Susceptibility to Botrytis blight at different floral stages of wild blueberry phenotypes

Botrytis blossom blight is an important disease of wild blueberries with yield losses in excess of 20% frequently occurring. Two field experiments were conducted in 2016 and 2017 to determine the susceptibility of four phenotypes (Vaccinium angustifolium, V. angustifolium f. nigrum, V. myrtilloides and V. angustifolium var. Fundy] at different floral stages [(Bud break (F5); bud prebloom; (F6), corolla fully open (F7), and senescent corolla (F8)] to Botrytis infection. Specific flower clusters on tagged stems from different phenotypes were inoculated with Botrytis cinerea conidial suspension (106 conidia·ml-1). Disease development were assessed eight days after inoculation. Disease incidence and severity in phenotype ranged from 14.1 to 22.6% and 37.4 to 42.3% in 2016, respectively, and 39.8 to 44.1% and 9.70 to 19.1% in 2017, respectively. Results indicated that V. angustifolium was the most susceptible followed by V. angustifolium f. nigrum and V. angustifolium var. Fundy. Vaccinium myrtilloides was found to be least susceptible. Incidence and severity on floral stages ranged from 2.95 to 36.4% and 7.81 to 75.5% in 2016, respectively, and 7.28 to 66.9% and 11.1 to 27.1% in 2017, respectively. Floral stage F7 was the most susceptible with incidence up to 66.9% and severity up to 75.5% followed by F6, F5 and F8. Therefore, results from this study indicated that V. myrtilloides was less susceptible to B. cinerea than V. angustifolium phenotypes, and F6 and F7 stages were the most susceptible to Botrytis blight. These results will assist producers in making more informed decisions on Botrytis blight control and as its management practices shift from blanket to precise delivery of disease control products

\u3cem\u3eMonilinia vaccinii-corymbosi\u3c/em\u3e sensitivity to demethylation inhibitor fungicides and its effect on Monilinia blight control in wild blueberry fields

Monilinia vaccinii-corymbosi (Reade) Honey (M.vc), the causal agent of Monilinia blight of wild blueberry, is controlled primarily by fungicide applications. Demethylation-inhibiting fungicides (DMIs) have been used for over 30 years for Monilinia blight control due to flexibility of use (i.e., ability to use after an infection period) and disease control effectiveness and consistency. In the present study, the sensitivity of ten M.vc isolates to three DMIs- propiconazole, difenoconazole and prothioconazole-desthio were evaluated in vitro by a mycelial growth inhibition assay. In addition, four field trials were conducted during two crop seasons: 2012 and 2013, to examine the efficacy of these DMIs to control Monilinia blight. All the tested DMIs were effective in inhibiting mycelial growth of M.vc isolates, although the mean EC50 values differed significantly. In field experiments, three of four trials had significant treatment effect on disease incidence and severity of vegetative buds. Prothioconazole-desthio and propiconazole provided consistent control against Monilinia blight. Conversely, difenoconazole was effective in in vitro analysis, but did not demonstrate satisfactory Monilinia blight control in all field trials. In the 2012 trials, both prothioconazole-desthio and propiconazole reduced disease incidence of vegetative buds by 100% compared to the untreated control. Prothioconazole- desthio reduced disease development in 2013 with 94 and 99.8% less incidence, and 75 and 99.5% less severity. Similarly, propiconazole also reduced incidence of vegetative buds by 88% and 99.8%, and severity by 54% and 99.7%. No phytotoxic symptoms were observed in any of the field trials. The results of the study serve as a benchmark to monitor shifts in M.vc sensitivity to these fungicides in the future

Eutipoza i ESCA bolesti odumiranja i sušenja čokota vinove loze u Srbiji

For a few years die off and wither symptoms of grapevines are massively present in some grapevine growing regions of Serbia. During 2006 and 2007 in grapevine growing region of Fruška Gora two groups of symptoms, which ultimately lead to dieback, have been documented. On localities Manđelos, Irig and Sremski Karlovci vines with specific bushy appearance have been recorded. The vines had small stunted shoots with short internodes and small cupped leaves. When an infected cordon or trunk is cut in cross-section a V-shaped, brown wedge of dead tissue can be seen (necrosis). After a few years with constant intensifying of growth stunting, vines at last do not develop shoots at all and completely die off. In comparison with authentic symptoms, the presence of dangerous disease determined as Eutypa dieback has been concluded and confirmed. After isolations from the perennial wood, fungus Eutypa lata causer of Eutypa dieback has been identified. Early detection of first recognizable symptoms on shoots has a great significance in Eutypa dieback management and control. On localities Manđelos and Sremski Karlovci, during summer months, massive and progressive withering of normally developed vines has been recorded. In comparison with authentic symptoms, detected presence of bright 'tiger striped' patterns on the leaves, as well as of roundish necrosis in central wood part, confirmed and proved the appearance of very destructive disease known as ESCA disease (or wither). Because of sudden and rapid drying up of whole vines, determination of this disease on the basis of symptoms has a great significance in order to prevent its spreading inside the vineyard, as early as possible. Symptom based determination of Eutypa dieback and ESCA disease has shown successful, but in case of Eutypa dieback special precaution is needed because sometimes similar simptoms can be caused by Botryosphaeria spp. Age structure of vineyards in Serbia is very poor and favorable for Eutypa dieback and ESCA disease appearance. Because of that fact, from year to year these two diseases have increasingly economical significance.Simptomi odumiranja i sušenja čokota vinove loze, već nekoliko godina, pojavljuju se u jakom intenzitetu u nekim vinogorjima Srbije. Tokom 2006. i 2007. godine, u fruškogorskom vinogorju dokumentovane su dve grupe simptoma, čiji je krajnji ishod sušenje čokota. Na lokalitetima Manđelos, Irig i Sremski Karlovci zapaženi su čokoti karakterističnog, žbunastog izgleda, sa malim, zaostalim lastarima sa skraćenim internodijama i sitnim, peharasto uvijenim listovima. Na poprečnom preseku drveta čokota uočene su braon, klinaste, 'V' nekroze. Nakon nekoliko godina sve izraženijeg zaostajanja organa u porastu, čokoti uopšte ne kreću sa vegetacijom i potpuno odumiru. Upoređivanjem sa referentnim simptomima, zaključeno je da se radi o pojavi veoma opasne bolesti drveta, koja je determinisana kao eutipoza vinove loze. Nakon izolacija iz višegodišnjeg drveta, identifikovan je i prouzrokovač Eutypa lata. Rano otkrivanje prvih prepoznatljivih simptoma na lastarima, ima veliki značaj u suzbijanju i kontroli eutipoze. Na lokalitetima Manđelos i Sremski Karlovci zabeleženo je masovno, progresivno sušenje normalno razvijenih čokota tokom letnjih meseci. Nakon upoređivanja sa referentnim simptomima, zabeleženo karakteristično 'tigar' prugasto šarenilo i sušenje lista, kao i kružna nekroza centralnog dela drveta, potvrdili su pojavu veoma destruktivne bolesti, koja je determinisana kao ESCA oboljenje (ili sušenje). Zbog iznenadnog i brzog sušenja celog čokota, determinacija ove bolesti, na osnovu simptoma, ima veliki značaj, kako bi se, što ranije, sprečilo njeno širenje u okviru vinograda. Simptomatološka determinacija eutipoze i ESCA oboljenja pokazala se kao uspešna, s tim da u slučaju eutipoze treba biti posebno oprezan, jer slične simptome ponekad mogu prouzrokovati i Botryosphaeria spp. Loša starosna struktura vinograda u Srbiji pogoduje pojavi eutipoze i ESCA oboljenja, koja, iz godine u godinu, imaju sve veći ekonomski značaj

Identification and molecular characterization of the blueberry stunt phytoplasma in Canada

Abstract Blueberry farms in Quebec, Canada, were recently surveyed for phytoplasma-associated disease presence. Farmers previously reported a number of high bush blueberries showing stunt symptoms in three blueberry farms. Bushes were tested for phytoplasma based on the 16S rRNA gene. Nested PCR with universal phytoplasma primers resulted in amplification of phytoplasma DNA from blueberry bushes in samples from two of the farms surveyed. The 16S rDNA of the blueberry stunt phytoplasma from Quebec showed a 99% sequence identity with that of the blueberry stunt phytoplasma from Michigan (AY265220) from group 16SrI 'Candidatus Phytoplasma asteris' subgroup 16SrI-E. Phylogeny results confirmed the clustering of the blueberry stunt phytoplasma from Quebec within the same phylogenetic branch of phytoplasmas of group 16SrI, closely related to subgroup 16SrI-E. Preliminary virtual RFLP confirmed the sequence and phylogeny classification results. Further actual and virtual analyses are in progress to verify the presence of other possible phytoplasma strains from the Quebec blueberry farms

Phylogenetic and experimental evidence for host-specialized cryptic species in a biotrophic oomycete

International audienceAssortative mating resulting from host plant specialization has been proposed to facilitate rapid ecological divergence in biotrophic plant pathogens. Downy mildews, a major group of biotrophic oomycetes, are prime candidates for testing speciation by host plant specialization. Here, we combined a phylogenetic and morphological approach with cross-pathogenicity tests to investigate host plant specialization and host range expansion in grapevine downy mildew. This destructive disease is caused by Plasmopara viticola, an oomycete endemic to North America on wild species and cultivated grapevines. Multiple genealogies and sporangia morphology provide evidence that P. viticola is a complex of four cryptic species, each associated with different host plants. Cross-inoculation experiments showed complete host plant specialization on Parthenocissus quinquefolia and on Vitis riparia, whereas cryptic species found on V. aestivalis, V. labrusca and V. vinifera were revealed to be less specific. We reconstructed the recent host range expansion of P. viticola from wild to cultivated grapevines, and showed that it was accompanied by an increase in aggressiveness of the pathogen. This case study on grapevine downy mildew illustrates how biotrophic plant pathogens can diversify by host plant specialization and emerge in agrosystems by shifting to cultivated hosts. These results might have important implications for viticulture, including breeding for resistance and disease management

Surveys reveal a complex association of phytoplasmas and viruses with the blueberry stunt disease on Canadian blueberry farms

Surveys for phytoplasmas and viruses were conducted during September 2014 and 2015 on highbush blueberry farms in the R\ue9gion Mont\ue9r\ue9gie, Quebec. Total DNA and RNA were extracted from blueberry bushes showing blueberry stunt (BBS) symptoms and from symptomless blueberry bushes, and utilised as templates for PCR and RT-PCR assays, respectively. Phytoplasma DNA was amplified with universal phytoplasma primers that target the 16S rRNA, secA and secY genes from 12 out of 40 (30%) plants tested. Based on 16S rRNA, secA and secY gene sequence identity, phylogenetic clustering, actual and in silico RFLP analyses, phytoplasma strains associated with BBS disease in Quebec were identified as \u2018Candidatus Phytoplasma asteris\u2019-related strains, closely related to the BBS Michigan phytoplasma strain (16SrI-E). The secY gene sequence-based single nucleotide polymorphism analysis revealed that one of the BBS phytoplasma strains associated with a leaf marginal yellowing is a secY-I RFLP variant of the subgroup 16SrI-E. Two viruses were detected in blueberry bushes. The Blueberry Red Ringspot Virus (BRRV) was found in a single infection in the cultivar Bluecrop with no apparent typical BRRV symptoms. The Tobacco Ringspot Virus (TRSV) was found singly infecting blueberry plants and co-infecting a BBS phytoplasma-infected blueberry cv. Bluecrop plant. This is the first report of TRSV in the cv. Bluecrop in Quebec. The Quebec BBS phytoplasma strain was identified in the leafhopper Graphocephala fennahi, which suggests that G. fennahi may be a potential vector for the BBS phytoplasma. The BBS disease shows a complex aetiology and epidemiology; therefore, prompt actions must be developed to support focused BBS integrated management strategies

Clean Plants for the Future of the Eastern Wine and Grape Industry

Based on the recent National Clean Plant Network (NCPN) webinar series, learn how the NCPN, new testing protocols and a revitalized New York certification program will reduce the risk of nursery-transmitted viral pathogens

Despite Slow Growth From 2005 to 2015, Independent Grocery Stores Remain Important for Rural Communities

In 2015, rural counties not adjacent to an urban county had an average of 2.1 independent grocery stores—whose owners operate fewer than four stores—compared with 1.9 chain grocery stores

The pattern of inflammatory markers during electroconvulsive therapy in older depressed patients

Objectives: An association is found between changes in cytokine levels and antidepressant treatment outcome. Also, a proinflammatory profile is associated with a favourable electroconvulsive therapy (ECT) outcome. This paper investigates the pattern of inflammatory markers during a course of ECT in older depressed patients and whether this pattern is associated with ECT outcome. We hypothesised that ECT has an anti-inflammatory effect. Methods: The pattern of CRP, IL-6, IL-10, and TNF-α during a course of ECT was examined using longitudinal mixed model analyses. Serum samples were collected in 99 older depressed patients (mean age: 72.8 ± 8.3 years, MADRS score 33.8 ± 9.0). Results: After Bonferroni correction, there were no statistically significant alterations in levels of inflammatory markers during and after ECT. Effect sizes (Cohen’s d) were −0.29 for CRP, −0.13 for IL-6, −0.06 for IL-10, and −0.07 for TNF-α. Changes in CRP or cytokine levels did not differ between remitters and non-remitters. Median baseline levels of CRP were significantly higher in remitters. Conclusions: A small to medium effect size towards decreased CRP and IL-6 levels was observed. An anti-inflammatory effect of ECT could not be confirmed. However, the findings may suggest that patients with an inflammatory profile benefit more from ECT than other patients. Further studies are needed to confirm these findings

Host floral scent mimicry by <i>Monilinia vaccinii-corymbosi</i> (<i>Mvc</i>) shoot strikes.

<p>Non-metric multidimensional scaling (NMDS) plot of volatile profiles from <i>Vaccinium corymbosum</i> flowers (red points), uninfected leaves (black), and leaves infected with <i>Mvc</i> (green). Total area occupied by each sample type as represented in 2-dimensional space is shaded in gray. Stress = 0.134. VOC profiles differed significantly among the three tissues sampled (pMANOVA <i>F</i>_2,28 = 8.1, <i>P</i> = 0.009), with healthy leaves differing from flowers (<i>F</i>_1,19 = 9.8, <i>P</i> = 0.009) and infected leaves (<i>F</i>_1,18 = 9.3, <i>P</i> = 0.010), while flowers vs. infected leaves were marginally, but not significantly different (<i>F</i>_1,18 = 3.0, <i>P</i> = 0.083).</p