Brown discolouration of the base of tillers and crowns and occasional dark streaking up the lower sheaths. White fungal thread masses between the tillers and on the leaf sheaths and stems near the crown near ground level or just below. Plant may die at tillering or form white heads at harvest. 1-2 mm round white to brown sclerotia form near the base of the plant as it dies at the end of the season.
Broadleaved Plants
White, cottony fungal threads surround the base of the plant and adjacent soil and produce resting spore bodies or sclerotia that are initially white but soon turn to brown and are about 2 mm diameter balls. Plant may wither and die quickly
Species Affected:
Cereals.
Sorghum is susceptible.
A wide range of broadleaved plants and vegetables
Beetroot, Carnation, Dahlia, Iris and Rhubarb are susceptible.
Biology:
Favoured by soils with high organic matter and temperatures from 25-300C.
Alternating wetting and drying of the soil encourage sclerotia to germinate.
A common soil inhabitant.
Sclerotia can survive in the soil for many years.
Burial to more than 150 mm deep in moist soil will kill sclerotia in 6 weeks.
Life Cycle:
Origin and History:
Distribution:
More common in the warmer cereal growing areas.
Significance:
Control is rarely economic.
Management and Control:
Avoid planting cereals into warm soils.
Avoid planting after summer crops such as Sorghum.
Remove and destroy infected plants.
Avoid burying foliage when cultivating around plants.
Don't compost infected plants.
Avoid irrigation regimes that result in alternate wetting and drying of soil.
Use healthy planting material for vegetatively propagated crops e.g. Rhubarb crowns.
Quintozene can be used as a soil drench in high value situations.
Related and Similar Species:
Looks similar to Crown Rot but often has dark brown streaking of the lower sheaths and is more common in wetter warmer areas.
References:
1208
1205
1210
Acknowledgments:
Collated by HerbiGuide. Phone 08 98444064 for more information.