Damping off

Constraint - Damping off 

Description

• Damping-off is usually caused by the fungus Rhizoctonia solani

• Damage is caused when conditions are not ideal for early seedling growth

• Damping-off fungi are soil-borne and survive in the soil in resistant structures when no host is present

Symptoms

• Symptoms occur in patches that can spread quickly during cold wet conditions

• Plants fail to emerge (pre-emergence rot)

• Plants emerge and collapse at ground level (post-emergence damping-off), with discoloured leaves and sometimes a shrivelled tap root 

• Surviving plants are normally stunted and may flower and mature prematurely

Damage

• Yield loss is unusual unless plant numbers are severely reduced 

• If seedling loss is uniform through the crop, the surviving plants will often compensate

• If seedling loss is patchy and very severe, areas may have to be resown

• Once past the seedling stage canola plants are not adversely affected by damping-off

Management

Soil tillage after the autumn break will control the various fungi species by destroying thier filaments in the soil. Application of a seed fungicide treatment at sowing can also reduce damping-off damage.

Links and Resources

DAFWA - Diagnosing damping off in canola Introduction, what to look for in paddock and plant, what else it could be, where does it come from, and management strategies. Page last updated 2014.

DEPI VIC - Canola diseases. Damping off The section on damping off contains information on introduction, symptoms, disease cycle, and management. Published 2008, updated 2009, reviewed 2010.

DEPI VIC - Identification and management of field crop diseases in Victoria. Damping off Page 146. Table 11.1 gives a key for canola diseases at different stages of plant growth. Page 152 contains introduction, symptoms, disease cycle, and management. Published 2012.

GRDC - Best Practice Management Guide. Damping off Page 64. Introduction, symptoms, disease cycle, and management.  Page 59 table of common disease of canola. Published 2009.

Victorian winter crop summary 2014 - Damping off Page 45. Table 1: canola disease guide summary. Description of organism, symptoms, occurrence, inoculum source, and control. Updated annually.