Search

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Seasonal and diurnal patterns of spore dispersal by Leptosphaeria maculans, which causes blackleg disease of canola, were studied in two consecutive field seasons using a 7-day Burkard spore sampler and rotorod impaction spore samplers. Ascospores of L. maculans were trapped from mid-June to the end of July, whereas pycnidiospores were trapped from mid-July until the end of July or early August. Ascospores and pycnidiospores were trapped between 9:00 P.M. and 4:00 A,M., when air temperatures were 13 to 18°C and relative humidity was >80%. Peak ascospore and pycnidiospore dispersal was associated with rain events. Peak ascospore dispersal was found to occur several hours after rainfall ≥=2 mm, and ascospore dispersal continued for approximately 3 days after such events. Peak pycnidiospore dispersal occurred during the same hours as rain events. More ascospores and pycnidiospores were carried in the direction of prevailing winds than in other directions. To the south of the inoculated area, the gradients of disease incidence and stem disease severity were -19.2 and -0.8 m-1, respectively. Disease incidence and stem severity declined by 50% 12.5 and 5.5 m from the inoculated area, respectively. To the north of the inoculated area, the gradients of disease incidence and stem severity were -21.5 and -0.7 m-1, respectively. Disease incidence and stem severity declined by 50% 14.0 and 5.2 m from the inoculated area, respectively. In 2001, ascospores and pycnidiospores were trapped within 25 m of the inoculated area, whereas pycnidiospores were trapped up to 45 m from the inoculated area. [ABSTRACT FROM AUTHOR]

Bacillus subtilis (BSCBE4), Pseudomonas chlororaphis (PA23), endophytic P. fluorescens (ENPF1) inhibited the mycelial growth of stem blight pathogen Corynespora casiicola (Berk and Curt)Wei under in vitro . All these bacterial isolates produced both hydroxamate and carboxylate type of siderophores. But the siderophore production was maximum with the isolate ENPF1. Delivering of talc based formulation of BSCBE4 through seedling dip and foliar application effectively reduced stem blight disease incidence and increased the dry matter production under pot culture and field conditions. Application of BSCBE4, PA23 and ENPF1 increased the defense related enzymes such as peroxidase, polyphenol oxidase, chitinase and β-1,3 glucanase in P. amarus up to ten days after challenge inoculation with C. cassicola . Native gel electrophoretic analysis revealed that challenge inoculation of pathogen with BSCBE4 and PA23 induced both peroxidase and polyphnol oxidase isoforms. [ABSTRACT FROM AUTHOR]

Evaluates a dynamic disease-forecasting model used to optimize the effectiveness and minimize the use of fungicides in the control of Entomosporium mespili on Amelanchier alnifolia. Correlationbetween predicted disease pressure and disease symptom development; Control guidelines for the use of fungicides.

Relates the percent of Amelanchier alnifolia, commonly known as saskatoon leaf area infected to the relative concentration of Entomosporium mespili conidia released from the infected tissue and the development of a regression equation for the relationship. Identification when the E.mespili conidia are released in relation to prevailing environmental conditions during the growing season; Determination whether the amount of conidia released is related to the amount of rainfall during precipitation events.

Fifty-eight isolates of Mycosphaerella pinodes, collected from western Canada, New Zealand, France, Australia, the United Kingdom, and Ireland, were analyzed for pathogenic and genetic variation according to their virulence on six differential cultivars of field pea (AC Tamor, Bohatyre, Danto, Majoret, Miko, and Radley) and amplified fragment length polymorphism markers. The 56 isolates were classified into 15 pathotypes. Pathotype 1 consisted of 31 isolates that were virulent on all six pea differential cultivars. Pathotypes 14 and 15 consisted of eight isolates that were avirulent on all six differential cultivars or virulent on one of six differential cultivars. The analysis of molecular variance showed that 57.2% of the total variation was caused by differences among populations, and 42.8% was due to molecular diversity within populations. Phylogenetic analysis of molecular variation of isolates showed that most of the Canadian isolates and four Australian isolates formed two clustered groups, respectively, regardless of virulence on the six differential cultivars. Isolates from New Zealand were geographically clustered into two groups. However, the isolates from France, Ireland, and the United Kingdom were clustered with the Canadian isolates. [ABSTRACT FROM AUTHOR]

Reports on the isolation of 43 bacteria from the phylloplane and rhizosphere of potato and canola plants and testing for their ability to control the pathogen Phytophthora infestans causing late blight on potato. Bacteria with biocontrol activity; Characterization of mechanisms of inhibition including those occurring directly or indirectly through the induction of plant defense systems.

Discusses the abstract of the research paper 'First Report on the Presence of Leptosphaeria maculans Pathogenicity Group-3, the Causal Agent of Blackleg of Canola in Manitoba,' by W.G.D. Fernando and Y. Chen, and published in the October 2003 issue of 'Plant Disease.'