White rust/staghead

Constraint - White rust/staghead

Description

• White rust is caused by the fungus Albugo candida

• The disease is uncommon on B. napus (Australian canola varieties) but does infect B. juncea (juncea canola / Indian mustard) 

Symptoms

• White to cream coloured pustules form on the underside of leaves and on floral parts which rupture the host epidermis exposing a white chalky dust

• On the upper surface of the leaves, the infected areas are bleached and thickened

• Infections of the growing tips and flower heads give rise to stagheads 

• Stagheads are swollen, twisted and distorted flower heads that produce little to no seed and become brown and hard as they mature

Damage

• If uncontrolled, yield penalty can occur

Management

Obtaining clean seed from disease free or low disease crops, as well as controlling cruciferous weeds, and implementing extended rotations will all reduce the risk of infection. If warranted consider growing B. napus rather than B. juncea.

Links and Resources

DEPI VIC - Canola diseases. White rust The section on white rust/staghead contains information on introduction, symptoms, disease cycle, and management. Published 2008, page last updated 2009, reviewed 2010.

DEPI VIC - Identification and management of field crop diseases in Victoria. White rust/staghead Page 146 Table 11.1 gives a key for canola diseases at different stages of plant growth. Page 156 contains information on introduction, symptoms, disease cycle, and management. Published 2012.

GRDC - Best Practice Management Guide. White rust Page 65. Introduction, symptoms, disease cycle, and management. Page 59. Table of common disease of canola. Published 2009.