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

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collected GWSS material to the experimental site – basically, many of the GWSS nymphs died or left the tested host plant almost immediately after being transfer. We are currently improving inoculation techniques. Objective 2 – Natural Enemies During the surveys of GWSS population dynamics in non-agricultural regions, described previously, we collected information on GWSS natural enemies, using sampling techniques such as GWSS egg mass collections (>100 leaves per perennial plant species per collection) and potential GWSS predator collections (beat and sweep samples). As in all studies, we recorded host plant species and seasonal period. We found Gonatocerus ashmeadi and G. triguttatus (Triapitsyn et al. 1998) comprised about 95 and 4%, respectively, of collected parasitoids. As has been suggested, these parasitoids kill >90% of the summer GWSS population. Parasitoid numbers drop during the winter, when most GWSS are in the adult stage – although large nymphs were present as well. No egg masses or recently hatched nymphs were found from November through February. The first fresh egg masses were collected in April (2003) and March (2004), and we found parasitized eggs within as soon as April (2004). Our results suggest that egg parasitoids are the primary biological control factor. Combined with the winter / spring area wide insecticide control programs (which dramatically reduce the over-wintered population on citrus, the primary GWSS host plant during this period, and lower the overall GWSS population levels in the SJV) the egg parasitoids reduce the GWSS population in the urban regions to such an extent that GWSS can be difficult to find in large numbers in late summer samples. Predators may play a small role controlling GWSS nymphs. Spiders were the most common predator found, and there was a 2 significantly positive relationship between the number of spiders found and the number of GWSS egg masses (P < 0.001, rP P= 0.28). Still, there has not yet been any concrete evidence that links these generalist predators with the regulation or suppression of GWSS. During the GWSS urban surveys, predators were collected, identified to family or genus, and stored at -80ºC. These specimens have been shipped to the Western Cotton Research Laboratory, where the predator gut content is being assayed with immunologically-based assays that employ pest-specific monoclonal antibodies (MAbs) for the presence of GWSS egg protein using the ELISA by Drs. Hagler, Fournier and Leon (Hagler et al. 2003). These studies will provide direct evidence of predation by generalist predators. Objective 3 - Xylella How important are glassy-winged sharpshooter populations in the urban regions as vectors of Xf in nearby agricultural areas? First, GWSS population densities have been relatively low in the SJV urban centers, as previously described. Second, GWSS has a relatively low Xf transmission efficiency. Together, the low density and poor transmission efficiency would suggest few GWSS would have Xf in their mouthparts and play any role in the movement of the pathogen. We tested adult GWSS collected from ornamental plants in Bakersfield and, to our surprise, found Xf in GWSS (mouthparts) collected from oleander, Xylosma, and Chinese elm. The positive results do not necessarily mean that the GWSS acquired the Xf from the plants that they were collected on as the adults move between host plants often. How important are GWSS nymphs in the movement of Xf among ornamental plants and to vineyards? Nymphs shed the lining of their gut with each molt before adulthood, loosing any Xf living there and therefore provide a better indication of acquisition. The initial screening of GWSS nymphs used a “presence” or “absence” of groups of nymphs collected and therefore data are presented as such, rather than a percentage. In the initial collections, Xf was found only in GWSS nymphs collected from oleander (in the Bakersfield region). It is also important to note that all GWSS samples testing positive for Xf were analyzed for bacterial strain differences and analyses showed that the bacteria present are not of the PD type, but could be oleander, almond, oak, peach or plum. Most likely the Xf is oleander strain, which does not pose an immediate threat to nearby vineyards because this strain does not cause PD in grapes CONCLUSIONS We have described GWSS population density and age structure on ornamental plants common in residential landscaping in the SJV. We have further described natural enemy presence. This research can be added to information collected in Riverside and Ventura counties to help predict GWSS movement and develop control programs. The research has broader implications for use of ornamental landscape and riparian plants within agricultural settings (e.g., landscaping around farm buildings and homes). Plants which act as preferred hosts for both vector and pathogen can be target for control. By testing GWSS for the presence of Xf, researchers will identify potential sources of the pathogen, thereby preventing potential epidemic spread of Pierce’s disease causing Xf throughout a reservoir of ornamental host plants. To see a list of host plants, for both Xf and GWSS) go to: TUhttp://nature.berkeley.edu/xylellaUT. - 95 -
GWSS per 30 s sweep (seasonal average) 4 3 2 1 0 Pink Lady Kaiser Permanente 2003-04 Wheeler’s dwarf GWSS 1 st –2 nd instars GWSS 3 rd –4 th instars GWSS 5 th instars GWSS adults Escallonia Star jasmine Abelia Flowering Pear Crab Apple Oleander Xylosma Figure 1. The seasonal average for host plant preference GWSS adults and nymphs was clearly towards oleander and Xylosma at this sampling site. Data of the seasonal average are skewed by the large spring GWSS population density. GWSS per plant 5 4 3 2 1 0 a Ivy Figure 1 a Gardenia a ab ab ab ab Privet Hibiscus Photinia Euonymus Citrus bc cd d Agapanthus Eucalyptus Oleander d d Crape Myrtle Grapes Figure 2. Average densities (± SEM) of GWSS (nymphs and adults) were significantly different among perennial host plants, Tukey’s HSD at P < 0.05. Data are seasonal averages, and biased towards host species preferred in June and July, when GWSS densities were the highest. REFERENCES Hagler, J., K. Daane, and H. Costa. 2003. Progress on the development of a monoclonal antibody specific to glassy-winged sharpshooter egg protein: a tool for predator gut analysis and early detection of pest infestation. In M. Athar Tariq et al. [eds.], Proceedings, Pierce’s Disease Research Symposium. Calif. Dept. Food and Agricul., Digital Logistix, Sacramento, CA. Daane, K. M., M. W. Johnson 2003. Biology and Ecology of the glassy-winged sharpshooter in the San Joaquin Valley In M. Athar Tariq et al. [eds.], Proceedings, Pierce’s Disease Research Symposium. Calif. Dept. Food and Agricul., Digital Logistix, Sacramento, CA. Daane, K. M., M. W. Johnson, T. Ruiz, T., and J. Hashim. 2004a. Research shows GWSS have their urban preferences. Kern/Tulare GWSS Update. March 5, 2004. Daane, K. M., E. Shapland, T. Ruiz, M. W. Johnson, and J. Hashim. 2004b. Identifying the role of weeds in the overwintering of Xylella. Kern/Tulare GWSS Update. April 20, 2004. Shapland, E., K. M. Daane, G. Y. Yokota, A. H. Purcell, C. Wistrom, M. W., Johnson. 2004c. Researchers follow Xylella pathways. Kern/Tulare GWSS Update. August 6, 2004. Triapitsyn S. V., R. F. Mizell III, J. L. Bossart, and C. E. Carlton. 1998. Egg parasitoids of Homalodisca coagulata (Homoptera: Cicadellidae). Fl. Entomol. 81: 241-243. FUNDING AGENCIES Funding for this project was provided by the CDFA Pierce’s Disease and Glassy-winged Sharpshooter Board. - 96 -
Page 1 and 2: IMPACT OF HOST PLANT XYLEM FLUID ON
Page 3 and 4: 0.18 600 Optical density 0.16 0.14
Page 5 and 6: OPTIMIZING MARKER-ASSISTED SELECTIO
Page 7 and 8: esistant and susceptible genotypes
Page 9 and 10: MAP BASED IDENTIFICATION AND POSITI
Page 11 and 12: esistant genotypes are in process a
Page 13 and 14: BREEDING PIERCE’S DISEASE RESISTA
Page 15 and 16: Progeny from crosses of field resis
Page 17 and 18: a = (1=low, 4= high); b = (1=green,
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Page 23 and 24: v.8) for differences due to the pla
Page 25 and 26: SHARPSHOOTER FEEDING BEHAVIOR IN RE
Page 27 and 28: correlated with all other findings
Page 29 and 30: EFFECTS OF FEEDING SUBSTRATE ON RET
Page 31 and 32: REFERENCES Bextine, B. and T. Mille
Page 33 and 34: will also provide insights into the
Page 35: OBJECTIVES 1. Determine glassy-wing
Page 39 and 40: ELISA for the presence of GWSS egg
Page 41 and 42: Project Leader: Thomas P. Freeman E
Page 43 and 44: Freeman, T. P., R. A. Leopold, D. R
Page 45 and 46: pathogen, when they move into viney
Page 47 and 48: 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
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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
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EFFECTS OF SUBLETHAL DOSES OF IMIDA
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Table 2. Mortality and flight perfo
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A NOVEL METHOD TO INDUCE OVIPOSITIO
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REFERENCES Brodbeck, B. V., P. C. A
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Cohorts H. coagulata neonates were
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REFERENCES Blua, M. J. and D. J. W.
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Figure 2 shows the average numbers
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REPRODUCTIVE BIOLOGY AND PHYSIOLOGY
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REFERENCES Blua, M. J., Phillips, P
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RESULTS Some plant families had no
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Table 5. Winter, spring and summer
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16S rDNA is by far the most sequenc
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DNA MICROARRAY AND MUTATIONAL ANALY
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Inhibition of biofilm is BSA concen
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CULTURE-INDEPENDENT ANALYSIS OF END
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Borneman, J., M. Chrobak, G. Della
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P (CFU P OBJECTIVE 1. Determine the
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Purcell, AH and SR Saunders. 1999a.
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Figure 1: Southern blot of tolC::ap
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Project Leader: David Gilchrist Dep
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III. Production of transgenic plant
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RESULTS Construction of cDNA Librar
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CONCLUSIONS Genetic resistance and
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Mutagenesis of Xylella The EZ::TN T
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ISOLATION OF BACTERIOPHAGES SPECIFI
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Project Leader: Michele M. Igo Sect
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outer membrane fractions using two-
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1995; Purcell and Saunders, 1999).
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DEVELOPMENT OF SSR MARKERS FOR GENO
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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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