Rhizoctonia Patch of Cereals
Rhizoctonia solani AG-8
Rhizoctonia is derived from the genus name of the disease.
Rhizoctonia forms patches in cereal crops that are often circular, up to several metres across, and contain stunted plants. The roots of these plants are much shorter than those of healthy plants of the same age. The roots are often pointed or spear shaped at their ends where the disease has rotted them off.
Species Affected:Most species are affected. Barley>Wheat>Oats.
Biology:Favoured by wet warm soils.
It is a common soil pathogen that may survive on crop stubble or as sclerotia for long periods.
Spread by movement of infected soil or crop residues.
Cool climate grasses appear to be more susceptible than warmer climate grasses.
Life Cycle:Origin and History:
Circular patches in the crop containing stunted plants.
Significance:Rhizoctonia causes major yield losses in many crops.
Barley if more affected than Wheat which is more affected than Oats.
It costs the Australian wheat industry A$59 million in 2009 (Murray and Brennan, 2009) and the WA industry $27 million (Hills, 2017).
Management and Control:Do a PreDicta B soil test which is available from SARDI Root Disease Testing Service.
Cultivate soil deeper than the planting depth. Avoid zero tillage in affected areas.
Deep rip if necessary to remove compaction layers.
Use adequate fertilizer to reduce effects of the disease.
Avoid the use of sulfonylurea herbicides such as chlorsulfuron and metsulfuron.
Control all weeds before planting.
Don't burn stubble more than one year in three.
Lemon grass extracts reduce the disease (Valarini et al., 1996).
Related and Similar Species:References:
Collated by HerbiGuide. Phone 08 98444064 or www.HerbiGuide.com.au for more information.