Impact Of Host Plant Xylem Fluid On Xylella Fastidiosa Multiplication ...

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CONCLUSIONS Nearly 90% of the BGSS trapped in this study were caught on traps at 15 feet or lower. This suggests that barriers could have a significant impact on reducing the numbers of BGSS entering vineyards. However, this may not be enough to have a major impact on reducing the incidence of PD. In addition, results from one tower indicated that BGSS may reside in some trees early in the season. This could allow for higher than normal flight activity, allowing more BGSS to enter vineyards by flying over a barrier. The effectiveness of barriers at reducing the incidence of PD will likely depend upon the nature of the adjacent riparian plant community, its mix of host plant species and the number of tall host trees. REFERENCES 1. Almeida, R.P.P. and A.H. Purcell. 2003. Transmission of Xylella fastidiosa to grapevines by Homalodisca coagulata (Hemiptera: Cicadellidae). J. Econ. Ent. 96(2):264-271. 2. Blua, M.J. and D.J.W. Morgan. 2003. Dispersion of Homalodisca coagulata (Hemiptera: Cicadellidae), a vector of Xylella fastidiosa, into vineyards in southern California. J. Econ. Ent. 96(5):1369-1374. 3. Feil, H., et al. 2000. Effects of temperature on the flight activity of Graphocephala atropunctata (Hemiptera: Cicadellidae). Journal of Economic Entomology 93(1): 88-92. 4. Goodwin, P., Purcell, A. H. 1992. Pierce's disease. Grape Pest Management, 2nd Edition. Oakland, University of California, Division of Agriculture and Natural Resources: 76-84. 5. Insley, E., et al. 2000. Riparian vegetation management for Pierce’s disease in North Coast California Vineyards. An information manual from the North Coast PD Task Force. 46pp. 6. Purcell, A.H. 1975. Role of the blue-green sharpshooter, Hordnia circellata, in the epidemiology of Pierce’s disease of grapevines. Env. Ent. 4:745-752. 7. Purcell, A.H. 1976. Seasonal changes in host plant preference of the blue-green sharpshooter Hordnia circellata. Pan- Pacific Ent. 52:33-37. 8. Purcell, A.H. 1979. Control of the blue-green sharpshooter and effects of spread of Pierce’s disease of grapevines. J. Econ. Ent. 72(6):887-892. 9. Purcell, A.H. 1981. Vector preference and inoculation efficiency as components of resistance to Pierce’s disease in European grape cultivars. Phytopath. 71(4):429-435. FUNDING AGENCIES Funding for this project was provided by the CDFA Pierce’s Disease and Glassy-winged Sharpshooter Board. - 159 -
REPRODUCTIVE BIOLOGY AND PHYSIOLOGY OF FEMALE GLASSY-WINGED SHARPSHOOTERS Project Leaders: Frank G. Zalom Dept. of Entomology University of California Davis, CA 95616 Cooperator: Nick C. Toscano Dept. of Entomology University of California Riverside, CA 92521 Christine Y. S. Peng Dept. of Entomology University of California Davis, CA 95616 Research Assistant: Natalie A. Hummel Dept. of Entomology University of California Davis, CA 95616 Reporting Period: The results reported here are from work conducted from January 2004 to September 2004. ABSTRACT Female and male GWSS have been collected from July 2001 to September 2004 at monthly or bimonthly intervals from citrus hosts at UC Riverside Agricultural Operations. A sub-sample of 10 females per month was dissected to determine ovary rank of the specimens collected. Dissections of these female specimens reveal repeated patterns related to the proportion of previtellogenic females in the field. These patterns indicate two distinct generations each year with a possible third generation late in the season. Sampling will conclude in December 2004, and analysis will be completed to develop a model of female vitellogenesis cycles. A host plant study, completed in the summer of 2002, in which adult male and female GWSS were caged on grape, citrus, and oleander, has suggested differences in female fecundity and offspring survival. This study is currently being repeated. SEM studies have been completed and found a large number of sensilla on the female ovipositor. Morphology of these sensilla suggests that they may have mechanosensory or chemosensory functions. Histological studies of the female reproductive organs at varying stages of vitellogenesis are currently being analyzed. INTRODUCTION The glassy-winged sharpshooter (GWSS), Homalodisca coagulata (Say), is a serious pest of many tree and vine crops (Turner and Pollard 1959, Nielson 1968). The GWSS is of primary concern to California growers because of its capacity to vector the bacterium, Xylella fastidiosa, which causes vascular disease in a number of crops, including grapes, citrus and almonds, as well as landscape plants including oleander and mulberries (Meadows 2001, Hopkins 1989, Purcell and Hopkins 1996). An adult GWSS need only acquire X. fastidiosa once while feeding on an infected plant to then become a vector of X. fastidiosa for the remainder of its life (Frazier 1965, Purcell 1979, and Severin 1949). Little is known about the reproductive biology of the GWSS. It has been reported that GWSS has two generations per year in Southern California (Blua et al. 1999). Oviposition occurs in late winter to early spring, and again in mid-to-late summer. Adult females can live several months and lay their eggs side by side in groups of about 10, ranging from 1 to 27 (Turner and Pollard, 1959). The greenish, sausage-shaped eggs are inserted into the leaf epidermis of the host plants. Our research is focused on the reproductive morphology and physiology of the GWSS. We are examining the seasonal differences in female GWSS reproduction between summer and overwintering populations by studying oögenesis cycles. This knowledge is important in determining how GWSS might choose plant hosts in the landscape, which host plants are particularly good for GWSS ovarian development and why they are good, and finally how control measures might best be implemented based upon season and stage of reproductive development. Better knowledge of reproductive biology might also lead to better decision support including improved choices and timing of chemical or non-chemical approaches to GWSS control. OBJECTIVES 1. Collect and prepare GWSS specimens for studying the morphology and anatomy of females. 2. Study and describe the sensory structures located on the female ovipositor. 3. Characterize the reproductive cycle of female GWSS in Riverside, California. 4. Study the effects of location on female GWSS reproductive cycle. 5. Study the effect of host plant type on female GWSS fecundity. RESULTS Oögenesis study Female and male GWSS have been collected from July 2001 to September 2004. Samples were taken on monthly or bimonthly intervals. Dissections of female specimens collected from citrus hosts at UC Riverside Agricultural Operations have revealed repeated patterns related to the proportion of previtellogenic females in the field (Figure 1). In 2004, oviposition activity began in January with peaks in oviposition activity occurring in April and July. The proportion of young - 160 -
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IMPACT OF HOST PLANT XYLEM FLUID ON
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0.18 600 Optical density 0.16 0.14
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OPTIMIZING MARKER-ASSISTED SELECTIO
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esistant and susceptible genotypes
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MAP BASED IDENTIFICATION AND POSITI
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esistant genotypes are in process a
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BREEDING PIERCE’S DISEASE RESISTA
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Progeny from crosses of field resis
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a = (1=low, 4= high); b = (1=green,
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v.8) for differences due to the pla
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SHARPSHOOTER FEEDING BEHAVIOR IN RE
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correlated with all other findings
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EFFECTS OF FEEDING SUBSTRATE ON RET
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REFERENCES Bextine, B. and T. Mille
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will also provide insights into the
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OBJECTIVES 1. Determine glassy-wing
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GWSS per 30 s sweep (seasonal avera
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ELISA for the presence of GWSS egg
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Project Leader: Thomas P. Freeman E
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Freeman, T. P., R. A. Leopold, D. R
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pathogen, when they move into viney
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A NOVEL IMMUNOLOGICAL APPROACH FOR
Page 49 and 50: 1.6 GWSS Adults That Fed on Protein
Page 51 and 52: Hagler, J.R. & S.E. Naranjo. 2004.
Page 53 and 54: RESULTS: Oviposition Survey Wild gr
Page 55 and 56: Host specificity testing: No-choice
Page 57 and 58: currently employed morphological ch
Page 59 and 60: increase our present understanding
Page 61 and 62: BIOLOGY AND MORPHOMETRIC ANALYSIS O
Page 63 and 64: Table 1. Mean a developmental durat
Page 65 and 66: EFFECTS OF USING CONSTANT AND CYCLI
Page 67 and 68: REFERENCES Gautam, R. D. 1986. Effe
Page 69 and 70: PARASITISM OF THE GLASSY-WINGED SHA
Page 71 and 72: Table 1. Parasitism by G.ashmeadi o
Page 73 and 74: Project Leader: Robert F. Luck Dept
Page 75 and 76: A more interesting analysis using t
Page 77 and 78: MYCOPATHOGENS AND THEIR EXOTOXINS I
Page 79 and 80: POPULATION DYNAMICS AND INTERACTION
Page 81 and 82: No egg masses were recorded on olea
Page 83 and 84: EXPLORATION FOR FACULTATIVE ENDOSYM
Page 85 and 86: Although Baumannia and Wolbachia we
Page 87 and 88: EFFECTS OF SUBLETHAL DOSES OF IMIDA
Page 89 and 90: Table 2. Mortality and flight perfo
Page 91 and 92: A NOVEL METHOD TO INDUCE OVIPOSITIO
Page 93 and 94: REFERENCES Brodbeck, B. V., P. C. A
Page 95 and 96: Cohorts H. coagulata neonates were
Page 97 and 98: REFERENCES Blua, M. J. and D. J. W.
Page 99: Figure 2 shows the average numbers
Page 103 and 104: REFERENCES Blua, M. J., Phillips, P
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Page 109 and 110: RESULTS Some plant families had no
Page 111 and 112: Table 5. Winter, spring and summer
Page 113 and 114: 16S rDNA is by far the most sequenc
Page 115 and 116: DNA MICROARRAY AND MUTATIONAL ANALY
Page 117 and 118: Inhibition of biofilm is BSA concen
Page 119 and 120: CULTURE-INDEPENDENT ANALYSIS OF END
Page 121 and 122: Borneman, J., M. Chrobak, G. Della
Page 123 and 124: P (CFU P OBJECTIVE 1. Determine the
Page 125 and 126: Purcell, AH and SR Saunders. 1999a.
Page 127 and 128: Figure 1: Southern blot of tolC::ap
Page 129 and 130: Project Leader: David Gilchrist Dep
Page 131 and 132: III. Production of transgenic plant
Page 133 and 134: RESULTS Construction of cDNA Librar
Page 135 and 136: CONCLUSIONS Genetic resistance and
Page 137 and 138: Mutagenesis of Xylella The EZ::TN T
Page 139 and 140: ISOLATION OF BACTERIOPHAGES SPECIFI
Page 141 and 142: Project Leader: Michele M. Igo Sect
Page 143 and 144: outer membrane fractions using two-
Page 145 and 146: 1995; Purcell and Saunders, 1999).
Page 147 and 148: DEVELOPMENT OF SSR MARKERS FOR GENO
Page 149 and 150: Strain Name Host of Origin County o
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ROLE OF ATTACHMENT OF XYLELLA FASTI
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wild-type cells was not conclusive
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DETERMINATION OF GENES CONFERRING H
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S1 S2 S3 S4 Nb123456789bb123456789b
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MULTILOCUS SEQUENCE TYPING TO IDENT
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GENOME-WIDE IDENTIFICATION OF RAPID
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Americas and since most of the plan
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EFFECTS OF CHEMICAL MILIEU ON ATTAC
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CONCLUSIONS Our overall objective i
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RESULTS Objective 1. We conducted t
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Redak, R. A., Purcell, A. H., Lopes
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In parallel, an “activating trans
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PATTERNS OF XYLELLA FASTIDIOSA INFE
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% of vessels 100 80 60 40 20 Mugwor
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DOCUMENTATION AND CHARACTERIZATION
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Magnolia002 showed more identity (9
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PLASMID ADDICTION AS A NOVEL APPROA
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GENETIC VARIABILITY OF XYLELLA FAST
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probing activities). In preliminary
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the slow release valve was opened a
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12. Hopkins DL (1977) Diseases caus
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The almost complete absence of info
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QUANTIFYING LANDSCAPE-SCALE MOVEMEN
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Table 1. The mean (±SD) ELISA read
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EPIDEMIOLOGICAL ASSESSMENTS OF PIER
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multiply to relatively high (easily
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SPATIAL DATABASE CREATION AND MAINT
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Project Leader: Thomas M. Perring D
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Figure 2. Individual leaves from a
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The state variables, process functi
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DEVELOPMENT OF A FIELD SAMPLING PLA
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Figure 1. Three main dispersion pat
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OBJECTIVES 1. Track the movement of
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REFERENCES 1. Beard, C.B., Cordon-R
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cases, positive phloem samples were
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EXPLOITING XYLELLA FASTIDIOSA PROTE
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Figure 2. Polymer disk accumulation
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CHARACTERIZATION OF NEONICOTINOIDS
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EVALUATION OF RESISTANCE POTENTIAL
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Project Leader: Doug Cook Dept. of
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Based on the in silico analysis, de
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CONTROL OF PIERCE’S DISEASE THROU
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Figure 1. Oleander ‘White’ afte
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RESULTS During the reporting period
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DEVELOPMENT OF AN ARTIFICIAL DIET A
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DESIGN OF CHIMERIC ANTI-MICROBIAL P
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Neutrophil elastase Cecropin B Chim
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and WTXb is very low (0.00-0.40%) a
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100 100 0.056 North America 100 0.0
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GENETIC DIFFERENTIATION AMONG GEOGR
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Table 1. Single-populations descrip
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MOLECULAR DISTINCTION BETWEEN POPUL
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These novel observations strongly s
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SEQUENCE DIVERGENCE IN TWO MITOCHON
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Table 3. Pairwise sequence distance
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DEVELOPMENT OF MOLECULAR DIAGNOSTIC
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A. B. Relative Density of SCAR Band
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THE ALIMENTARY TRACK OF GLASSY-WING
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We have dissected and identified al
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REALIZED LIFETIME PARASITISM AND TH
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REPRODUCTIVE AND DEVELOPMENTAL BIOL
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Mean adult longevity (days) 25 20 1
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the proposed exploratory work; thes
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SEARCHING FOR AND COLLECTING EGG PA
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REFERENCES Hoddle, M. S. and S. V.
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some Gram(+) bacteria, but are inac
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7. Hultmark, D., et al., Insect Imm
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Isolation of Fungal Pathogens Soil
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IDENTIFICATION OF MECHANISMS MEDIAT
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concentrations of 1.5 x 10 7 bacter
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anchor it in the outer membrane (sh
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SYMBIOTIC CONTROL OF PIERCE’S DIS
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MANAGEMENT OF PIERCE’S DISEASE OF
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pfF mutants are taken up by insects
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Simpson, A. J. G., F. C. Reinach, P
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Al-Wahaibi, A.K., Owen, and J. G. M
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patterns differed among the lines,
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Punja, Z.K. 2001. Genetic engineeri
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mind, we conducted an additional st
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REFERENCES Toscano, N., Byrne, F.,
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RESULTS AND CONCLUSIONS The program
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COMPATIBILITY OF INSECTICIDES WITH
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More tests are in progress to addre
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Impact Of Host Plant Xylem Fluid On Xylella Fastidiosa Multiplication ...

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