Articles
RHIZOCTONIA SOLANI AG 8 ASSOCIATED WITH STUNTED ONION PATCHES IN SOUTH AUSTRALIA
Article number
969_33
Pages
247 – 253
Language
English
Abstract
Patches of stunted onion plants associated with Rhizoctonia solani AG8 are wide spread in commercial onion plantings grown in the sandy calcareous soils of the Mallee region of South Australia.
Patches vary in size from 1 to 25 m or more in diameter with a distinct delineation between stunted and adjacent normal plants.
Seedling height within stunted patches is 30 to 75% less than that of adjacent non-stunted shoot areas and mature bulb size reduced by a mean 28%. Analysis of
R. solani AG8 in the soil profile showed that inoculum sufficient to cause disease was located in the top 15 cm.
Development of onion stunt and growth of R. solani AG8 was higher in soil with reduced organic C and microbial activity.
The development of disease and growth of pathogen in the soil was reduced at 20°C in comparison to 15°C. While the symptoms of disease were greater at 25% water holding capacity (WHC) compared to 55% WHC there was no difference in pathogen growth at these two soil moisture contents suggesting that improving conditions for plant growth reduced the symptoms of onion stunt.
The fraction of coarse sand (2-0.2 mm) present in the soil favoured development of disease symptoms and growth.
Patches vary in size from 1 to 25 m or more in diameter with a distinct delineation between stunted and adjacent normal plants.
Seedling height within stunted patches is 30 to 75% less than that of adjacent non-stunted shoot areas and mature bulb size reduced by a mean 28%. Analysis of
R. solani AG8 in the soil profile showed that inoculum sufficient to cause disease was located in the top 15 cm.
Development of onion stunt and growth of R. solani AG8 was higher in soil with reduced organic C and microbial activity.
The development of disease and growth of pathogen in the soil was reduced at 20°C in comparison to 15°C. While the symptoms of disease were greater at 25% water holding capacity (WHC) compared to 55% WHC there was no difference in pathogen growth at these two soil moisture contents suggesting that improving conditions for plant growth reduced the symptoms of onion stunt.
The fraction of coarse sand (2-0.2 mm) present in the soil favoured development of disease symptoms and growth.
Publication
Authors
S.T. Anstis, T.J. Wicks, S. Pederick
Keywords
Allium cepa, soilborne disease
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