Impacts of applied Sclerotinia sclerotiorum on the dynamics of a Cirsium arvense population

• Published in: Weed research Vol. 46; no. 1; pp. 61 - 72
• Main Authors: Bourdot, G.W, Hurrell, G.A, Saville, D.J, Leathwick, D.M
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-02-2006; Blackwell Science
• Subjects: application parameters; Arvenses; bio-herbicide; Biological and medical sciences; biological control; biological control agents; Biological control and other methods; Californian thistle; Canada thistle; Cirsium arvense; creeping thistle; disease incidence; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; growth retardation; long term effects; mycoherbicide; mycoherbicides; Parasitic plants. Weeds; pastures; Phytopathology. Animal pests. Plant and forest protection; plant damage; plant growth; population dynamics; Sclerotinia sclerotiorum; weed control; Weeds; New Zealand; Dynamic characteristic; Weed; Plant pathogen; Canada thistle; Sclerotinia sclerotiorum; creeping thistle; Compositae; bio-herbicide; Microbial herbicide; mycoherbicide; Fungi; Californian thistle; Dicotyledones; Weed science; Bioherbicide; Angiospermae; Population; Ascomycetes; Spermatophyta; Biopesticide; Cirsium arvense; Thallophyta
• ISSN: 0043-1737; 1365-3180
• DOI: 10.1111/j.1365-3180.2006.00481.x

Summary
A field experiment was conducted from October 1992 to March 1997 in a sheep‐grazed pasture in Canterbury, New Zealand, to determine the effects of the fungus Sclerotinia sclerotiorum on the long‐term dynamics of a population of Cirsium arvense. The pathogen was applied in mid‐spring either once or in three consecutive years when the C. arvense shoots were vegetative rosettes, using a granular, mycelium‐on‐wheat preparation that lodged on the C. arvense leaves, stems and in the leaf axils. The single application caused disease in the C. arvense that was confined to the application year. The disease resulted in a temporary (17 months) reduction in population size through initial mortalities among treated shoots and resultant reductions in root growth, adventitious root bud, subterranean shoot and, subsequently, aerial shoot population sizes. The soil seedbank was 80% lower in the treated plots than in the control plots in the first year. Seedlings were never found. The annually repeated application of S. sclerotiorum did not result in the expected continuing decline in the C. arvense population relative to the control population.