Lucerne Sclerotinia Root Rot
Lucerne Sclerotinia Crown Rot
Description:White, cottony, dense fungal growth on heads and stems. sometimes with tiny black spore bodies (sclerotia). Underlying plant tissue is soft and wet.
Sclerotia of Sclerotinia minor are 1-2 mm long, oval to spherical and often clumped together.
Sclerotia of Sclerotinia sclerotiorum are 5-10 mm long, irregular shape and look like rat faeces.
Species Affected:Brassicas, Canola, Lucerne.
Brussels Sprouts and Cabbages are very susceptible.
Biology:Favoured by cool, wet conditions and cultivation. Tolerates a wide temperature range.
Most common in autumn and spring on moist soils.
Tends to initially attack old or decaying leaves and tissue.
Sclerotia can survive for many years in the soil.
Often builds up on susceptible hosts such as legumes, Capeweed, Lettuce and Potato.
Spread by movement of soil containing spores.
Sclerotinia sclerotiotum can produce wind dispersed spores.
Life Cycle:Origin and History:
Occurs on Lucerne pastures in the north and central agricultural regions of WA as both a root rot and a crown rot.
Significance:Very damaging to Brussels Sprouts and Cabbage heads.
Management and Control:Deep cultivation to bury sclerotia laden soil.
Rotation with resistant cereal or grass crops helps reduce the severity of the infection.
Lemon grass extracts reduce the pathogenicity of some species (Valarini et al., 1996)).
Related and Similar Species:References:
(Donald et al., 2002)
Farming Ahead, February 2017, p48.
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