Measuring air movement in small spaces: understanding air movement in historic bookshelves

The National Trust has tested ventilation holes in bookshelves to encourage air movement behind books as a possible strategy to improve the environment in these microclimates. This could be used as a preventive measure for mould development. Air movement was measured in historic bookshelves to understand what causes air movement and the impact of ventilation holes on the shelves behind books. Three libraries in National Trust properties were used as case studies. It was found that pressure differential and stack effect are two mechanisms contributing to the air velocities measured. However, several variables are believed to influence air movement in these small spaces, and further research is needed to understand its influence on mould development

Life table analysis of Diaphorina citri (Hemiptera: Psyllidae) infesting sweet orange (Citrus sinensis) in São Paulo

An ecological life table for eggs and nymphs of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) was constructed with data obtained from orange orchards (Citrus sinensis Osbeck) in 2 regions of the State of São Paulo, over 4 generations in the period from XI-2006 to V-2007, comprising spring, summer, and fall seasons. Young growing shoots with D. citri eggs present were identifed, and live individuals were counted until adult emergence. No predatory arthropods were observed in association with D. citri eggs and nymphs during the study. The mean parasitism of fourth- and ffth-instar nymphs by Tamarixia radiata Waterston (Hymenoptera: Eulophidae) was 2.3%. The durations of the egg–adult period were similar among the 4 generations, ranging from 18.0 to 24.7 d (at mean temperatures ranging from 21.6 to 26.0 °C) and followed the temperature requirement models obtained in the laboratory for D. citri. However, survival from the egg to the adult stage for the same period varied considerably from 1.7 to 21.4%; the highest mortalities were observed in the egg and small nymphal (frst- to thirdinstar) stages, which were considered to be key phases for population growth of the pest.Uma tabela de vida ecológica foi construída para ovos e ninfas de Diaphorina citri Kuwayama (Hemiptera: Psyllidae) com dados obtidos em pomares de laranja (Citrus sinensis Osbeck) em 2 regiões do estado de São Paulo, com 4 gerações, no período de novembro de 2006 a maio de 2007, compreendendo as estações de primavera, verão e outono. Ramos jovens em crescimento com a presença de ovos de D. citri foram identificados e os indivíduos vivos foram contados até a emergência dos adultos. Nenhum predador foi observado associado a ovos e ninfas de D. citri durante o estudo. A taxa média de parasitismo de ninfas de quarto e quinto ínstares por Tamarixia radiata Waterson (Hymenoptera: Eulophidae) foi de 2.3%. A duração do período de ovo a adulto foi semelhante entre as quatro gerações, variando de 18.0 a 24.7 dias (com temperaturas médias de 21.6 a 26.0 °C) e seguiram os modelos de exigencias térmicas obtidas em laboratório para D. citri. Todavia, a sobrevivencia de ovo até o estágio adulto variou consideravelmente para o mesmo período, de 1.7 a 21.4%, sendo que as maiores mortalidades foram observadas nos estágios de ovos e ninfas pequenas (de primeiro a terceiro ínstares), as quais foram consideradas fases chaves para o crescimento populacional desta praga.info:eu-repo/semantics/publishedVersio

Genome-wide analyses of Liberibacter species provides insights into evolution, phylogenetic relationships, and virulence factors.

'Candidatus Liberibacter' species are insect-transmitted, phloem-limited α-Proteobacteria in the order of Rhizobiales. The citrus industry is facing significant challenges due to huanglongbing, associated with infection from 'Candidatus Liberibacter asiaticus' (Las). In order to gain greater insight into 'Ca. Liberibacter' biology and genetic diversity, we have performed genome sequencing and comparative analyses of diverse 'Ca. Liberibacter' species, including those that can infect citrus. Our phylogenetic analysis differentiates 'Ca. Liberibacter' species and Rhizobiales in separate clades and suggests stepwise evolution from a common ancestor splitting first into nonpathogenic Liberibacter crescens followed by diversification of pathogenic 'Ca. Liberibacter' species. Further analysis of Las genomes from different geographical locations revealed diversity among isolates from the United States. Our phylogenetic study also indicates multiple Las introduction events in California and spread of the pathogen from Florida to Texas. Texan Las isolates were closely related, while Florida and Asian isolates exhibited the most genetic variation. We have identified conserved Sec translocon (SEC)-dependent effectors likely involved in bacterial survival and virulence of Las and analysed their expression in their plant host (citrus) and insect vector (Diaphorina citri). Individual SEC-dependent effectors exhibited differential expression patterns between host and vector, indicating that Las uses its effector repertoire to differentially modulate diverse organisms. Collectively, this work provides insights into the evolution of 'Ca. Liberibacter' species, the introduction of Las in the United States and identifies promising Las targets for disease management

Sampling and distribution pattern of Trioza erytreae Del Guercio, 1918 (Hemiptera: Triozidae) in citrus orchard

Developing efficient sampling protocols is essential to monitor crop pests. One vector of the citrus disease HLB, the African citrus psyllid Trioza erytreae Del Guercio, 1918 (Hemiptera: Triozidae), currently threatens the lemon industry throughout the Mediterranean region. In this work, a pool of sampling methods devoted to monitoring the population of T. erytreae was compared, its spatial distribution in the orchard was assessed, and the minimum sampling effort for the best sampling method was estimated. Three lemon orchards in North-western Portugal were sampled for one year using two types of yellow sticky traps (standard yellow and fluorescent Saturn yellow), B-vac sampling and sweep net sampling. The method that best performed, in terms of cost-efficiency, was the yellow sticky traps. The two colours of the sticky traps tested did not yield a significantly different number of catches. The spatial distribution throughout the orchards was found to be aggregated towards the borders. A minimum of three sticky traps per hectare was found to be enough to estimate the population at 90% accuracy for the mean during the outbreak. These results should help to monitor and anticipate outbreaks that may even colonize neighbour orchards. Studies on the local dispersion patterns of T. erytreae throughout the orchard are mandatory to further refine and optimize efficient monitoring protocols.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal), for financial support through national funds FCT/MCTES to CIMO (UIDB/00690/2020) and to the project PRE-HLB-Preventing HLB epidemics for ensuring citrus survival in Europe (H2020-SFS-2018-2 Topic SFS-05-2018-2019-2020, proj. No. 817526).info:eu-repo/semantics/publishedVersio

Optimization of Pathogenicity Tests for Selection of Native Isolates of Entomopathogenic Fungi Isolated from Citrusgrowing Areas of México on Adults ofDiaphorina citriKuwayama (Hemiptera: Liviidae)

Huanglonbing (HLB), es considerado una de las más letales enfermedades de los cítricos alrededor del mundo, y ha alcanzado las principales áreas de producción de limón Mexicano (Citrus latifolia Tanaka) en la costa del pacifico de México. Los productores han iniciado el uso de insecticidas para controlar las poblaciones del psílido asiático de los cítricos, Diaphorina citri Kuwayama (Hemiptera: Liviidae), el vector del patógeno ‘Candidatus Liberibacter asiaticus’ asociado con el HLB. Actualmente los costos de los insecticidas y los efectos secundarios de su uso son las principales preocupaciones, ya que podrían perjudicar la estrategia de manejo contra el vector; y por lo tanto, alternativas ecológicas y económicamente viables a los insecticidas convencionales serian necesarias a corto plazo. Por tanto, el objetivo de este estudio fue evaluar la patogenicidad de 27 aislados nativos y 3 cepas de hongos entomopatógenos para determinar su potencial como agentes de control biológico sobre Diaphorina citri usando 2 diferentes métodos de bioensayo. Los bioensayos fueron realizados bajo condiciones de laboratorio (26 ± 2 °C, 60 ± 5% H.R y 16:8 h L:O) mediante la exposición de insectos adultos a una concentración de 1 × 108 conidios por mililitro utilizando 2 diferentes métodos de aplicación, es decir, por asperjado de esporas en las plántulas de cítricos y por asperjado directo a los psílidos adultos. Los resultados mostraron que para el asperjado directo a los adultos los aislados HIB-24 (B. bassiana) y HIB-32 (I. fumosorosea) mostraron el mayor porcentaje de mortalidad (60.66%). Respecto al asperjado de plántulas el aislado HIB-19 (I. fumosorosea) mostró el mayor porcentaje de mortalidad (62.02%). Los resultados de este estudio demuestran el potencial para el uso de hongos entomopatógenos en el manejo de D. citri en México. ABSTRACT Huanglongbing (HLB), considered one of the most lethal diseases of citrus worldwide, has reached the main areas of Mexican lime (Citrus latifolia Tanaka) fruit production on the Pacific coast of México. Growers have initiated intensive use of insecticides in order to control populations of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), the vector of the pathogen, ‘Candidatus Liberibacter asiaticus’ associated with huanglongbing. Presently, costs of insecticides and the side effects of their use are major concerns, because they could impair the management strategy against the vector; and thus, ecologically and economically viable alternatives to conventional insecticides are required in the short term. Therefore the goal of this study was to evaluate the pathogenicity of 27 native isolates and 3 strains of entomopathogenic fungi and determine their potential as biological control agents of D. citri by using 2 different bioassay methods. Bioassays were performed under laboratory conditions (26 ± 2 °C, 60 ± 5% RH and 16:8 h L:D) by exposing adult insects to a concentration of 1 × 108 conidia per milliliter using 2 different application methods, i.e., spraying the spores onto the citrus seedlings and spraying the spores directly onto the adult psyllids. The results showed that by direct spraying the adults, HIB-24 (B. bassiana) and HIB-32 (I. fumosorosea) isolates showed the highest mortality (60.66%). Regarding spraying of the seedlings, HIB-19 (I. fumosorosea) showed the highest percentage of mortality (62.02%). The results from this study demonstrate potential for using entomopathogenic fungi in the management of D. citri in México

Orange jasmine as a trap crop to control Diaphorina citri

[EN] Novel, suitable and sustainable alternative control tactics that have the potential to reduce migration of Diaphorina citri into commercial citrus orchards are essential to improve management of huanglongbing (HLB). In this study, the effect of orange jasmine (Murraya paniculata) as a border trap crop on psyllid settlement and dispersal was assessed in citrus orchards. Furthermore, volatile emission profiles and relative attractiveness of both orange jasmine and sweet orange (Citrus¿×¿aurantium L., syn. Citrus sinensis (L.) Osbeck) nursery flushes to D. citri were investigated. In newly established citrus orchards, the trap crop reduced the capture of psyllids in yellow sticky traps and the number of psyllids that settled on citrus trees compared to fallow mowed grass fields by 40% and 83%, respectively. Psyllids were attracted and killed by thiamethoxam-treated orange jasmine suggesting that the trap crop could act as a `sink¿ for D. citri. Additionally, the presence of the trap crop reduced HLB incidence by 43%. Olfactometer experiments showed that orange jasmine plays an attractive role on psyllid behavior and that this attractiveness may be associated with differences in the volatile profiles emitted by orange jasmine in comparison with sweet orange. Results indicated that insecticide-treated M. paniculata may act as a trap crop to attract and kill D. citri before they settled on the edges of citrus orchards, which significantly contributes to the reduction of HLB primary spread.This work was supported by Fund for Citrus Protection (Fundecitrus) and by Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) (Proc. 2015/07011-3). We thank Moacir Celio Vizone, Felipe Marinho Martini and Joao Pedro Ancoma Lopes for technical support with experiments. Furthermore, we thank Cambuhy Agricola Ltda. and University of Araraquara (Uniara) for providing the areas in which the field experiments were performed. 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Crop Prot. 105, 10–15 (2018).Miranda, M. P. et al. Processed kaolin affects the probing and settling behavior of Diaphorina citri (Hemiptera: Liviidae). Pest Manag. Sci. 74, 1964–1972 (2018).Kobori, Y., Nakata, T., Ohto, Y. & Takasu, F. Dispersal of adult Asian citrus psyllid, Diaphorina citri Kuwayama (Homoptera: Psyllidae), the vector of citrus greening disease, in artificial release experiments. Appl. Entomol. Zool. 46, 27–30 (2011).Sétamou, M. et al. Diurnal patterns of flight activity and effects of light on host finding behavior of the Asian citrus psyllid. J. Insect Behav. 25, 264–276 (2012).Wenninger, E. J., Stelinski, L. L. & Hall, D. G. Roles of olfactory cues, visual cues, and mating status in orientation of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) to four different host plants. Environ. Entomol. 38, 225–234 (2009).Miranda, M. P., Dos Santos, F. L., Felippe, M. R., Moreno, A. & Fereres, A. Effect of UV-blocking plastic films on take-off and host plant finding ability of Diaphorina citri (Hemiptera: Liviidae). J. Econ. Entomol. 108, 245–251 (2015).Visser, J. H. Host odor perception in phytophagous insects. Annu. Rev. Entomol. 31, 121–144 (1986).Robbins, P. S., Alessandro, R. T., Stelinski, L. L. & Lapointe, S. L. Volatile profiles of young leaves of Rutaceae spp. varying in susceptibility to the Asian citrus psyllid (Hemiptera: Psyllidae). Florida Entomol. 95, 774–776 (2012).Fancelli, M. et al. Attractiveness of host plant volatile extracts to the Asian citrus psyllid, Diaphorina citri, is reduced by terpenoids from the non-host cashew. J. Chem. Ecol. 44, 397–405 (2018).Alquézar, B. et al. β-caryophyllene emitted from a transgenic Arabidopsis or chemical dispenser repels Diaphorina citri, vector of Candidatus Liberibacters. Sci. Rep. 7, 5639 (2017).Jones, R. A. C. Effects of cereal borders, admixture with cereals and plant density on the spread of bean yellow mosaic potyvirus into narrow‐leafed lupins (Lupinus angustifolius). Ann. Appl. Biol. 122, 501–518 (1993).Beloti, V. H., Alves, G. R., Coletta-Filho, H. D. & Yamamoto, P. T. The Asian citrus psyllid host Murraya koenigii is immune to citrus huanglongbing pathogen ‘Candidatus Liberibacter asiaticus’. Phytopathology 108, 1089–1094 (2018).Walter, A. J., Duan, Y. & Hall, D. G. Titers of ‘Ca. Liberibacter asiaticus’ in Murraya paniculata and Murraya-reared Diaphorina citri are much lower than in Citrus and Citrus-reared psyllids. HortScience 47, 1449–1452 (2012).Walter, A. J., Hall, D. G. & Duan, Y. P. Low incidence of ‘Candidatus Liberibacter asiaticus’ in Murraya paniculata and associated Diaphorina citri. Plant Dis. 96, 827–832 (2012).Ammar, E.-D. D., Ramos, J. E., Hall, D. G., Dawson, W. O. & Shatters, R. G. Acquisition, replication and inoculation of Candidatus Liberibacter asiaticus following various acquisition periods on huanglongbing-infected citrus by nymphs and adults of the Asian citrus psyllid. PLoS One 11, e0159594 (2016).Inoue, H. et al. Enhanced proliferation and efficient transmission of Candidatus Liberibacter asiaticus by adult Diaphorina citri after acquisition feeding in the nymphal stage. Ann. Appl. Biol. 155, 29–36 (2009).Pelz-Stelinski, K. S., Brlansky, R. H., Ebert, T. A. & Rogers, M. E. Transmission parameters for Candidatus Liberibacter asiaticus by Asian citrus psyllid (Hemiptera: Psyllidae). J. Econ. Entomol. 103, 1531–1541 (2010).Canale, M. C. et al. Latency and persistence of ‘Candidatus Liberibacter asiaticus’ in its psyllid vector, Diaphorina citri (Hemiptera: Liviidae). Phytopathology 107, 264–272 (2017).Li, W., Hartung, J. S. & Levy, L. 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Conservation of Gene Order and Content in the Circular Chromosomes of ‘Candidatus Liberibacter asiaticus’ and Other Rhizobiales

‘Ca. Liberibacter asiaticus,’ an insect-vectored, obligate intracellular bacterium associated with citrus-greening disease, also called “HLB," is a member of the Rhizobiales along with nitrogen-fixing microsymbionts Sinorhizobium meliloti and Bradyrhizobium japonicum, plant pathogen Agrobacterium tumefaciens and facultative intracellular mammalian pathogen Bartonella henselae. Comparative analyses of their circular chromosomes identified 514 orthologous genes shared among all five species. Shared among all five species are 50 identical blocks of microsyntenous orthologous genes (MOGs), containing a total of 283 genes. While retaining highly conserved genomic blocks of microsynteny, divergent evolution, horizontal gene transfer and niche specialization have disrupted macrosynteny among the five circular chromosomes compared. Highly conserved microsyntenous gene clusters help define the Rhizobiales, an order previously defined by 16S RNA gene similarity and herein represented by the three families: Bartonellaceae, Bradyrhizobiaceae and Rhizobiaceae. Genes without orthologs in the other four species help define individual species. The circular chromosomes of each of the five Rhizobiales species examined had genes lacking orthologs in the other four species. For example, 63 proteins are encoded by genes of ‘Ca. Liberibacter asiaticus’ not shared with other members of the Rhizobiales. Of these 63 proteins, 17 have predicted functions related to DNA replication or RNA transcription, and some of these may have roles related to low genomic GC content. An additional 17 proteins have predicted functions relevant to cellular processes, particularly modifications of the cell surface. Seventeen unshared proteins have specific metabolic functions including a pathway to synthesize cholesterol encoded by a seven-gene operon. The remaining 12 proteins encoded by ‘Ca. Liberibacter asiaticus’ genes not shared with other Rhizobiales are of bacteriophage origin. ‘Ca. Liberibacter asiaticus’ shares 11 genes with only Sinorhizobium meliloti and 12 genes are shared with only Bartonella henselae

Sexual Transmission of a Plant Pathogenic Bacterium, Candidatus Liberibacter asiaticus, between Conspecific Insect Vectors during Mating

Candidatus Liberibacter asiaticus is a fastidious, phloem-inhabiting, gram-negative bacterium transmitted by Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae). The bacterium is the presumed causal agent of huanglongbing (HLB), one of the most destructive and economically important diseases of citrus. We investigated whether Las is transmitted between infected and uninfected D. citri adults during courtship. Our results indicate that Las was sexually transmitted from Las-infected male D. citri to uninfected females at a low rate (<4%) during mating. Sexual transmission was not observed following mating of infected females and uninfected males or among adult pairs of the same sex. Las was detected in genitalia of both sexes and also in eggs of infected females. A latent period of 7 days or more was required to detect the bacterium in recipient females. Rod shaped as well as spherical structures resembling Las were observed in ovaries of Las-infected females with transmission electron microscopy, but were absent in ovaries from uninfected D. citri females. The size of the rod shaped structures varied from 0.39 to 0.67 µm in length and 0.19 to 0.39 µm in width. The spherical structures measured from 0.61 to 0.80 µm in diameter. This investigation provides convincing evidence that a plant pathogenic bacterium is sexually transmitted from male to female insects during courtship and established evidence that bacteria persist in reproductive organs. Moreover, these findings provide an alternative sexually horizontal mechanism for the spread of Las within populations of D. citri, even in the absence of infected host trees

The Complete Genome Sequence of ‘Candidatus Liberibacter solanacearum’, the Bacterium Associated with Potato Zebra Chip Disease

Zebra Chip (ZC) is an emerging plant disease that causes aboveground decline of potato shoots and generally results in unusable tubers. This disease has led to multi-million dollar losses for growers in the central and western United States over the past decade and impacts the livelihood of potato farmers in Mexico and New Zealand. ZC is associated with ‘Candidatus Liberibacter solanacearum’, a fastidious alpha-proteobacterium that is transmitted by a phloem-feeding psyllid vector, Bactericera cockerelli Sulc. Research on this disease has been hampered by a lack of robust culture methods and paucity of genome sequence information for ‘Ca. L. solanacearum’. Here we present the sequence of the 1.26 Mbp metagenome of ‘Ca. L. solanacearum’, based on DNA isolated from potato psyllids. The coding inventory of the ‘Ca. L. solanacearum’ genome was analyzed and compared to related Rhizobiaceae to better understand ‘Ca. L. solanacearum’ physiology and identify potential targets to develop improved treatment strategies. This analysis revealed a number of unique transporters and pathways, all potentially contributing to ZC pathogenesis. Some of these factors may have been acquired through horizontal gene transfer. Taxonomically, ‘Ca. L. solanacearum’ is related to ‘Ca. L. asiaticus’, a suspected causative agent of citrus huanglongbing, yet many genome rearrangements and several gene gains/losses are evident when comparing these two Liberibacter. species. Relative to ‘Ca. L. asiaticus’, ‘Ca. L. solanacearum’ probably has reduced capacity for nucleic acid modification, increased amino acid and vitamin biosynthesis functionalities, and gained a high-affinity iron transport system characteristic of several pathogenic microbes

International collaborative study to assess cardiovascular risk and evaluate long-term health in cats with preclinical hypertrophic cardiomyopathy and apparently healthy cats:The REVEAL Study

Background: Hypertrophic cardiomyopathy is the most prevalent heart disorder in cats and principal cause of cardiovascular morbidity and mortality. Yet, the impact of preclinical disease is unresolved. Hypothesis/Objectives: Observational study to characterize cardiovascular morbidity and survival in cats with preclinical nonobstructive (HCM) and obstructive (HOCM) hypertrophic cardiomyopathy and in apparently healthy cats (AH). Animals: One thousand seven hundred and thirty client-owned cats (430 preclinical HCM; 578 preclinical HOCM; 722 AH). Methods: Retrospective multicenter, longitudinal, cohort study. Cats from 21 countries were followed through medical record review and owner or referring veterinarian interviews. Data were analyzed to compare long-term outcomes, incidence, and risk for congestive heart failure (CHF), arterial thromboembolism (ATE), and cardiovascular death. Results: During the study period, CHF, ATE, or both occurred in 30.5% and cardiovascular death in 27.9% of 1008 HCM/HOCM cats. Risk assessed at 1, 5, and 10 years after study entry was 7.0%/3.5%, 19.9%/9.7%, and 23.9%/11.3% for CHF/ATE, and 6.7%, 22.8%, and 28.3% for cardiovascular death, respectively. There were no statistically significant differences between HOCM compared with HCM for cardiovascular morbidity or mortality, time from diagnosis to development of morbidity, or cardiovascular survival. Cats that developed cardiovascular morbidity had short survival (mean \ub1 standard deviation, 1.3 \ub1 1.7 years). Overall, prolonged longevity was recorded in a minority of preclinical HCM/HOCM cats with 10% reaching 9-15 years. Conclusions and Clinical Importance: Preclinical HCM/HOCM is a global health problem of cats that carries substantial risk for CHF, ATE, and cardiovascular death. This finding underscores the need to identify therapies and monitoring strategies that decrease morbidity and mortality