Short-term Effects of Remedial Surgery to Restore Productivity to Eutypa lata Infected Vines

Eutypa dieback, caused by the wood infecting fungus Eutypa lata, causes a gradual decline in vineyard production. Many growers renew infected vines by removing infected wood. Here we report on the short-term effects of the procedure on 28-year-old own-rooted Shiraz vines. In spring 1999, all vines in six adjacent rows were examined for foliar symptoms of Eutypa dieback. The following winter, cuts were made through both cordons and the trunk of each vine to determine the extent of wood discolouration, a symptom of E. lata infection. Foliar symptoms were recorded on 35% of the 141 vines, yet discoloured wood was observed in all cuts made through the cordons and in 71% of cuts made through the trunk. However, no association was found between the foliar symptoms observed in the spring prior to surgery and the extent of wood discolouration, i.e. discolouration that was visible on the cut surface of the trunk (P=0.20). Furthermore, discoloured wood remaining in the trunk had no effect on the production of watershoots (P=0.74), which were produced by 63% of vines in 2000. When re-examined in spring 2001 and 2002, watershoots were observed on 61 and 76% of vines respectively. As in the previous year, no association was observed between the discoloured wood remaining in the trunk and the production of watershoots (P=1.00 in 2001, P=0.21 in 2002). Foliar symptoms were not observed in 2000, 2001 nor in 2002. Infection with E. lata was confirmed by isolation of the pathogen from 92% of discoloured wood samples taken from 14 vines

Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV

The elliptic, $v_2$, triangular, $v_3$, and quadrangular, $v_4$, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions and (anti-)protons in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range $|\eta|<0.8$ at different collision centralities and as a function of transverse momentum, $p_{\rm T}$, out to $p_{\rm T}=20$ GeV/$c$. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for $p_{\rm T}>8$ GeV/$c$. The small $p_{\rm T}$ dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to $p_{\rm T}=8$ GeV/$c$. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least $p_{\rm T}=8$ GeV/$c$ indicating that the particle type dependence persists out to high $p_{\rm T}$.Comment: 16 pages, 5 captioned figures, authors from page 11, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186

System size dependence of associated yields in hadron-triggered jets

We present results on the system size dependence of high transverse momentum di-hadron correlations at $\sqrt{s_{NN}}$ = 200 GeV as measured by STAR at RHIC. Measurements in d+Au, Cu+Cu and Au+Au collisions reveal similar jet-like correlation yields at small angular separation ($\Delta\phi\sim0$, $\Delta\eta\sim0$) for all systems and centralities. Previous measurements have shown that the away-side yield is suppressed in heavy-ion collisions. We present measurements of the away-side suppression as a function of transverse momentum and centrality in Cu+Cu and Au+Au collisions. The suppression is found to be similar in Cu+Cu and Au+Au collisions at a similar number of participants. The results are compared to theoretical calculations based on the parton quenching model and the modified fragmentation model. The observed differences between data and theory indicate that the correlated yields presented here will provide important constraints on medium density profile and energy loss model parameters.Comment: 12 pages, 5 figure

Energy dependence of charged pion, proton and anti-proton transverse momentum spectra for Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV

We study the energy dependence of the transverse momentum (pT) spectra for charged pions, protons and anti-protons for Au+Au collisions at \sqrt{s_NN} = 62.4 and 200 GeV. Data are presented at mid-rapidity (|y| < 0.5) for 0.2 < pT < 12 GeV/c. In the intermediate pT region (2 < pT < 6 GeV/c), the nuclear modification factor is higher at 62.4 GeV than at 200 GeV, while at higher pT (pT >7 GeV/c) the modification is similar for both energies. The p/pi+ and pbar/pi- ratios for central collisions at \sqrt{s_NN} = 62.4 GeV peak at pT ~ 2 GeV/c. In the pT range where recombination is expected to dominate, the p/pi+ ratios at 62.4 GeV are larger than at 200 GeV, while the pbar/pi- ratios are smaller. For pT > 2 GeV/c, the pbar/pi- ratios at the two beam energies are independent of pT and centrality indicating that the dependence of the pbar/pi- ratio on pT does not change between 62.4 and 200 GeV. These findings challenge various models incorporating jet quenching and/or constituent quark coalescence.Comment: 19 pages and 6 figure

Eradication of black rot (Guignardia bidwellii) from grapevines by drastic pruning

A drastic pruning strategy was developed to eradicate the fungal disease black rot (Guignardia bidwellii), which is exotic in Australia, from grapevines, while minimizing the economic cost of returning an affected vineyard to its previous quality and production levels. The protocol involved cutting off vines at the top of the trunk, removing debris from the ground beneath and between vines, mulching the vineyard floor, removing low watershoots during vine regrowth and applying a targeted fungicide programme. The protocol was initially evaluated and consequently modified in Australia using an endemic grapevine disease, black spot or anthracnose (Elsinoe ampelina), as an analogous model system. Then, it was validated in a black‐rot‐infested vineyard in New York, USA. Following two seasons of disease‐conducive weather conditions, no black rot was detected on treated vines, whereas leaf and fruit infections developed on the untreated control vines. These results confirmed the efficacy of the protocol for eradicating black rot from vineyards while allowing vines to return quickly to previous yield and quality levels without replanting. The protocol may have applicability to disease eradication protocols for other perennial crops as well. Evidence is also presented on the efficacy and potential pitfalls of burning infected grapevine material to eradicate E. ampelina.M. R. Sosnowski, R. W. Emmett, W. F. Wilcox, T. J. Wick

Interaction between <em>Eutypa lata</em> and <em>Trichoderma harzianum</em>

Metabolites produced by three strains of Trichoderma harzianum reduced growth of Eutypa lata in vitro. Volatile metabolites produced by T. harzianum were fungistatic towards both isolates of E. lata tested. Growth of some isolates of E. lata was inhibited completely by non-volatile metabolites. Infection by E. lata was reduced in autoclaved grapevine cane segments co-inoculated with spores of T. harzianum and E. lata. Scanning electron microscopic examination of gamma-irradiated cane segments and living cuttings inoculated with T. harzianum and E. lata suggested that antagonism in grapevine wood was mainly by antibiosis. Both the pathogen and the antagonist grew in the xylem vessels and pith parenchyma cells of the wood

An evaluation of biological and abiotic controls for grapevine powdery mildew. 2. Vineyard trials

Copyright © 2008 Australian Society of Viticulture and Oenology Inc.Grapevine powdery mildew (Erysiphe necator) affects grape yield and fruit quality worldwide. Managers of conventional vineyards rely mainly on synthetic fungicides and sulfur to control powdery mildew, while in organic vineyards sulfur is the main control agent, often in rotation with canola-based oils, bicarbonates and biological control agents. The efficacy of those materials has not been evaluated critically under field conditions in Australia. Accordingly, a range of materials showing most promise in previous greenhouse trials (Crisp et al. 2006 Australian Journal of Grape and Wine Research 12, pp. 192-202) were assessed via field trials in commercial vineyards. Applications of either milk or whey (alone, or mixed with a canola oil-based product), as well as applications of potassium bicarbonate (commercial formulation), all reduced the severity of powdery mildew compared with untreated vines. Eight applications of a 1:10 dilution of milk, 45 g/L whey powder or programs comprising rotations of potassium bicarbonate plus oil and whey, applied at 10-14 day intervals, reduced the severity of powdery mildew to levels not significantly different from that on vines sprayed with sulfur (wettable powder, 3-6 g/L). However, the relative control of powdery mildew by the test materials in field trials was dependent on the susceptibility of the grapevine cultivar and the extent of spray coverage achieved. In vineyards where highly susceptible cultivars were planted, and spray coverage was compromised, the resultant control of powdery mildew was reduced; and sometimes to commercially unacceptable levels.P. Crisp, T.J. Wicks, D. Bruer and E.S. Scot