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Galls
Kinds of Galls Terms modified by Galls Selected AbstractsStrain E26 of Agrobacterium vitis, a Biological Control Agent of Grapevine Crown Gall, Does Not Contain virA and virG Pathogenic DeterminantsJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2009Qing Wei Abstract Risk assessment of biological control agents (BCAs) for the control of plant diseases in the field and/or laboratories has now become a necessary procedure before developing and producing novel BCAs. Agrobacterium vitis strain E26 is a promising potential biocontrol agent of grapevine crown gall disease. However, much less is understood about its safety or environmental risks. In this study, polymerase chain reaction (PCR) and Southern blot analyses were used to determine whether five essential virulence genes (virA, virG, iaaH, iaaM and ipt) were present in strain E26. Primers and probes were designed based on the conserved regions of each gene. The overall results obtained indicated that A. vitis strain E26 does not contain the virA and virG determinants, suggesting that this strain would be unlikely to elicit crown gall symptoms in either host or non-host plants. It seems that the iaaH, iaaM, or ipt gene were not present in strain E26 either. An applicable new approach combining PCR and Southern blot analyses to examine the pathogenicity of potential BCAs, particularly BCAs from the genus of Agrobacterium spp. was described. [source] Post-gall induction performance of Adelges Abietis (L.) (Homoptera: Adelgidae) is influenced by clone, shoot length, and density of colonising gallicolaeECOLOGICAL ENTOMOLOGY, Issue 1 2010LEAH FLAHERTY 1. We evaluated the effect of clone (one susceptible and one resistant clone), shoot length, crown level, and gallicola density on post-gall induction performance of Adelges abietis. Galls that had been successfully induced by one fundatrix on a range of shoot sizes were selected, and the number of gallicolae that could colonise the gall was manipulated. 2. Post-induction gall development success was inversely related to shoot length and was higher on the susceptible clone than on the resistant clone. As gallicola density did not influence the proportion of galls that successfully completed development, reduced post-induction gall development on large shoots was not likely to be result of an insufficient stimulus from gallicolae. 3. Clone was the only factor that significantly influenced gall volume and galls were larger on the susceptible clone than on the resistant clone. As gall volume did not increase when more gallicolae attempted to colonise a gall, competition within a gall increased. Gallicola survival was inversely related to the number of colonising gallicolae. Our results suggest that gall size may be limiting at natural densities. 4. Previous studies report positive relationships between gall induction success and fundatrix density, and between gall size and fundatrix density. As each fundatrix produces one egg mass of gallicolae, this study suggests that there may be a trade-off between the successful induction of a large gall and subsequent survival of gallicolae. 5. In the present study, clone influenced all measures of post-gall induction performance. Performance was always higher on the susceptible than on the resistant clone. [source] Structure and vertical stratification of plant galler,parasitoid food webs in two tropical forestsECOLOGICAL ENTOMOLOGY, Issue 3 2009MIGUEL R. PANIAGUA Abstract 1.,Networks of feeding interactions among insect herbivores and natural enemies such as parasitoids, describe the structure of these assemblages and may be critically linked to their dynamics and stability. The present paper describes the first quantitative study of parasitoids associated with gall-inducing insect assemblages in the tropics, and the first investigation of vertical stratification in quantitative food web structure. 2.,Galls and associated parasitoids were sampled in the understorey and canopy of Parque Natural Metropolitano in the Pacific forest, and in the understorey of San Lorenzo Protected Area in the Caribbean forest of Panama. Quantitative host,parasitoid food webs were constructed for each assemblage, including 34 gall maker species, 28 host plants, and 57 parasitoid species. 3.,Species richness was higher in the understorey for parasitoids, but higher in the canopy for gall makers. There was an almost complete turnover in gall maker and parasitoid assemblage composition between strata, and the few parasitoid species shared between strata were associated with the same host species. 4.,Most parasitoid species were host specific, and the few polyphagous parasitoid species were restricted to the understorey. 5.,These results suggest that, in contrast to better-studied leaf miner,parasitoid assemblages, the influence of apparent competition mediated by shared parasitoids as a structuring factor is likely to be minimal in the understorey and practically absent in the canopy, increasing the potential for coexistence of parasitoid species. 6.,High parasitoid beta diversity and high host specificity, particularly in the poorly studied canopy, indicate that tropical forests may be even more species rich in hymenopteran parasitoids than previously suspected. [source] Non-random distribution among a guild of parasitoids: implications for community structure and host survivalECOLOGICAL ENTOMOLOGY, Issue 6 2006ANTHONY M. ROSSI Abstract 1.,Immature stages of the gall midge, Asphondylia borrichiae, are attacked by four species of parasitoids, which vary in size and relative abundance within patches of the gall midge's primary host plant, sea oxeye daisy (Borrichia frutescens). 2.,In the current study, a bagging experiment found that the smallest wasp, Galeopsomyia haemon, was most abundant in galls exposed to natural enemies early in the experiment, when gall diameter is smallest, while the wasp with the longest ovipositor, Torymus umbilicatus, dominated the parasitoid community in galls that were not exposed until the 5th and 6th weeks when gall diameter is maximal. 3.,Moreover, the mean number of parasitoids captured using large artificial galls were 70% and 150% higher compared with medium and small galls respectively, while stem height of artificial galls significantly affected parasitoid distribution. Galls that were level with the top of the sea oxeye canopy captured 60% more parasitoids compared with those below the canopy and 50% more than galls higher than the plant canopy. 4.,These non-random patterns were driven primarily by the differential distribution of the largest parasitoid, T. umbilicatus, which was found significantly more often than expected on large galls and the smallest parasitoid of the guild, G. haemon, which tended to be more common on stems level with the top of the plant canopy. 5.,Large Asphondylia galls, especially those located near the top of the Borrichia canopy, were more likely to be discovered by searching parasitoids. Results using artificial galls were consistent with rates of parasitism of Asphondylia galls in native patches of sea oxeye daisy. Gall diameter was 19% greater and the rate of parasitism was reduced by almost 50% on short stems; as a result, gall abundance was 24% higher on short stems compared with ones located near the top of the plant canopy. 6.,These results suggest that parasitoid community composition within galls is regulated by both interspecific differences in ovipositor length and preferences for specific gall size and/or stem length classes. [source] Tritrophic interactions and trade-offs in herbivore fecundity on hybridising host plantsECOLOGICAL ENTOMOLOGY, Issue 3 2004Maria V. Cattell Abstract., 1. Interspecific plant hybridisation can have important evolutionary consequences for hybridising plants and for the organisms that they interact with on multiple trophic levels. In this study the effects of plant hybridisation on the abundance of herbivores and on the levels of herbivore parasitism were investigated. 2. Borrichia frutescens, B. arborescens, and their hybrid (B. × cubana) were censused for Asphondylia borrichiae galls and Pissonotus quadripustulatus plant hoppers in the Florida Keys. Levels of egg parasitism were determined by dissecting parental and hybrid stems and galls for herbivore and parasite eggs and larvae. Stem toughness and gall size are plant-mediated modes of protection from parasitism and these were also measured. For gall midges, fly size was measured as an estimate of fecundity. 3. Field censuses indicated that herbivore abundances varied on hybrid hosts relative to parent plant species and that the different herbivore species exhibited different patterns of abundance. Asphondylia borrichiae gall numbers followed the additive pattern of abundance while P. quadripustulatus numbers most closely resembled the dominance pattern. 4. Parasitism of P. quadripustulatus eggs was high on B. frutescens and the hybrids, and low on B. arborescens, which also had significantly tougher stems. Asphondylia borrichiae suffered the highest levels of parasitism on B. frutescens, the host plant which produced the smallest galls. On B. arborescens, which produced the largest galls, levels of A. borrichiae parasitism were lowest. Both parasitism and gall size were intermediate on the hybrid plants. Galls on B. arborescens and hybrid plants produced significantly smaller flies then those from B. frutescens suggesting that, when selecting hosts from among parent species and hybrids, gall flies may face a trade-off between escape from natural enemies and maximising fecundity. [source] Cecidophagy in adults of Demotina fasciculata (Coleoptera: Chrysomelidae) and its effect on the survival of Andricus moriokae (Hymenoptera: Cynipidae) inhabiting leaf galls on Quercus serrata (Fagaceae)ENTOMOLOGICAL SCIENCE, Issue 1 2010Takayoshi KATSUDA Abstract Females of Demotina fasciculata (Coleoptera: Chrysomelidae) were found to prefer to feed on galls induced by Andricus moriokae (Hymenoptera: Cynipidae) rather than on leaves of its host plant, Quercus serrata (Fagaceae). This is the first record of cecidophagy by adult chrysomelid beetles. Demotina fasciculata did not infest healthy galls induced by another unidentified cynipid species on the same host trees, but did feed on galls inhabited by an inquiline species Synergus quercicola (Hymenoptera: Cynipidae), presumably because such galls remained on the host trees longer than healthy galls. Galls of A. moriokae were infested more severely than cynipid galls inhabited by the inquiline. Therefore, higher density and thicker gall wall in A. moriokae galls seem to make them more suitable targets for D. fasciculata to attack. Larval chambers of A. moriokae galls were stripped by the infestation of gall walls and readily dropped to the ground, resulting in 100% death of cynipid larvae due to desiccation, while 62.5% of pupae survived when they had developed to the late stadium before the fall of larval chambers. [source] Detection of an invasive gall-inducing pest, Quadrastichus erythrinae (Hymenoptera: Eulophidae), causing damage to Erythrina variegata L. (Fabaceae) in Okinawa Prefecture, JapanENTOMOLOGICAL SCIENCE, Issue 2 2007Nami UECHI Abstract In 2005, Quadrastichus erythrinae Kim, 2004 (Hymenoptera: Eulophidae), which induces stem, petiole, and leaf galls on Erythrina variegata L. (Fabaceae), was found on the following six islands in Okinawa Prefecture, Japan: Okinawa, Kume, Miyako, Ishigaki, Iriomote, and Hateruma. Galls were also found in Vietnam. In Japan, no further infestation records have been reported from any of Japan's other south-western prefectures where Erythrina species grow. Because no Erythrina galls were observed in Okinawa Prefecture before 2005, Q. erythrinae seems to have invaded quite recently. [source] GEOGRAPHIC VARIATION IN THE EVOLUTION AND COEVOLUTION OF A TRITROPHIC INTERACTIONEVOLUTION, Issue 5 2007Timothy P. Craig The geographic mosaic theory of coevolution predicts that geographic variation in species interactions will lead to differing selective pressures on interacting species, producing geographic variation in the traits of interacting species (Thompson 2005). We supported this hypothesis in a study of the geographic variation in the interactions among Eurosta solidaginis and its natural enemies. Eurosta solidaginis is a fly (Diptera: Tephritidae) that induces galls on subspecies of tall goldenrod, Solidago altissima altissima and S. a. gilvocanescens. We measured selection on E. solidaginis gall size and shape in the prairie and forest biomes in Minnesota and North Dakota over an 11-year period. Galls were larger and more spherical in the prairie than in the forest. We supported the hypothesis that the divergence in gall morphology in the two biomes is due to different selection regimes exerted by natural enemies of E. solidaginis. Each natural enemy exerted similar selection on gall diameter in both biomes, but differences in the frequency of natural enemy attack created strong differences in overall selection between the prairie and forest. Bird predation increased with gall diameter, creating selection for smaller-diameter galls. A parasitic wasp, Eurytoma gigantea, and Mordellistena convicta, an inquiline beetle, both caused higher E. solidaginis mortality in smaller galls, exerting selection for increased gall diameter. In the forest there was stabilizing selection on gall diameter due to a combination of bird predation on larvae in large galls, and M. convicta - and E. gigantea- induced mortality on larvae in small galls. In the prairie there was directional selection for larger galls due to M. convicta and E. gigantea mortality on larvae in small galls. Mordellistena convicta- induced mortality was consistently higher in the prairie than in the forest, whereas there was no significant difference in E. gigantea- induced mortality between biomes. Bird predation was nonexistent in the prairie so the selection against large galls found in the forest was absent. We supported the hypothesis that natural enemies of E. solidaginis exerted selection for spherical galls in both biomes. In the prairie M. convicta exerts stabilizing selection to maintain spherical galls. In the forest there was directional selection for more spherical galls. Eurytoma gigantea exerted selection on gall shape in the forest in a complex manner that varied among years. We also supported the hypothesis that E. gigantea is coevolving with E. solidaginis. The parasitoid had significantly longer ovipositors in the prairie than in the forest, indicating the possibility that it has evolved in response to selection to reach larvae in the larger-diameter prairie galls. [source] Host plant effects on the development and survivorship of the galling insect Neopelma baccharidis (Homoptera: Psyllidae)AUSTRAL ECOLOGY, Issue 3 2002M. M. Espírito-Santo Abstract In this study, the mortality factors acting upon the galling psyllid Neopelma baccharidis Burckhardt (Homoptera) caused by its host plant, Baccharis dracunculifolia De Candole (Asteraceae) were analysed. In March 1999, 982 galls of the same cohort were randomly marked on 109 individuals of B. dracunculifolia in the field. Galls were censused each month during their development, from April to August, and dead galls were collected and analysed for mortality factors. Gall dehiscence rates were calculated for each month. The major mortality source of N. baccharidis was gall dropping (13.2% of the original cohort), which is probably a normal outcome of previous mortality caused by the other factors observed in this study. Unknown factors killed 11.7% of this gall population and were ascribed to plant resistance during gall development. Empty galls represented 7.7% of the observed mortality and may be a consequence of egg retention or egg mortality/abortion related to variations in plant quality. Shoot mortality was high during the dry season and killed 7.5% of the galls, but this impact was minimized after the third month from gall formation due to the ability of nymphs to accelerate development and emerge from galls on dying shoots. However, the size of dehisced galls on dead shoots tended to be smaller, possibly affecting adult performance. Mortality of N. baccharidis attributed to B. dracunculifolia strongly controlled the galling insect population, killing 40.7% of the original cohort of galls. Plant-mediated mortality was caused by often neglected factors acting predominantly during the first 3 months of development, which are critical to gall survivorship. These results reinforce the importance of bottom-up forces in plant-insect systems. [source] Seasonal phenology of the gall-making fly Fergusonina sp. (Diptera: Fergusoninidae) and its implications for biological control of Melaleuca quinquenerviaAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 4 2000John A Goolsby Abstract A gall-making fly, Fergusonina sp., is under study as a potential biological control agent of Melaleuca quinquenervia (Cav.) S. T. Blake, an invasive weed in Florida, USA. The seasonal phenology of Fergusonina sp. and its host M. quinquenervia was studied over 2 years in northern New South Wales and south-eastern Queensland. Fergusonina sp. populations followed an annual cycle, with gall numbers peaking in August/September. Gall density was strongly correlated with leaf bud density and temperature, but not rainfall. Comparison of climates in Australia across the native range of Fergusonina sp. with the climate of Miami, Florida, predicts that climate should not be a limiting factor in its establishment. The fly/nematode complex of Fergusonina/Fergusobia sp. is compared with other gall-making agents used in biological control programs. Galls are formed from primordial leaf bud and reproductive structures of the plant and have many of the attributes of a moderately powerful metabolic sink. High gall densities could potentially suppress seed production and reduce the vigour of the tree, which would make this insect species an effective biological control agent of M. quinquenervia. [source] Post-gall induction performance of Adelges Abietis (L.) (Homoptera: Adelgidae) is influenced by clone, shoot length, and density of colonising gallicolaeECOLOGICAL ENTOMOLOGY, Issue 1 2010LEAH FLAHERTY 1. We evaluated the effect of clone (one susceptible and one resistant clone), shoot length, crown level, and gallicola density on post-gall induction performance of Adelges abietis. Galls that had been successfully induced by one fundatrix on a range of shoot sizes were selected, and the number of gallicolae that could colonise the gall was manipulated. 2. Post-induction gall development success was inversely related to shoot length and was higher on the susceptible clone than on the resistant clone. As gallicola density did not influence the proportion of galls that successfully completed development, reduced post-induction gall development on large shoots was not likely to be result of an insufficient stimulus from gallicolae. 3. Clone was the only factor that significantly influenced gall volume and galls were larger on the susceptible clone than on the resistant clone. As gall volume did not increase when more gallicolae attempted to colonise a gall, competition within a gall increased. Gallicola survival was inversely related to the number of colonising gallicolae. Our results suggest that gall size may be limiting at natural densities. 4. Previous studies report positive relationships between gall induction success and fundatrix density, and between gall size and fundatrix density. As each fundatrix produces one egg mass of gallicolae, this study suggests that there may be a trade-off between the successful induction of a large gall and subsequent survival of gallicolae. 5. In the present study, clone influenced all measures of post-gall induction performance. Performance was always higher on the susceptible than on the resistant clone. [source] Stem galls affect oak foliage with potential consequences for herbivoryECOLOGICAL ENTOMOLOGY, Issue 3 2004L. K. Foss Abstract., ,1. On two dates, foliar characteristics of pin oak, Quercus palustris, infested with stem galls caused by the horned oak gall, Callirhytis cornigera, were investigated, and the consequences for subsequent herbivory assessed. 2. Second-instar caterpillars of the gypsy moth, Lymantria dispar, preferred foliage from ungalled trees. 3. Ungalled trees broke bud earlier than their galled counterparts. 4. Galled trees produced denser leaves with higher nitrogen and tannin concentrations, but foliar carbohydrates did not differ among galled and ungalled trees. 5. Concentrations of foliar carbohydrates in both galled and ungalled trees increased uniformly between the two assay dates. Nitrogen concentrations were greater in leaves from galled trees, and decreased uniformly in galled and ungalled trees over time. Foliar tannins were also greater in foliage from galled trees early in the season; however, foliar tannins declined seasonally in galled tissue so that by the second assay date there was no difference in tannin concentrations between galled and ungalled foliage. 6. In spite of differences in foliar characteristics, performance of older, fourth instar gypsy moth caterpillars did not differ between galled and ungalled trees. [source] Skewed sex ratios and multiple founding in galls of the oak apple gall wasp Biorhiza pallidaECOLOGICAL ENTOMOLOGY, Issue 1 2003Rachel J. Atkinson Abstract. 1. The gall wasp Biorhiza pallida (Hymenoptera: Cynipidae) reproduces by cyclical parthenogenesis. The adults of the sexual generation develop within galls (oak apples) that contain many larval cells. 2. Folliot [(1964) Annales Des Sciences Naturelles: Zoologie, 12, 407,564] found asexual generation females to be of three reproductive types. Androphores produce only sons, gynophores produce only daughters, and gynandrophores produce both sons and daughters. In nature, most oak apples give rise to either only males or only females but a proportion produces both sexes. These mixed-sex galls could result either from eggs laid by one or more gynandrophores or from eggs laid by androphores and gynophores developing within a single gall (multiple founding). 3.,Here the frequency of mixed- and single-sex galls was quantified, and morphological and genetic analyses were carried out on the adults emerging from 10 galls to determine the frequency of multiple founding in B. pallida. 4. Seventy-five per cent of 627 galls yielded only one sex. The majority of the remaining 25% had a highly skewed sex ratio. Low genetic variation in B. pallida limited the application of allozyme-based genetic techniques, however seven of the 10 galls analysed in detail, including mixed-sex galls, appeared to have been multiply founded. Contributions by the different foundresses in multiply founded galls were highly skewed. 5. The significance of multiple founding is discussed in the light of possible adaptive scenarios (reduction of parasitoid-induced mortality, avoidance of local stochastic extinction and inbreeding) and possible competition for oviposition sites. [source] Plants, gall midges, and fungi: a three-component systemENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2008Odette Rohfritsch Abstract Larvae of gall midges (Diptera: Cecidomyiidae) induce the activation of plant cells, partial cell lysis, and differentiation of nutritive tissue. Specialized nutritive tissue is essential for larval development and plays a key role in gall organization. Midges of the tribes Lasiopterini and Asphondyliini, however, do not induce nutritive tissues as part of the formation of their galls. Instead, these ,ambrosia galls' contain fungal mycelia that line the interior surface of the chambers. The fungi not only provide Lasiopterini with nutrition, they also penetrate the stems, induce the lysis of the middle lamella of host cells, and open a channel to the vascular bundles. Larvae of Lasioptera arundinis (Schiner) (Lasiopterini) follow the fungus and feed on its mycelium along with adjoining stem cells of Phragmites australis (Cav.) Trin. (Poaceae). Eggs together with fungal conidia are deposited by the imago on the host. Asphondyliini use a needle-like ovipositor to introduce fungal conidia and eggs into the organs they attack. Larvae of Schizomyia galiorum Kieffer (Asphondyliini) are unable to initiate the gall or to develop in the flowers of Galium mollugo L. (Rubiaceae) without their fungal associate. In this article, I provide an overview of oviposition behaviour in the Asphondyliini, as well as descriptions of the ovipositor and the female post-abdominal segments. Gall formation by Lasiopterini and Asphondyliini and the role of associated fungi are discussed, as is the role of the fungus as an inquiline or an organizer of gall tissues and a nutritive device. [source] Is gall size a good indicator of adelgid fitness?ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2001Stephanie L. Sopow First page of article [source] Female reproductive biology of Platygaster diplosisae (Hymenoptera: Platygastridae) and Aprostocetus procerae (Hymenoptera: Eulophidae), two parasitoids associated with the African Rice Gall Midge, Orseolia oryzivora (Diptera: Cecidomyiidae)ENTOMOLOGICAL SCIENCE, Issue 2 2008Souleymane NACRO Abstract We investigated the female reproductive system of Platygaster diplosisae (Hymenoptera: Platygastridae) and Aprostocetus procerae (= Tetrastichus pachydiplosisae) (Hymenoptera: Eulophidae), two parasitoids associated with the African rice gall midge, Orseolia oryzivora (Diptera: Cecidomyiidae). Both optical and electron microscopy were used. The female reproductive system of P. diplosisae includes two large ovaries of the meristic polytrophic-type, each composed of several tens of ovarioles. The system includes also a venomous gland that extends to a common oviduct. This gland had a filiform secretory portion, in which the epithelium was thin and surrounded a common evacuation canal. The secretory cells secrete into a large reservoir. Parasitism due to P. diplosisae is gregarious. The female reproductive system of A. procerae includes two ovaries of the meristic polytrophic-type, and each ovary has a few ovarioles. Each ovariole includes one or two oocytes, which can be seen in the vitellarium. Two accessory glands, which extend to the oviduct, are also visible. The secretory epithelium of the accessory gland is made up of a dense network of secretory cells surrounded by muscle fibers. Females of A. procerae pierce the tissues of the gall and probably deposit one egg on or close to the pupa of the midge. Aprostocetus procerae is a solitary parasitoid of the midge. The two parasitoids exploit the same host at different developmental stages. These findings improve our knowledge of the reproductive biology of these two parasitoids associated with the African rice gall midge, an important pest in Africa. [source] Moths boring into Ficus syconia on Iriomote Island, south-western JapanENTOMOLOGICAL SCIENCE, Issue 2 2004Shinji SUGIURA Abstract Herbivory in the syconia of six Ficus (Moraceae) species (F. superba, F. varieagata, F. virgata, F. irisana, F. bengutensis and F. septica) was examined in March 2002 on Iriomote Island, south-western Japan. Larvae of two lepidopteran species, Pachybotys spissalis (Guenée) (Pyralidae: Pyraustinae) and Stathmopoda sp. (Stathmopodidae) were observed to bore into the Ficus syconia. The attack rate by the moths varied from 0 to 38.5% across Ficus trees. The interiors of the syconia were heavily grazed by the moth larvae. Because figs (syconia) can be regarded as galls and seeds, according to sex and developmental stage, the moth larvae could be considered as gall or seed herbivores, and predators of fig wasps. Moth attack in the Ficus syconia could cause the destruction of fig wasp populations, as fig wasps develop in the syconia. [source] Susceptibility of source plants to Sugarcane Fiji disease virus influences the acquisition and transmission of the virus by the planthopper vector Perkinsiella saccharicidaJOURNAL OF APPLIED ENTOMOLOGY, Issue 1 2006K. Dhileepan Abstract:, Fiji leaf gall (FLG) caused by Sugarcane Fiji disease virus (SCFDV) is transmitted by the planthopper Perkinsiella saccharicida. FLG is managed through the identification and exploitation of plant resistance. The glasshouse-based resistance screening produced inconsistent transmission results and the factors responsible for that are not known. A series of glasshouse trials conducted over a 2-year period was compared to identify the factors responsible for the erratic transmission results. SCFDV transmission was greater when the virus was acquired by the vector from a cultivar that was susceptible to the virus than when the virus was acquired from a resistant cultivar. Virus acquisition by the vector was also greater when the vector was exposed to the susceptible cultivars than when exposed to the resistant cultivar. Results suggest that the variation in transmission levels is due to variation in susceptibility of sugarcane cultivars to SCFDV used for virus acquisition by the vector. [source] Anticaries effect of compounds extracted from Galla Chinensis in a multispecies biofilm modelMOLECULAR ORAL MICROBIOLOGY, Issue 6 2008Q. Xie Introduction:,Galla Chinensis is a leaf gall known to have some antibacterial effects. Using an in vitro biofilm model of dental plaque, the present study aimed to evaluate the anticaries effects of Galla Chinensis and its chemical fractions. Methods:, A four-organism bacterial consortium (Streptococcus sanguis, Streptococcus mutans, Actinomyces naeslundii, Lactobacillus rhamnosus) was grown on hydroxyapatite (HA) discs, bovine enamel blocks, and glass surfaces in a continuous culture system and exposed to repeated solution pulses. Galla Chinensis extracts, sucrose solutions, and sodium fluoride solutions were pulsed into different flow cells. The pH value of the planktonic phase in each flow cell was recorded and the bacteria colonizing the biofilm on the HA discs were counted. Enamel blocks were observed using a polarized microscope and lesion depth was evaluated. The biofilm morphology was examined with a fluorescence microscope and the images captured were analyzed on an image analysis system. Results:, When Galla Chinensis extract, its chemical fraction, or fluoride was added to the sucrose solution, the planktonic phase pH remained higher than that in the sucrose alone. A lower level of colonization on the HA surface was also observed in the groups to which Galla Chinensis and fluoride were added compared with the control sucrose group, and this was reflected in both the total viable count and the biofilm imaging, which showed fewer cariogenic bacteria and a less compact biofilm, respectively. Enamel demineralization in both the fluoride group and the Galla Chinensis group was significantly less than that in the sucrose group. Conclusions:,Galla Chinensis and fluoride may inhibit the cariogenicity of the oral biofilm. Galla Chinensis appears to be a promising source of new agents that may prevent dental caries. [source] DNA and protein transfer from bacteria to eukaryotes, the agrobacterium storyMOLECULAR PLANT PATHOLOGY, Issue 1 2000The 18th Bateson Memorial Lecture Agrobacterium is a well-studied plant pathogen, which has the unique ability to transfer DNA and protein into a number of eukaryotes. The DNA is integrated randomly into the plant genome where it is expressed, thereby leading to the disease crown gall. This system is a paradigm for the interaction of a number of plant and animal pathogens which transfer proteins into their host cells. In Agrobacterium, the tumour inducing (Ti) plasmid codes for the functions specifically required for the transfer process. These genes, termed virulence or vir genes, are activated by plant signal molecules acting through a two component regulatory system. A key structure coded by 11 genes of the vir B operon is a pilus, synthesized at 20 °C, but poorly at 25 °C. How this pilus functions in DNA and protein transfer is unclear, but homologous genes are found in many animal pathogens. In addition to Ti plasmid-encoded vir genes, chromosomal virulence genes have also been identified. However, these mutations are often pleiotropic because they involve both the normal physiology of Agrobacterium as well as the metabolism of Agrobacterium when it is associated with plant cells. Based on 16S ribosomal RNA sequencing, Agrobacterium is closely related to the intracellular pathogen of animals, Brucella. Several chromosomal mutations of Agrobacterium required for virulence in plants are also required for invasion of animal host cells by Brucella. [source] Evidence of pAgK84 transfer from Agrobacterium rhizogenes K84 to natural pathogenic Agrobacterium spp. in an Italian peach nurseryPLANT PATHOLOGY, Issue 4 2009A. Raio Nine Italian peach nurseries, which use Agrobacterium rhizogenes strain K84 to protect plants from crown gall, were monitored for three years with the aim of determining whether transconjugant populations may arise following plasmid exchanges between K84 and autochtonous soil agrobacteria. Six hundred and seventy-eight Agrobacterium isolates were obtained from 120 tumours developed on apricot and peach rootstocks that had been treated in pre-planting with the antagonist. Agrobacteria were characterized for pathogenicity, biovar, opine catabolism and agrocin 84 sensitivity. Colony hybridization was used for screening the isolates harbouring plasmids pTi and/or pAgK84. Analysis of plasmid content and Southern blotting were performed on putative transconjugant agrobacteria found in tumours collected from one nursery where a biological control breakdown was observed. The RFLP analysis of 16S + IGS regions showed that pAgK84 was transferred from the antagonist to virulent and avirulent soil agrobacteria belonging to different ribotypes. Pathogenic transconjugants, inoculated on GF677 rootstocks, were not controlled in vivo by K84 and stably maintained pTi and pAgK84 in the bacterial cells for at least one year. At the end of a biocontrol trial, new transconjugant tumorigenic agrobacteria originated by the transfer of pAgK84 to the pathogen. Virulent and avirulent transconjugants may represent a real threat for biological control by K84 strain since all of them produced agrocin and were insensitive to it. Survival in soil of these populations could make the future application of K84 ineffective. [source] Characterization of agrobacteria from weeping fig (Ficus benjamina)PLANT PATHOLOGY, Issue 5 2001A. Zoina Ficus benjamina plants, galled both at epi- and hypogeous parts, were observed in Italy and in The Netherlands, and these were the first records of the appearance of weeping fig crown gall in Europe. A total of 241 Agrobacterium isolates was obtained from 41 tumours and studied for their morphological, physiological and phytopathological characters. Two main groups of agrobacteria were distinguished by their colony morphology and through classical biovarietal tests that allowed allocation of 86 isolates into biovar 1 and 155 into an intermediate biovar rather different from any of the three biovars defined for agrobacteria. Most of the isolates were unable to utilize mannopine, nopaline or octopine as C and N sources; only 62 strains utilized nopaline. However, when nonopine-utilizing strains were inoculated into F. benjamina, only nopaline was detected in the developing tumours. BIOLOG ML 1Ô system analysis applied to 50 representative strains allowed identification of the biovar 1 isolates as Agrobacterium tumefaciens and most of the intermediate biovar isolates as the newly proposed species Agrobacterium fici. Analysis of sensitivity to a set of 14 antibiotics confirmed the allocation of the 50 strains into two well defined main clusters matching the BIOLOG identification. Out of 141 tumorigenic isolates, 66 were sensitive in vitro to agrocine 84, but four of these strains showed scarce or no sensitivity to the antagonist A. radiobacter K84 when tested in fig plants. The two types of agrobacteria could usually be isolated from the same tumours. Tumorigenic strains were able to induce tumours in six herbaceous plant species, in eight to 10 out of 12 woody plants and in six to eight out of nine Ficus species, indicating a wide host-range Ti plasmid. Agrobacteria were able to survive and move in the vascular system of galled ficus plants and to induce tumour growth in stem-cutting propagated plants. Moreover, agrobacteria were detected in many healthy F. benjamina plants as part of the endophytic microflora. These findings suggest potential for spread of the disease through latently infected plant propagation material produced as cuttings or by tissue culture. [source] Diversity of host plant relationships and leaf galling behaviours within a small genus of thrips ,Gynaikothrips and Ficus in south east Queensland, AustraliaAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 4 2009Desley J Tree Abstract Thrips are well known as gall inducers, yet no field studies have been published on phlaeothripids in the genus Gynaikothrips, which gall Ficus leaves in Australia. A detailed field study was conducted in suburban Brisbane, Australia, on thrips species that induce leaf galls on fig trees. Gynaikothrips ficorum is evidently host specific as it induced leaf galls only on Ficus microcarpa, and did so almost continuously throughout the spring and summer growing season. By contrast, G. australis induced leaf galls on F. macrophylla, F. rubingosa and F. obliqua but only when flushes of new leaves appeared, and this occurred at intervals during spring and summer. Gynaikothrips ficorum feeds on the upper surface of new leaves and this causes the leaf to fold and/or twist into a gall. The life of the gall is about 4 weeks, with the thrips pupating within it. Sometimes, the galls are invaded by a kleptoparasite thrips, Mesothrips jordani. Gynaikothrips australis feeds on the underside of the new leaves and this causes the margins to curl under. The life of the gall is about 6 weeks, with the thrips pupating under the bark of the fig tree branches, and sometimes the galls are shared with an inquiline, G. additamentus. [source] Patterns of interspecific associations of stem gallers on willowsDIVERSITY AND DISTRIBUTIONS, Issue 6 2003Jens-Peter Kopelke Abstract., The pattern of interspecific associations of three stem-galling sawfly species (Euura atra, E. elaeagnos, E. purpureae) and three stem-galling gallmidge species (Rabdophaga sp. 3,5) was investigated on five willow taxa (Salix alba, S. fragilis, S. × rubens, S. elaeagnos, S. purpurea) at five natural sites in Central Europe. The willow species harboured specific species associations of two stem gallers, each pair consisting of one Euura and one Rabdophaga species. The stem gallers were patchily distributed and their densities varied significantly among willow host plant species, host plant individuals, and host plant sexes. Four of the six species showed a significant increase in galling rate with shoot length. The other two species were the sawfly and cecidomyiid pair that induce galls on S. purpurea. The preference of stem gallers to longer shoots was generally not related to higher larval performance in terms of survival. Only one species, Rabdophaga sp. 5, was found to be more abundant on male plants. The correlation of densities of the species pairs of stem gallers was independent of willow sexes. Species pairs of stem gallers co-occurring on the same willow species tended to attack different shoots within the same host plant individual. When species pairs co-occurred on shoots they were usually found in similar densities as when occurring alone on shoots. The stem-galling sawflies usually formed galls at the basal part of a shoot, whereas the gallmidge R. sp. 5 (R. sp. 3 and R. sp. 4 showed no clear tendency) preferred the middle or distal part of a shoot. This is interpreted with differences of their phenology and oviposition period. [source] The earliest evidence of host,parasite interactions in vertebratesACTA ZOOLOGICA, Issue 2009evics, ns Luk Abstract Traces of parasite action have been discovered in the Middle,Upper Devonian fish from Estonia, Latvia and European Russia. Such traces are known in heterostracan Psammolepis venyukovi, antiarchs Asterolepis radiata and Bothriolepis ciecere, sarcopterygians Holoptychius sp., Ventalepis ketleriensis and Eusthenodon sp. nov. The traces include evidence of parasitic fixation and penetration as well as dwelling traces. Pathologies are developed as (1) round fossulae on the external surface of bones and scales; (2) oval fossulae with a slight elevation in the centre of the pit; (3) hollow swellings (possible galls); (4) openings (perforations) that have been repaired to various degrees; (5) variously shaped buttresses on the visceral surface of sarcopterygian scales; and (6) porous spongy formations on the non-overlapped surface of sarcopterygian scales. The round fossulae in sarcopterygian, placoderm and psammosteid skeletal elements could be produced by parasites that are similar to copepod crustaceans. Gall formation in Asterolepis is most likely to be caused by a larva, possibly of a trematode. The perforations of scales (and dermal bones) might arise from the attacks of ectoparasites (copepods?) or different worms. The spongy formations on the Holoptychius scales could be the result of invasion of a unicellular parasite. [source] Post-gall induction performance of Adelges Abietis (L.) (Homoptera: Adelgidae) is influenced by clone, shoot length, and density of colonising gallicolaeECOLOGICAL ENTOMOLOGY, Issue 1 2010LEAH FLAHERTY 1. We evaluated the effect of clone (one susceptible and one resistant clone), shoot length, crown level, and gallicola density on post-gall induction performance of Adelges abietis. Galls that had been successfully induced by one fundatrix on a range of shoot sizes were selected, and the number of gallicolae that could colonise the gall was manipulated. 2. Post-induction gall development success was inversely related to shoot length and was higher on the susceptible clone than on the resistant clone. As gallicola density did not influence the proportion of galls that successfully completed development, reduced post-induction gall development on large shoots was not likely to be result of an insufficient stimulus from gallicolae. 3. Clone was the only factor that significantly influenced gall volume and galls were larger on the susceptible clone than on the resistant clone. As gall volume did not increase when more gallicolae attempted to colonise a gall, competition within a gall increased. Gallicola survival was inversely related to the number of colonising gallicolae. Our results suggest that gall size may be limiting at natural densities. 4. Previous studies report positive relationships between gall induction success and fundatrix density, and between gall size and fundatrix density. As each fundatrix produces one egg mass of gallicolae, this study suggests that there may be a trade-off between the successful induction of a large gall and subsequent survival of gallicolae. 5. In the present study, clone influenced all measures of post-gall induction performance. Performance was always higher on the susceptible than on the resistant clone. [source] Gall wasps and their parasitoids in cork oak fragmented forestsECOLOGICAL ENTOMOLOGY, Issue 1 2007GUILLEM CHUST Abstract 1.,This paper explores the potential effects of host-plant fragmentation on cork oak gall wasp populations (Cynipidae, Hymenoptera) and on their predators, lethal inquilines, and parasitoids. To address this objective, galls were collected across a gradient of cork oak (Quercus suber) forest fragmentation in the East Pyrenees (Albera, Spain), and they were incubated to obtain the parasitism rates. 2.,Two hypotheses were tested: (1) Host-plant fragmentation may induce a decline in gall wasp populations because of area and isolation effects on local extinction and dispersal; as a consequence of that, parasitoids may decline even more strongly in fragmented habitats than their prey. (2) Host-plant fragmentation may cause a decline in gall wasp parasitoid populations that, in turn, can lead to an ecological release in their prey populations. 3.,Among the eight cork oak gall wasps sampled in the study area of Albera, the gall abundances of three species (Callirhytis glandium, Callirhytis rufescens, and Andricus hispanicus) were significantly related to forest fragmentation. The overall abundance of gall wasps was affected by a radius of , 890 m surrounding landscape, presenting constant abundances with forest loss until forest cover is reduced at , 40%; below that value the abundance increased rapidly. Three inquilines and 23 parasitoids species were recorded after gall incubation. In 25 cases, species of inquilines and parasitoids were newly recorded for the corresponding host in the Iberian peninsula. 4.,Although the overall parasitism rate was high (1.1), it was uncorrelated with fragmentation and with overall cynipid abundance. These results indicate that host-plant fragmentation was correlated with higher abundance of gall wasps, whereas the parasitism rate could not explain this hyper-abundance in small forest fragments. [source] Non-random distribution among a guild of parasitoids: implications for community structure and host survivalECOLOGICAL ENTOMOLOGY, Issue 6 2006ANTHONY M. ROSSI Abstract 1.,Immature stages of the gall midge, Asphondylia borrichiae, are attacked by four species of parasitoids, which vary in size and relative abundance within patches of the gall midge's primary host plant, sea oxeye daisy (Borrichia frutescens). 2.,In the current study, a bagging experiment found that the smallest wasp, Galeopsomyia haemon, was most abundant in galls exposed to natural enemies early in the experiment, when gall diameter is smallest, while the wasp with the longest ovipositor, Torymus umbilicatus, dominated the parasitoid community in galls that were not exposed until the 5th and 6th weeks when gall diameter is maximal. 3.,Moreover, the mean number of parasitoids captured using large artificial galls were 70% and 150% higher compared with medium and small galls respectively, while stem height of artificial galls significantly affected parasitoid distribution. Galls that were level with the top of the sea oxeye canopy captured 60% more parasitoids compared with those below the canopy and 50% more than galls higher than the plant canopy. 4.,These non-random patterns were driven primarily by the differential distribution of the largest parasitoid, T. umbilicatus, which was found significantly more often than expected on large galls and the smallest parasitoid of the guild, G. haemon, which tended to be more common on stems level with the top of the plant canopy. 5.,Large Asphondylia galls, especially those located near the top of the Borrichia canopy, were more likely to be discovered by searching parasitoids. Results using artificial galls were consistent with rates of parasitism of Asphondylia galls in native patches of sea oxeye daisy. Gall diameter was 19% greater and the rate of parasitism was reduced by almost 50% on short stems; as a result, gall abundance was 24% higher on short stems compared with ones located near the top of the plant canopy. 6.,These results suggest that parasitoid community composition within galls is regulated by both interspecific differences in ovipositor length and preferences for specific gall size and/or stem length classes. [source] Interactions between cottonwood and beavers positively affect sawfly abundanceECOLOGICAL ENTOMOLOGY, Issue 4 2006JOSEPH K. BAILEY Abstract 1.,Cottonwood (Populus spp.) are the dominant tree type in riparian forests of the western U.S.A. In these riparian forests, the beaver (Castor canadensis) is a major ecosystem engineer that commonly browses cottonwood, resulting in distinct changes to plant architecture. Here the hypothesis that beaver herbivory indirectly affects the distribution of a keystone leaf-galling sawfly through architectural changes in cottonwood was examined. 2.,It was found that: (a) beaver herbivory of cottonwood results in an increase in average shoot length over unbrowsed cottonwood; (b) sawfly galls were up to 7,14 times more abundant on browsed cottonwood than unbrowsed cottonwood; and (c) sawfly gall abundance was correlated positively with changes in shoot length after beaver herbivory. Together these data show that the individual and combined effects of cottonwood and beaver herbivory increase shoot length, positively affecting sawfly abundance. 3.,Because herbivores are a ubiquitous component of most ecosystems, we argue that the indirect effects of herbivory on plant quality, and subsequently other herbivores, may be as important as environmental variation. [source] Tritrophic interactions and trade-offs in herbivore fecundity on hybridising host plantsECOLOGICAL ENTOMOLOGY, Issue 3 2004Maria V. Cattell Abstract., 1. Interspecific plant hybridisation can have important evolutionary consequences for hybridising plants and for the organisms that they interact with on multiple trophic levels. In this study the effects of plant hybridisation on the abundance of herbivores and on the levels of herbivore parasitism were investigated. 2. Borrichia frutescens, B. arborescens, and their hybrid (B. × cubana) were censused for Asphondylia borrichiae galls and Pissonotus quadripustulatus plant hoppers in the Florida Keys. Levels of egg parasitism were determined by dissecting parental and hybrid stems and galls for herbivore and parasite eggs and larvae. Stem toughness and gall size are plant-mediated modes of protection from parasitism and these were also measured. For gall midges, fly size was measured as an estimate of fecundity. 3. Field censuses indicated that herbivore abundances varied on hybrid hosts relative to parent plant species and that the different herbivore species exhibited different patterns of abundance. Asphondylia borrichiae gall numbers followed the additive pattern of abundance while P. quadripustulatus numbers most closely resembled the dominance pattern. 4. Parasitism of P. quadripustulatus eggs was high on B. frutescens and the hybrids, and low on B. arborescens, which also had significantly tougher stems. Asphondylia borrichiae suffered the highest levels of parasitism on B. frutescens, the host plant which produced the smallest galls. On B. arborescens, which produced the largest galls, levels of A. borrichiae parasitism were lowest. Both parasitism and gall size were intermediate on the hybrid plants. Galls on B. arborescens and hybrid plants produced significantly smaller flies then those from B. frutescens suggesting that, when selecting hosts from among parent species and hybrids, gall flies may face a trade-off between escape from natural enemies and maximising fecundity. [source] | |||||||||||||||||||||||||||||||