{"title":"Biological control of postharvest diseases of peach with phyllosphere isolates of Pseudomonas syringae","authors":"T. Zhou, J. Northover, K. Schneider","doi":"10.1080/07060669909501174","DOIUrl":"https://doi.org/10.1080/07060669909501174","url":null,"abstract":"Commercially ripe peaches were wounded and co-inoculated with phylloplane isolates of Pseudomonas syringae (MA-4 and NSA-6), Pseudomonas fluorescens (BAP-3), or an isolate of Candida sp. (NSD-4) in combination with either conidia of Monilinia fructicola (cause of brown rot) or sporangiospores of Rhizopus stolonifer (cause of rhizopus rot). Isolates NSA-6 and MA-4 at a concentration of 1 x 107 CFU/mL reduced brown rot to 28% and 73%, respectively, from 98% in the inoculated check after 5 days incubation at 22°C. Both isolates reduced rhizopus rot to 5% and 8% from 53% in the inoculated check after 5 days incubation. The P. syringae isolates when used in 2-min soak treatments were less effective against natural, preharvest M. fructicola infections of late-harvested peaches. Isolates MA-4 and NSA-6 suppressed brown rot from 63% to 30% and from 95% to 71-81%, respectively, after 3 and 4 days incubation at 22°C. The use of 0.5% CaCl2 in the soak suspension significantly improved the activity of P. syringae but...","PeriodicalId":9607,"journal":{"name":"Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73804312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Genetic diversity among Fusarium graminearum strains from Ontario and Quebec","authors":"M. Dusabenyagasani, D. Dostaler, R. Hamelin","doi":"10.1080/07060669909501196","DOIUrl":"https://doi.org/10.1080/07060669909501196","url":null,"abstract":"The random amplified polymorphic DNA (RAPD) method was used to sample DNA markers from 72 strains of Fusarium graminearum isolated from wheat blighted kernels collected from Quebec (52 strains), Ontario (18 strains), and Prince Edward Island (2 strains). Sixty-five markers generated with eight RAPD primers showed that all strains were genetically distinct. Moreover, the analysis of molecular variance (AMOVA) indicated that 90.56% of the genetic variability associated with strains used in this study was explained by within-region variation. The GST values were low and showed that there was almost no genetic differentiation associated with sampling F. graminearum either from two different years in Quebec (GST = 0.0375) or from Ontario and Quebec (GST = 0.0509). These results show that F. graminearum strains from Quebec and Ontario might be part of a single population pool.","PeriodicalId":9607,"journal":{"name":"Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85376755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"MOLECULAR STRATEGIES FOR ENGINEERING RESISTANCE TO POTATO VIRUSES","authors":"L. Kawchuk, D. Prüfer","doi":"10.1080/07060669909501186","DOIUrl":"https://doi.org/10.1080/07060669909501186","url":null,"abstract":"An increasing number of molecular strategies are available for engineering virus resistance in potatoes (Solatium tuberosum ssp. tuberosum L.) using pathogen-derived or other virus-inhibiting nucleic acid sequences and proteins. Virus resistance has been developed in transgenic plants expressing virus coat proteins, movement proteins, replicases, untranslatable sense or antisense RNAs, proteases, defective interfering RNAs, and satellites. Expression of ribozymes, a double-stranded RNA-specific ribonuclease, antiviral proteins, a plant pathogen resistance gene, and plantibodies has also provided virus resistance. Transgenic plants resistant to several viruses have already been approved by regulatory agencies for commercial release and virus-resistant potato varieties promise to improve yield and quality. Plant protection ranges from being specific against closely related strains of the virus to broad-spectrum resistance that extends to other virus groups. Progress has also been made in combining several s...","PeriodicalId":9607,"journal":{"name":"Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72808515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"CHV3-type dsRNAs and the GH2 genotype in a population of Cryphonectria parasitica in Ontario","authors":"M. S. Melzer, G. Boland","doi":"10.1080/07060669909501187","DOIUrl":"https://doi.org/10.1080/07060669909501187","url":null,"abstract":"CCP19, a hypovirulent isolate of Cryphonectria parasitica collected from a site near Bothwell, Ontario, in 1987, has shown potential for use in biological control of chestnut blight. CCP19 contains dsRNA that hybridizes with hypovirus CHV3 from isolate GH2 (CHV3-GH2), a hypovirulent isolate of C. parasitica from Michigan. In 1995, 26 isolates of C. parastica were collected at the Bothwell site, and 22-23 (85-89%) of these 26 isolates had significantly smaller lesion diameters in an apple virulence assay than virulent control isolate EP155. Twenty-two of the 26 isolates (85%) contained dsRNA. Segments of dsRNA in all 22 isolates hybridized with cDNA prepared from CHV3-type dsRNA in CCP19. The CHV3-type dsRNA was present in all three MCGs identified in the population. DNA fingerprint analysis revealed a highly clonal population, Twenty isolates had DNA fingerprint genotypes the same as, or similar to, GH2 and 6 isolates had genotypes similar to CCP19. Similarities, including presence of CHV3-type dsRNA, hig...","PeriodicalId":9607,"journal":{"name":"Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86290186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Rhizobacterial growth and yield promotion of cucumber plants inoculated with Pythium aphanidermatum","authors":"R. Utkhede, C. Koch","doi":"10.1080/07060669909501189","DOIUrl":"https://doi.org/10.1080/07060669909501189","url":null,"abstract":"The potential of rhizobacterial strains to reduce the adverse effects of Pythium aphanidermatum on plant growth and yield was examined under in vitro and greenhouse cropping conditions. Rhizobacterial cultures of 10 strains of Pseudomonas putida, 24 strains of Bacillus subtilis, 4 strains of Enterobacter aerogenes, 1 strain of Bacillus cereus, and 1 unknown bacterial strain were evaluated for antagonism against P. aphanidermatum in laboratory and greenhouse conditions. In a dual culture test on potato dextrose agar, only AG-1 of B. subtilis and strains 2xyta75 and B8 of E. aerogenes were antagonistic to P. aphanidermatum. Under sterile in vitro conditions in pouches, 40 bacterial strains were tested for growth promotion of cucumber (Cucumis sativus) seedlings in the absence of P. aphanidermatum. All bacteria except strain PPG-7-1 of P. putida, strains AGS-3 and AGS-1 of B. subtilis, and strain AG-0 of an unidentified bacterium increased root length of cucumber compared with the P. aphanidermatum inoculate...","PeriodicalId":9607,"journal":{"name":"Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77320049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Variation in culture and rDNA among isolates of Sphaeropsis sapinea from Ontario and Manitoba","authors":"G. Hausner, J. Reid, A. Hopkin, C. Davis","doi":"10.1080/07060669909501188","DOIUrl":"https://doi.org/10.1080/07060669909501188","url":null,"abstract":"Three morphotypes were recognized among Manitoba and Ontario isolates of Sphaeropsis sapinea. Variation in culture was assessed based on overall culture morphology, growth rates, and conidial characteristics. Morphotypes A and B conform to previously described morphotypes, but an intermediate morphotype with smooth conidia was designated as morphotype I. Morphotype A isolates were collected from a number of Pinus species as well as Picea pungens. Morphotype B was only recovered from Picea mariana on stressed sites in Ontario, and Pinus banksiana and Pinus resinosa in Manitoba. Morphotype I was recovered from Pinus species and Picea glauca. Restriction fragment length polymorphism analysis of the ribosomal repeat unit grouped the isolates into three classes, or ribotypes, which appear to correspond to the A, B, and 1 morphotypes. All three morphotypes have been collected in Ontario. Restriction fragment length polymorphism analysis of the rDNA repeat unit may therefore be useful in distinguishing Lhe diffe...","PeriodicalId":9607,"journal":{"name":"Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80735114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Xi, J. Helm, P. A. Burnett, T. Turkington, A. Tekauz
{"title":"Determining quantitative resistance of barley cultivars at the seedling stage to net blotch caused by Pyrenophora teres","authors":"K. Xi, J. Helm, P. A. Burnett, T. Turkington, A. Tekauz","doi":"10.1080/07060669909501192","DOIUrl":"https://doi.org/10.1080/07060669909501192","url":null,"abstract":"Four barley (Hordeum vulgare L.) cultivars, Heartland, Harrington, Johnston, and Kasota, were compared a: the seedling stage for reactions to the net and spot forms of net blotch caused by Pyrenophora teres f. teres and P. teres f. maculata, respectively. Effects of leaf wetness period, leaf position, and inoculum concentration on lesion development were investigated. The linear relationship between inoculum concentration and diseased leaf area was used to estimate inoculum concentrations causing 50% diseased leaf area (ED50) on leaf 2 (the second seedling leaf) and causing 15% diseased leaf area (ED15) on leaf 3 (third seedling leaf). Resistance of cultivars was compared on the basis of ED50 and ED15. The linear relationship of diseased leaf area with time was used to estimate the rate of lesion spread and to compare resistance. Lack of a significant linear relationship over time on leaf 3 for cvs. Heartland and Kasota inoculated with P. teres f. teres reflected resistance in these two cultivars. Both pa...","PeriodicalId":9607,"journal":{"name":"Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78711090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Influence of temperature, cultivar, and time on sporulation of Mycosphaerella fragariae on detached strawberry leaves","authors":"O. Carisse, B. Peyrachon","doi":"10.1080/07060669909501191","DOIUrl":"https://doi.org/10.1080/07060669909501191","url":null,"abstract":"The influence of temperature (5-35°C), cultivar (Chambly, Kent, Oka, Tribute) and temperature, and time (0-108 h) or> sporulation of Mycosphaerella fragariae was studied using a detached leaf assay. Sporulation was estimated as the number of conidia produced per lesion and transformed to relative sporulation. For all cultivars, except Oka, for which temperature was not significant, the highest sporulation occurred at 20°C and no sporulation was observed at 35°C. Relative sporulation varied with cultivar, Tribute being the most susceptible, followed by Kent and by Chambly with only few conidia per lesion. Sporulation started at 5°C, increased with increasing temperature up to 20°C, and then decreased. Relative sporulation was modeled using a second-order polynomial of temperature, and the models explained 85.7, 76.4, and 82.2% of the variation for cvs. Chambly, Kent, and Tribute, respectively. On cv. Tribute, less than 5% sporulation was obtained when leaves were exposed to wetness for 24 h or less. At tem...","PeriodicalId":9607,"journal":{"name":"Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78060496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"RESISTANCE TO POWDERY MILDEW IN GRAPEVINE INDUCED BY PLASMOPARA VITICOLA","authors":"M. Reuveni","doi":"10.1080/07060669909501190","DOIUrl":"https://doi.org/10.1080/07060669909501190","url":null,"abstract":"Prior inoculation of grapevine plants with the downy mildew fungus, Plasmopara viticola, induced a resistance to the powdery mildew fungus, Uncinula necator. Fourteen days after exposure to airborne conidia of U. necator, 1.5 and 23.9 colonies of powdery mildew per leaf developed on Plasmopara-inoculated and on control (noninoculated) plants, respectively. This resistance was confined to leaf tissues colonized by P. viticola and was not transferred to the new developing leaves. No protection was achieved when P. viticola failed to infect the plants. Microscopic examination indicated that conidia of U. necator could germinate on leaves infected with downy mildew, but could not produce secondary hyphae and colonies. This protection was reversed by the exogenous foliar application of 0.1% sucrose solution to leaves infected by P. viticola, which resulted in the restoration of susceptibility to powdery mildew. Application of a 0.1 % solution of sucrose enhanced the development of U. necator on both water-trea...","PeriodicalId":9607,"journal":{"name":"Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85935667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Managing fungal diseases of potato","authors":"G. Secor, N. Gudmestad","doi":"10.1080/07060669909501184","DOIUrl":"https://doi.org/10.1080/07060669909501184","url":null,"abstract":"Potato, Solatium tuberosum, is the fourth-ranked food crop used to support a growing world population because of cultivar versatility and high complex carbohydrate content. Potatoes can be stored for long periods for table and processing markets, but are plagued by storage disease problems. Diseases both in the field and during storage can be limiting factors in sustainable and profitable potato production wherever they are grown. In North America, many diseases caused by fungi are important and require a variety of management practices to reduce them to tolerable economic levels. Such diseases include late blight [Phytophthora infestans], silver scurf [Helminthosporium solani], pink rot [Phytophthora erythroseptica], dry rot [Fusarium sambucinum], verticillium wilt [Verticillium dahliae and Verticillium albo-atrum], black scurf [Rhizoctonia solani], and early blight [Alternaria solani]. These diseases have both a field and storage component, and disease management inputs may be necessary throughout the s...","PeriodicalId":9607,"journal":{"name":"Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1999-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83685638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}