Showing 2 results for Bacterial Blight
S. M. Taghavi, K. Keshavarz,
Volume 6, Issue 4 (1-2003)
Abstract
During the period from 1997 to 1998, samples of wheat leaves were collected from different wheat farms in Fars and Kohgiluyeh & Boyrahmad provinces to identify the causal agent of wheat leaf blight. On the basis of LOPAT tests and production of fluorescent pigment on KB medium, 181 bacterial isolates were recovered from the samples. Based on biochemical, physiological and pathogenicity tests, the isolates were categorized in five groups. One group was found to be Pseudomonas fluorescens (Pf) and the remaining groups were identified as P. syringae pv. syringae (Pss). The pathogenicity test indicated that Pss strains were the causal agent of bacterial wheat leaf blight in Fars and Kohgiluyeh & Boyrahmad provinces. Whole protein electrophoretic patterns were similar in Pss isolates but only a few showed small variation in some subordinated bands. Pathogenic strains of Pss were also isolated from annual and perennial weeds such as foxtail, hairy vetch, oat grass, barley grass and Cynodon dactylon in some areas including Saadat Shahr and Marvdasht. Among the wheat cultivars tested, Tajan was susceptible to the pathogen but others were immune, resistant, moderately resistant, or moderately susceptible. The results showed that Pss is a seed-born pathogen in wheat kernel perhaps as endophyte in the seeds.
A Akhavan, M Bahar, Gh Saeedi, M Lak,
Volume 13, Issue 47 (4-2009)
Abstract
To understand the role of relative humidity rate, host genotype, inoculation method and growth stage in epidemiology of bean common blight, two greenhouse experiments were carried out monitoring epiphytic population size of Xanthomonas axonopodis pv. phaseoli (Xap) and disease severity. The result showed significant differences among genotypes, inoculation methods and growth stages for epiphytic population size and sam effects except genotypes for disease severity. The epiphytic population size was significantly higher on spray inoculated Khomein cultivar of bean during flowering (R6). However, the relative humidity rates did not significantly affect population dynamics of epiphytic Xap and the disease severity. Two field experiments were also carried out to determine the effects of irrigation systems (furrow irrigation and overhead sprinkler irrigation), inoculation method, growth stage and their interactions on epiphytic population size of Xap and disease severity. The result showed that the epiphytic population size and disease severity were higher on spray inoculated plants irrigated with overhead sprinkler system during pods filling (R8). In this study, a significant positive correlation was found between epiphytic population size of Xap and bean common bacterial blight severity.
