Biocontrol Science and Technology (1999) 9, 365-377

L.J. Cornwallis, A. Stewart, G.W. Bourdot, R.E. Gaunt, I.C. Harvey and D.J. Saville (1999)
Pathogenicity of Sclerotinia sclerotiorum on Ranunculus acris in dairy pasture
Biocontrol Science and Technology 9 (3), 365-377
Abstract: Fifty-four isolates of Sclerotinia sclerotiorum from Ranunculus acris and other natural hosts were applied as mycelial infested kibbled wheat onto 6 month-old R. acris plants in two glasshouse screening experiments. Most isolates (90%) did not differ in their pathogenicity towards R. acris. One isolate, S. sclerotiorum G45, was selected based on its ability to cause severe disease and suppress regeneration of R. acris. A field experiment was conducted to determine the efficacy of S. sclerotiorum (G45) against R. acris in infested dairy pastures in the Takaka Valley, Golden Bay, New Zealand. Isolate G45 was formulated as a wettable powder and was applied as a slurry at 20 and 40 ml/plant in December 1995. After 10 weeks, regeneration from the crown of treated plants was apparent and a second application of S. sclerotiorum was made in February 1996. Best control of R. acris was obtained when the plants were inoculated in full flower in December. At the first time of treatment, the 40 ml application of S. sclerotiorum slurry reduced the total dry weight of R. acris by an average of 57%. The second application had no effect on total dry weight, possibly because moisture levels were not sufficient for S. sclerotiorum infection. This study confirmed S. sclerotiorum to be an aggressive pathogen of R. acris under both glasshouse and field conditions. As a result, this pathogen has potential as a mycoherbicide for R. acris. Further experiments are required to explore ways of enhancing the efficacy of S. sclerotiorum against R. acris by manipulation of the host, pathogen and environment.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Graeme Wayne Bourdot

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
application technology
evaluation - screening - selection

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Ranunculus acris (weed)		New Zealand
Sclerotinia sclerotiorum (weed pathogen)	Ranunculus acris (weed)	Grasses/turf/rangeland	New Zealand