European Journal of Plant Pathology (2010) 126, 13-27

T. Yli-Mattila, G. Kalko, A. Hannukkala, S. Paavanen-Huhtala and K. Hakala (2010)
Prevalence, species composition, genetic variation and pathogenicity of clover rot (Sclerotinia trifoliorum) and Fusarium spp. in red clover in Finland
European Journal of Plant Pathology 126 (1), 13-27
Abstract: The species composition of a total of 173 red clover root fungal isolates from red clover roots from two established organic fields, a field in a transitional phase to organic and from two conventional fields was investigated based on morphology and molecular methods. Fusarium avenaceum was the most common Fusarium species overall but it occurrred less frequently in older organic fields. Gliocladium spp., Trichoderma spp. and Rhizoctonia spp. isolates were more common in the established organic clover fields, which had been under organic management for more than ten years and in one conventional field, than in a field still in the transitional phase. The taxonomical status of certain Fusarium, Alternaria and Sclerotinia isolates difficult to identify by morphological traits alone could be confirmed by species-specific primers and by comparing their ITS (internal transcribed spacer region) sequences to known sequences. The fingerprinting patterns of RAPD-PCR products could be used for the identification of fungal isolates and for studying the genetic variation among the isolates. Only one of the Fusarium isolates originating from apparently healthy red clover roots was clearly pathogenic to germinated red clover seedlings. In detached leaf experiments, the cvs Jokioinen and Ilte were more susceptible to one of the Sclerotinia trifoliorum isolates than cvs Betty and Bjursele, while all of them were equally susceptible to two other S. trifoliorum isolates. In further greenhouse experiments with intact plants it was possible to slow down the development of clover rot to some extent by means of one of the biological agents tested (Bacillus subtilis 10-VIZR, commercial name Alirin B), and almost completely by chemical control.
(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): Asko O. Hannukkala, Sari Paavanen-Huhtala

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution
control - general
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Sclerotinia trifoliorum	Clover (Trifolium)	Finland
	Fusarium avenaceum	Clover (Trifolium)	Finland
Bacillus subtilis (antagonist)	Sclerotinia trifoliorum