When attacked by the seed predators, inflorescences produced more viable seed when they were on plants infected with the pathogen than when they were on uninfected plants and the data suggest that this reflects reductions in larval seed-feeding. On the non-serpentine soil, the pathogen’s direct, negative impact was entirely canceled out by its indirect, positive effect via reduced seed predation. On the serpentine soil, plants attacked by the pathogen and the insect seed predators produced half as many seeds than plants attacked only by the seed predators. Our results demonstrate that biocontrol agent interactions may be modified by the plant and by the abiotic environment in a way that fundamentally alters their net impact on the weed.
Timothy L Widmer - One of the best experts on this subject based on the ideXlab platform.
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factors affecting infection of yellow starthistle Centaurea solstitialis by synchytrium solstitiale causal agent of false rust disease
Plant Disease, 2006Co-Authors: Timothy L Widmer, F GuermacheAbstract:Yellow starthistle (Centaurea solstitialis) is an annual invasive weed in the United States with Mediterranean origins. The expense of chemical control and the vast area of invasion make this weed an appropriate target for classical biological control. Observations of a field site in southern France revealed small orange galls on the leaves of yellow starthistle seedlings caused by the fungus Synchytrium solstitiale. Inoculation of yellow starthistle seedlings with a suspension of zoospores released from infected tissue resulted in infection. Ten days after inoculation, typical orange galls appeared on the exposed tissue. Preliminary host range testing showed up to 100% infection of C. solstitialis seedlings from both France and the United States and infection of Carthamus tinctorius, Centaurea americana, C. diffusa, C. rothrockii, C. squarrosa, and Helianthus annuus seedlings. No symptoms were observed on seedlings of Centaurea calcitrapa, C. maculosa, C. sulfurea, Cirsium californica, C. occidentale, Cynera cardunculus, and Taraxacum officinale. Zoospores were released in a pH range between 4.45 and 8.25 and optimally at temperatures between 5 and 15°C. Infection of yellow starthistle seedlings occurred after a minimum 1-h exposure to a zoospore suspension at 20°C.
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in vitro culturing of yellow starthistle Centaurea solstitialis for screening biological control agents
Biological Control, 2004Co-Authors: Karine Vidal, Fatiha Guermache, Timothy L WidmerAbstract:Abstract In an effort to design a bioassay to screen for biocontrol pathogens and their toxins, procedures were developed to produce calli of yellow starthistle (YST), Centaurea solstitialis (Asteraceae), on solid and liquid media. Three Murashige and Skoog (MS) media with different hormone additives were compared for their effects on the growth of the YST calli. The most effective medium was made of MS salts supplemented with two cytokinins and a low rate of auxin. The growth of the calli slowed when cytokinins were omitted. Similar results were observed in a bioassay setup to compare the reactions of the YST calli with those of detached leaves exposed to potential toxins in the culture filtrates of test fungi. After exposure for 96 h to different concentrations of culture filtrates from three Alternaria alternata isolates, the calli exposed to 100 and 50% concentrations of the filtrates were significantly more damaged than other concentrations tested, based on a visual rating scale. No differences were observed in the damage ratings among the A. alternata isolates tested. An additional bioassay was setup to determine if calli could be used to screen pathogenic fungi. After 48 h, a distinction could be made in a visual rating between calli treated with spores of a pathogen, Phoma exigua , and a nonpathogen, Penicillium sp., confirming that YST calli can be used to screen potential pathogenic fungi against YST.
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Molecular Identification of a New Member of the Clover Proliferation Phytoplasma Group (16SrVI) Associated with Centaurea solstitialis Virescence in Italy
European Journal of Plant Pathology, 2004Co-Authors: Francesco Faggioli, Timothy L Widmer, Graziella Pasquini, Valentina Lumia, Gaetano Campobasso, Paul C. QuimbyAbstract:In the United States, yellow starthistle ( Centaurea solstitialis ) is an annual invasive weed with Mediterranean origins. Malformed plants displaying witches' broom, fasciations, abortion of buds and flower virescence symptoms were observed in central Italy. Attempts to transmit the causal agent from the natural yellow starthistle host to periwinkle by grafting, resulted in typical symptoms of a phytoplasma, i.e. yellowing and shortening of internodes. The detection of phytoplasmas was obtained from both symptomatic yellow starthistle and periwinkle by the specific amplification of their 16S-23S rRNA genes. PCR amplification of extracted DNA from symptomatic plant samples gave a product of expected size. Asymptomatic plants did not give positive results. An amplicon obtained by direct PCR with universal primers P1/P7 was cloned and sequenced. The homology search using CLUSTALW program showed more than 99% similarity with Illinois elm yellows (ILEY) phytoplasma from Illinois (United States) and 97% with Brinjal little leaf (BLL) phytoplasma from India. Digestion of the nested-PCR products with restriction enzymes led to restriction fragment length polymorphism patterns referable to those described for phytoplasmas belonging to the clover proliferation (16S-VI) group. Since this is a previously undescribed disease, the name Centaurea solstitialis virescence has been tentatively assigned to it. This is a new phytoplasma with closest relationships to ILEY and BLL, but distinguishable from them on the basis of 16S rDNA homology, the different associated plant hosts and their geographical origin.
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synchytrium solstitiale sp nov causing a false rust on Centaurea solstitialis in france
Mycologia, 2004Co-Authors: Timothy L WidmerAbstract:A new species of Synchytrium, S. solstitiale, infecting leaves of Centaurea solstitialis in France, is described and illustrated. Synchytrium solstitiale caus- es development of orange to red galls on the leaves and petioles of living plants. It differs microscopically from all previously described species of the genus mainly in having larger sporangia and zoospores and resting spores that are formed in succession without an evanescent prosoral stage.
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first report of phoma exigua on Centaurea solstitialis asteraceae in russia
Plant Disease, 2002Co-Authors: Timothy L Widmer, Lisa A Castlebury, Amy Y RossmanAbstract:Phoma exigua Desm. (teleomorph Didymella exigua (Niessl) Sacc.) was isolated from wilted Centaurea solstitialis L. (yellow starthistle) plants displaying necrosis of the crown that were found near Krasnodar, Russia. The fungus was identified using morphological and cultural characteristics (1,2) and confirmed by sequencing the complete internal transcribed spacer region of the nuclear rDNA (GenBank Accession No. AY089978). P. exigua is a relatively common soilborne fungus that is weakly pathogenic on a diverse range of primarily dicotyledonous plants throughout the world (1). To our knowledge, it has never been reported previously on members of the genus Centaurea. Yellow starthistle is native to eastern Europe and the Mediterranean Region, and is now a noxious weed in North America for which P. exigua is being investigated as a potential biological control agent. Repeated pathogenicity studies (N = 30) resulted in a mortality of 80 and 93% within 7 days when 1-week-old seedlings were transplanted in soil...
Ingrid M Parker - One of the best experts on this subject based on the ideXlab platform.
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spatiotemporal variation in the strength of density dependence implications for biocontrol of Centaurea solstitialis
Biological Invasions, 2017Co-Authors: Sarah M Swope, William H Satterthwaite, Ingrid M ParkerAbstract:Invasive plants often occupy large ranges in the introduced region and consequently, local population dynamics vary in ways that affect the potential for biological control. We used matrix models to describe how density and population growth rate of Centaurea solstitialis varies in time and space. Matrix models were parameterized with data collected over 4 years from invasions at the coast, interior valleys and Sierra Nevada Mountains in California (USA). Asymptotic population growth rates (λ) varied dramatically across all populations and years (0.24–6.45), density varied by an order of magnitude and had a measurable effect on survival and λ in all populations. We used simulations to estimate the degree to which a biocontrol agent would need to reduce plant survival to control the weed. Because seedling survival was dependent on density, an agent that reduced seedling density had the effect of increasing the probability that the remaining plants survived to flowering. Interestingly, this meant that in the highest density populations the plant had the largest compensatory response to agent attack and experienced decline (λ ≤ 1.0) only after heavy losses (≥90%) to the agent. Conversely, in populations where density was so low that it had only a weak effect on survival, the agent was able to control the plant (λ ≤ 1.0) at much lower levels of attack (≤50%). In other words, the impact of a biocontrol agent is predicted to be lower where the plant reaches its highest densities because the surviving plants, now experiencing less intraspecific competition, are more likely to survive to flowering and produce more seeds. This may also be true for other invasive species in which strong density dependent processes are operating. For this reason, prospective agents ought to target density-independence vital rates.
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trait mediated interactions and lifetime fitness of the invasive plant Centaurea solstitialis
Ecology, 2010Co-Authors: Sarah M Swope, Ingrid M ParkerAbstract:Plants interact with numerous enemies and mutualists simultaneously and sequentially. Such multispecies interactions can give rise to trait-mediated indirect effects that are likely to be common in nature but which are also inherently difficult to predict. Understanding multispecies interactions is also important in the use of biological control agents to control invasive plants because modern approaches to biocontrol rely on releasing multiple agents for each target weed. Centaurea solstitialis is one of the most problematic invasive weeds in California, USA, and the weevil Eustenopus villosus is its dominant biological control agent. We conducted a field experiment to quantitatively assess the direct effect of the recently approved biocontrol pathogen Puccinia jaceae f.s. solstitialis on plant performance and any indirect effects that might arise by altering the plant's interactions with Eustenopus or its pollinators (principally the nonnative Apis mellifera). We documented both synergy and interference...
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Trait‐mediated interactions and lifetime fitness of the invasive plant Centaurea solstitialis
Ecology, 2010Co-Authors: Sarah M Swope, Ingrid M ParkerAbstract:Plants interact with numerous enemies and mutualists simultaneously and sequentially. Such multispecies interactions can give rise to trait-mediated indirect effects that are likely to be common in nature but which are also inherently difficult to predict. Understanding multispecies interactions is also important in the use of biological control agents to control invasive plants because modern approaches to biocontrol rely on releasing multiple agents for each target weed. Centaurea solstitialis is one of the most problematic invasive weeds in California, USA, and the weevil Eustenopus villosus is its dominant biological control agent. We conducted a field experiment to quantitatively assess the direct effect of the recently approved biocontrol pathogen Puccinia jaceae f.s. solstitialis on plant performance and any indirect effects that might arise by altering the plant's interactions with Eustenopus or its pollinators (principally the nonnative Apis mellifera). We documented both synergy and interference...
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widespread seed limitation affects plant density but not population trajectory in the invasive plant Centaurea solstitialis
Oecologia, 2010Co-Authors: Sarah M Swope, Ingrid M ParkerAbstract:In some plant populations, the availability of seeds strongly regulates recruitment. However, a scarcity of germination microsites, granivory or density-dependent mortality can reduce the number of plants that germinate or survive to flower. The relative strengths of these controls are unknown for most plant populations and for exotic invaders in particular. We conducted a seed addition experiment with a granivore exclusion treatment in a field setting to explore how these factors interact to regulate populations of the widespread invader Centaurea solstitialis (yellow starthistle) at three study sites across the plant’s range in California. We coupled the experimental approach with observational studies within established C. solstitialis populations to estimate seed rain, recruitment and mortality at natural densities. Seed limitation occurred in both experimental and observational plots in all populations. Although vertebrate granivores were active at each site, they had no effect on C. solstitialis recruitment. Density increased mortality, but the effect was variable and weak relative to its effect on fecundity. The seed limitation that was evident at the seedling stage persisted to flowering. Seed-limited populations such as these ought to be highly sensitive to losses to seed predators, and many biological control agents, including those established for C. solstitialis, are seed predators. However, flowering plant density was decoupled from seed production by a strong compensatory response in the surviving plants; seed production was nearly constant in plots across all seed addition levels. Thus, flowering plant density is reduced by the established biocontrol agents, but seed production compensates to replace the population every generation, and no long-term decline is predicted.
Christopher B Field - One of the best experts on this subject based on the ideXlab platform.
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In-field yellow starthistle (Centaurea solstitialis) volatile composition under elevated temperature and CO_2 and implications for future control
Chemoecology, 2015Co-Authors: Marina Oster, John J. Beck, Robert E. Furrow, Kara Yeung, Christopher B FieldAbstract:Abiotic stressors may affect biogenic volatile organic compounds (BVOCs) involved in plant communication. We examined how certain environmental conditions affect plant signaling via BVOC emission. Specifically, we investigated the effects of elevated CO_2 and temperature in situ on BVOCs produced by mechanically damaged leaves of Centaurea solstitialis L. (yellow starthistle), a major invasive weed in western North America, grown in grassland plots in the foothills of northern California. The headspace BVOCs of C. solstitialis were collected in situ by a customized Teflon^® bag and solid-phase microextraction and analyzed by gas chromatography–mass spectroscopy. Damaging leaves led to the release of 14 volatile compounds, predominantly sesquiterpenes. The co-occurrence of five compound pairs was highly significant across all treatments, which may be explained through synthesis by the same enzyme. We found no significant effect of treatment on the levels of individual or total volatiles. The stability of volatile profile for this invasive under future conditions should therefore (1) not alter indirect defense signaling and (2) support the selection of biological controls on the basis of their specificity to the identified in-field host plant BVOCs.
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in field yellow starthistle Centaurea solstitialis volatile composition under elevated temperature and co2 and implications for future control
Chemoecology, 2015Co-Authors: John J. Beck, Marina Oster, Robert E. Furrow, Kara Yeung, Christopher B FieldAbstract:Abiotic stressors may affect biogenic volatile organic compounds (BVOCs) involved in plant communication. We examined how certain environmental conditions affect plant signaling via BVOC emission. Specifically, we investigated the effects of elevated CO2 and temperature in situ on BVOCs produced by mechanically damaged leaves of Centaurea solstitialis L. (yellow starthistle), a major invasive weed in western North America, grown in grassland plots in the foothills of northern California. The headspace BVOCs of C. solstitialis were collected in situ by a customized Teflon® bag and solid-phase microextraction and analyzed by gas chromatography–mass spectroscopy. Damaging leaves led to the release of 14 volatile compounds, predominantly sesquiterpenes. The co-occurrence of five compound pairs was highly significant across all treatments, which may be explained through synthesis by the same enzyme. We found no significant effect of treatment on the levels of individual or total volatiles. The stability of volatile profile for this invasive under future conditions should therefore (1) not alter indirect defense signaling and (2) support the selection of biological controls on the basis of their specificity to the identified in-field host plant BVOCs.
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strong response of an invasive plant species Centaurea solstitialis l to global environmental changes
Ecological Applications, 2011Co-Authors: Jeffrey S Dukes, Nona R Chiariello, Scott R Loarie, Christopher B FieldAbstract:Global environmental changes are altering interactions among plant species, sometimes favoring invasive species. Here, we examine how a suite of five environmental factors, singly and in combination, can affect the success of a highly invasive plant. We introduced Centaurea solstitialis L. (yellow starthistle), which is considered by many to be California's most troublesome wildland weed, to grassland plots in the San Francisco Bay Area. These plots experienced ambient or elevated levels of warming, atmospheric CO2, precipitation, and nitrate deposition, and an accidental fire in the previous year created an additional treatment. Centaurea grew more than six times larger in response to elevated CO2, and, outside of the burned area, grew more than three times larger in response to nitrate deposition. In contrast, resident plants in the community responded less strongly (or did not respond) to these treatments. Interactive effects among treatments were rarely significant. Results from a parallel mesocosm experiment, while less dramatic, supported the pattern of results observed in the field. Taken together, our results suggest that ongoing environmental changes may dramatically increase Centaurea's prevalence in western North America.
Lincoln Smith - One of the best experts on this subject based on the ideXlab platform.
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assessing the biological control of yellow starthistle Centaurea solstitialis l prospective analysis of the impact of the rosette weevil ceratapion basicorne illiger
Agricultural and Forest Entomology, 2017Co-Authors: A P Gutierrez, Lincoln Smith, Massimo Cristofaro, Luigi Ponti, Michael J PitcairnAbstract:Yellow starthistle (Centaurea solstitialis L) (YST) is an invasive weed native to the Mediterranean region with a geographical centre of diversity in Turkey. It is widely established in Chile, Australia, and western North America. It arrived in California as a contaminant in alfalfa seed in 1859 and, by 2002, had infested >7.7 million hectares in the U.S.A. Biological control of YST using capitula feeding weevils, picture wing flies and a foliar rust pathogen has been ongoing in the western U.S.A. for more than three decades with limited success. Modelling and field research suggest natural enemies that kill whole plants and/or reduce seed production of survivors are good candidates for successful biological control. A candidate species with some of these attributes is the rosette weevil Ceratapion basicorne (Illiger). In the present study, a model of the rosette weevil is added to an extant system model of YST and its capitula feeding natural enemies and, in a GIS context, is used to assess YST control in the Palearctic region and the weevil's potential impact on YST in western U.S.A. The results obtained suggest densities of mature YST plants in western U.S.A. would be reduced by 70–80% in many areas.
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the effects of seed feeding insects on seed production of yellow starthistle Centaurea solstitialis l in adana province in southern turkey
Türkiye Biyolojik Mücadele Dergisi, 2016Co-Authors: Sibel Uygur, Lincoln Smith, Nezihi F UygurAbstract:Sari Peygamber Dikeni (Centaurea solstitialis L., Asteraceae), Turkiye’nin de icerisinde bulundugu Avrasya’ya ozgun bir bitki olup, Amerika Birlesik Devletlerinin batisinda da istilaci bir yabanci ottur. Bu bitki Amerika Birlesik Devletleri’nde kapitula (cicek basciklari) bocekleri ile biyolojik mucadelede hedef yabanci ot olup, Turkiye’deki boceklerin durumlari hakkinda cok az sey bilinmektedir. Bu calismada iki yil boyunca Turkiye’nin guneyindeki Adana ilinin uc farkli bolgesini temsil eden yedi ornekleme noktasindan kapitulalar (cicek basciklari) toplanmistir. Bulasik olmayan her bir kapituladaki ortalama saglikli tohum sayisi, kapitula capi ile iliskili olup, 10 ile 56 arasinda degismektedir. Genel olarak, bocek bulasikligi, kapituladaki saglikli tohum sayisi azaltmaktadir. Bulasik olmayan bir kapituladaki saglikli ortalama tohum sayisi 34,7 iken bulasik bir kapituladaki ortalama saglikli tohum sayisi 16,8 olup, % 52’lik azalma soz konusudur. Ancak azalis ayni zamanda kapitula buyuklugune de baglidir. Kapitulalar bocekler tarafindan % 5-55 oraninda bulasmaktadir. Bu oran Kaliforniya’da uzun zamandir gozlenen uc bolgenin degerleri ile kiyaslandiginda daha azdir (% 49 ila 89 arasi). Calisma alanlarinda parazitoidler % 25 oraninda gal olusturan bocekleri, % 4 oraninda gal olusturmayan bocekleri tercih etmekte iken Kaliforniya’da hemen hemen parazitizm yoktur. En yaygin bocekler tanilanmamis bir mordellid ve iki adet gal olusturan turdur. Bu iki tur; Urophora sirunaseva (Hering) (Diptera: Tephritidae) ve Isocolus scabiosae (Giraud) (Hymnenoptera: Cynipidae)’dir. Diger tohum bocekleri daha az yaygin olan Oxycarenus pallens (Herrich-Schaffer) (Hemiptera: Oxycarenidae), Bangasternus orientalis (Capiomont), Eustenopus villosus (Boheman) (Coleoptera: Curculionidae), ve Terellia uncinata White (Diptera: Tephritidae)’ dir. Yogun olarak bulunan herbivorlarin bazilari, Amerika Birlesik Devletlerinde olasi dogal dusman olarak degerlendirilebilecegi gibi, Turkiye’de de kitle uretimi yontemi veya koruma yontemi kullanilarak Sari Peygamber Dikeninin biyolojik mucadelesinde dusunulebilir
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In situ volatile collection, analysis, and comparison of three Centaurea species and their relationship to biocontrol with herbivorous insects.
Journal of Agricultural and Food Chemistry, 2008Co-Authors: John J. Beck, Lincoln Smith, Glory B MerrillAbstract:Centaurea solstitialis, commonly known as yellow starthistle, is an invasive plant listed as a noxious weed in the western areas of North America and is the target of classical biological control, which involves release of herbivores known to be specific to this plant. These insects often choose their host plant on the basis of the volatile organic compounds (VOCs) emitted. Accordingly, volatile analysis of host plants can provide insight into VOCs that may attract and/or repel the insect. To this end, solid-phase microextraction (SPME) and a customized collection bag were utilized to perform in situ volatile collection on intact and mechanically damaged leaves of Centaurea solstitialis, Centaurea cyanus, and Centaurea cineraria. Volatile identification was performed by GC-MS, and the VOC differences were determined. The plants C. solstitialis and C. cyanus have been reported to attract the weevil, Ceratapion basicorne, a candidate for biological control, whereas C. cineraria does not attract the weevil. ...
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A lace bug as biological control agent of yellow starthistle, Centaurea solstitialis L. (Asteraceae): an unusual choice.
Proceedings of the XII International Symposium on Biological Control of Weeds La Grande Motte France 22-27 April 2007, 2008Co-Authors: A. Paolini, Felea Cristina, Carlo Tronci, F. Lecce, Rustem Hayat, Massimo Cristofaro, Lincoln SmithAbstract:1 Biotechnology and Biological Control Agency, Via del Bosco 10, 00060 Sacrofano, Rome, Italy. 2 Ataturk University, Faculty of Agriculture, Plant Protection Department, 25240 TR Erzurum, Turkey. 3 ENEA C.R. Casaccia BIOTEC, Via Anguillarese 301, 00123 S. Maria di Galeria, Rome, Italy. 4 USDA-ARS, 800 Buchanan Street, Albany, CA 94710, USA. Corresponding author: A. Paolini . © CAB International 2008 A lace bug as biological control agent of yellow starthistle, Centaurea solstitialis L. (Asteraceae): an unusual choice
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broad nosed weevils feeding on Centaurea solstitialis in turkey with a description of the new species araxia cristofaroi sp n coleoptera curculionidae entiminae
Annals of The Entomological Society of America, 2008Co-Authors: L Gultekin, Massimo Cristofaro, R Borovec, Lincoln SmithAbstract:During exploration for new biological control agents of yellow starthistle, Centaurea solstitialis L. (Asteraceae: Cardueae), in eastern Turkey, we observed four species of broad-nosed weevils (subfamily Entiminae) that are newly associated with this plant: Epiphanops persicus (Chevrolat), Eusomomorphus oligops Daniel, Altonomus modestus (Khnzorian), and Araxia cristofaroi sp. n. Host plants of these species are recorded for the first time. Adults of E. persicus feed on young spines of C. solstitialis capitula (flower heads), whereas A. modestus and A. cristofaroi feed on leaves of C. solstitialis rosettes. Large numbers of E. oligops adults were observed feeding on leaves of both C. solstitialis and Russian knapweed, Acroptilon repens (L.). The genus Araxia Khnzorian is transferred from tribe Brachyderini Schoenherr to the tribe Sciaphilini Sharp, and it is redescribed. Female genitalia of this genus were studied and described for the first time. The new species, Araxia cristofaroi sp. n., is described, illustrated, and compared with the only other known Araxia species: A. mucronata Khnzorian. A taxonomic key discriminating the two Araxia species was developed. The new species differs by having claws that are almost equal in length, thinner and longer protibiae, wider antennal scape, more slender rostrum, and shorter body length. A. mucronata is newly recorded for Turkish fauna.