title: Effect of timing of application Pseudomonas fluorescens in suppression Sclerotinia sclerotiorum, the causal agent of white mold in canola.
abstract: Biological control of sclerotinia disease, as an important alternative to chemical control, has received considerable attention due to the lack of resistant varieties in most crop, and increasing concerns over fungicide resistance in population of Sclerotinia sclerotiorum, and fungicide residues in the environment. One biocontrol agent, Pseudomonas fluorescens PB-3, has been showed the antagonistic relationship between itself and S. sclerotiorum was investigated in this study. A petal infection technique was used to detect efficacy of timing of application strain PB-3 in the suppression of S. sclerotiorum on canola. Significant difference in disease severity (p<0.05) were found with respect to timing of ascospore applications in the control treatments (ascospores only). The superior competitive ability strain PB-3 was demonstrated by its complete suppression of disease severity when applied as a co-inoculation treatment or prior to ascospores inoculation. Analysis of effect of applying strain PB-3 after ascospores was indicated that treatment in which strain PB-3 was added to petals 48 or 24 h after ascospores, or when there were no bacteria present at all, had higher rates of disease progression. It would be appear that bacteria are able to significantly inhibit disease when applied before or even at the same time as ascospores. In a practical sense, this could mean that a field application of antagonist could be concurrent with infection by the pathogen.
authors.affiliation: Department of Plant Protection, University of Tehran, Karaj, Iran.
authors.forename: M
authors.initials: M
authors.lastname: Ahmadzadeh
authors.forename: S
authors.initials: S
authors.lastname: Behnam
authors.forename: A
authors.initials: A
authors.lastname: Sharifi Tehrani
authors.forename: Gh A
authors.initials: GA
authors.lastname: Hedjaroude
mesh_terms: D000898:Antibiosis; D001203:Ascomycota / Q000254:growth & development*; D001937:Brassica / Q000382:microbiology*; D015169:Colony Count, Microbial; D010572:Pest Control, Biological / Q000379:methods; D010935:Plant Diseases / Q000382:microbiology*; D011551:Pseudomonas fluorescens / Q000502:physiology*; D013172:Spores, Fungal; D013997:Time Factors