Managing Blackleg and Sclerotinia in Canola

Using
this
Guide
This guide will help you identify
and manage blackleg and sclerotinia
the two most damaging diseases to
canola crops across Australia.
For identification of other canola
diseases refer to the “Canola
Diseases Back Pocket Guide” or
“Canola: The Ute Guide”.
Blackleg
Spread of the disease
Number of blackleg spores
Number of airborne spores landing on the ground
in relation to the distance from canola residues
0
300
500
1000
Blackleg is the most common and serious disease of
canola in Australia.
Autumn rains bring a massive release of spores from
infected stubbles above the soil surface. The more stubble
and the closer it is to emerging canola crops the greater
the risk of severe infection. Blackleg spores are carried by
winds to nearby seedling crops. Most spores travel less
than 300 m, but some can travel several kilometres. In
general stubble less than 12 months old releases over 99%
of all blackleg spores, older stubble accounts for very few
spores. However, in some cases significant spore release
can occur from two year old stubbles.
2000
Distance (metres)
courtesy Department of Agriculture, WA
Photo Department of Agriculture, WA
Seedling
infected with
Blackleg
Infection
Grey, circular spots (lesions) with black specks (fruiting
bodies) form on the cotyledons and leaves. Lesions can
appear on any part of the plant and even occur on
resistant varieties.
Blackleg grows from the lesion down within the stem to
the crown where it will cause a constriction in the stem
just below the first leaves . It can be confused with
“damping off”, but is distinguished by a characteristic
thinning of the stem immediately below the cotyledons.
Photo Department of Agriculture, WA
Heavy infection soon after germination can kill seedlings
and rosette size plants. Plants will continue to die right
through the growing season, causing older plants to
lodge. Partial constriction of the stem will reduce seed
size and oil percentage.
Leaf lesions
Cool showery weather in autumn and winter favours
infection and spread of the disease.
High Risk Areas
Include the combination of:
• High rainfall districts with greater than 400 mm
annual rainfall.
• And districts which had a HIGH percentage of
paddocks producing canola during the previous season.
Photo Department of Agriculture, WA
Recommendation:
Only sow varieties with Canola Association of Australia
Blackleg resistant rating of 6 or more (Resistant and
highly resistant). Resistant rating is 9 (highly resistant)
to 1 (susceptible).The latest blackleg resistance rating
brochures are available from seed merchants and
Department of Agriculture offices. In WA, growers
should refer to the latest WA blackleg resistance ratings
on canola varieties farmnote.
Severe crown canker
Any recommendations contained in this
publication do not necessarily represent
GRDC policy. No person should act on the
basis of the contents of this publication,
whether as to matters of fact or opinion or
other content, without first obtaining
specific, independent professional advice
which confirms the information contained
in this publication.
Keep this year’s crop as far as possible from last year’s
stubble.
The “Managing Blackleg and Sclerotinia in Canola”
Back Pocket Guide is part of a series of Back Pocket
Guides published by GRDC.
For free copies please contact:
GRDC Publications Manager
PO Box E6 Kingston, ACT 2604
Telephone: 02 6272 5525
Facsimile: 02 6271 6430
Email:
[email protected]
GRDC
Grains
Research &
Development
Corporation
POCKET GUIDE
Managing Blackleg and
Sclerotinia in Canola: THE BACK
Using
this
Guide
This guide will help you identify
and manage blackleg and sclerotinia
the two most damaging diseases to
canola crops across Australia.
For identification of other canola
diseases refer to the “Canola
Diseases Back Pocket Guide” or
“Canola: The Ute Guide”.
Blackleg
Spread of the disease
Number of blackleg spores
Number of airborne spores landing on the ground
in relation to the distance from canola residues
0
300
500
1000
Blackleg is the most common and serious disease of
canola in Australia.
Autumn rains bring a massive release of spores from
infected stubbles above the soil surface. The more stubble
and the closer it is to emerging canola crops the greater
the risk of severe infection. Blackleg spores are carried by
winds to nearby seedling crops. Most spores travel less
than 300 m, but some can travel several kilometres. In
general stubble less than 12 months old releases over 99%
of all blackleg spores, older stubble accounts for very few
spores. However, in some cases significant spore release
can occur from two year old stubbles.
2000
Distance (metres)
courtesy Department of Agriculture, WA
Photo Department of Agriculture, WA
Seedling
infected with
Blackleg
Infection
Grey, circular spots (lesions) with black specks (fruiting
bodies) form on the cotyledons and leaves. Lesions can
appear on any part of the plant and even occur on
resistant varieties.
Blackleg grows from the lesion down within the stem to
the crown where it will cause a constriction in the stem
just below the first leaves . It can be confused with
“damping off”, but is distinguished by a characteristic
thinning of the stem immediately below the cotyledons.
Photo Department of Agriculture, WA
Heavy infection soon after germination can kill seedlings
and rosette size plants. Plants will continue to die right
through the growing season, causing older plants to
lodge. Partial constriction of the stem will reduce seed
size and oil percentage.
Leaf lesions
Cool showery weather in autumn and winter favours
infection and spread of the disease.
High Risk Areas
Include the combination of:
• High rainfall districts with greater than 400 mm
annual rainfall.
• And districts which had a HIGH percentage of
paddocks producing canola during the previous season.
Photo Department of Agriculture, WA
Recommendation:
Only sow varieties with Canola Association of Australia
Blackleg resistant rating of 6 or more (Resistant and
highly resistant). Resistant rating is 9 (highly resistant)
to 1 (susceptible).The latest blackleg resistance rating
brochures are available from seed merchants and
Department of Agriculture offices. In WA, growers
should refer to the latest WA blackleg resistance ratings
on canola varieties farmnote.
Severe crown canker
Any recommendations contained in this
publication do not necessarily represent
GRDC policy. No person should act on the
basis of the contents of this publication,
whether as to matters of fact or opinion or
other content, without first obtaining
specific, independent professional advice
which confirms the information contained
in this publication.
Keep this year’s crop as far as possible from last year’s
stubble.
The “Managing Blackleg and Sclerotinia in Canola”
Back Pocket Guide is part of a series of Back Pocket
Guides published by GRDC.
For free copies please contact:
GRDC Publications Manager
PO Box E6 Kingston, ACT 2604
Telephone: 02 6272 5525
Facsimile: 02 6271 6430
Email:
[email protected]
GRDC
Grains
Research &
Development
Corporation
POCKET GUIDE
Managing Blackleg and
Sclerotinia in Canola: THE BACK
Blackleg
Lower Risk Areas
Include the combination of:
• Lower rainfall areas with less than 400 mm annual
rainfall.
Photo Department of Agriculture, WA
• And districts which had a LOW percentage of
paddocks producing canola during the previous
season.
Blackleg lesion on a canola pod
Recommendation:
Only sow varieties with Canola Association of Australia
Blackleg resistant rating of 5 or more (moderately
resistant, resistant and highly resistant). In WA, growers
should refer to the latest WA blackleg resistance ratings
on canola varieties farmnote. In districts where there is
very little stubble residue, and paddocks are well isolated
from residues, varieties with a rating of 4 may be grown.
Managing the Risk of Blackleg
Rainfall is only a guide to the likely risk of blackleg
and some properties could be in a higher risk category,
due to the high intensity with which canola has been
grown in the district over the last year.
Spores on canola stubble
Minimise the risk of crop damage due to blackleg by:
• Choosing a variety with the highest level of disease
resistance which is adapted to your rainfall district.
• Maximising the distance between last year’s canola
stubble and this years crop; upwind is better.
• Reduce the amount of canola residue by grazing,
burying or burning etc.
Stem canker can cause plants to lodge
Sclerotinia
Stem Rot
White fluffy growth of Sclerotinia
on canola stem
The application of systemic fungicides may be a useful
tool for blackleg management. However, the profitability
of this needs to be considered.
Individual plants or
patches die
Sclerotinia stem rot appears as white fluffy growth
usually just above the soil level on the stem, however
infection can occur 30 to 45 centimetres above the soil
surface. Crop growth stops above this point and plants
wilt and ripen prematurely. Severely affected plants
will die and lodge. Affected area on the plant is usually
greyish white or brownish white.
The disease is widespread in canola growing areas,
but generally only severe in NSW and NE Victoria.
It is favoured by warm damp weather during flowering.
In most canola growing regions in Australia the
climatic conditions are not favourable for Sclerotinia.
Black, irregular-shaped fungal fruiting bodies (sclerotia)
form inside infected stems, and in moist weather
conditions they can also form on the outside of the
affected area. Infections high on the stems can result
in contamination of the seed.
Sclerotinia can survive as sclerotia in the soil for up to
8 years. The fungus probably also survives in the soil
by colonising the roots of other plant species such as
capeweed, lupins and peas.
Black fungal fruiting bodies (sclerotia)
inside infected stems
Control
• Currently there are no control recommendations
for Australia.
• In Canada the only control is to spray fungicides
during flowering, although this is likely to work in
Australia it may prove too costly due to our extended
flowering time and consequently multiple sprays
required (no fungicides are registered). If considering
using fungicides check withholding periods.
• Cultural methods for reducing the amount of
inoculum include:
– Use cereals in the rotation as grasses are not
affected by sclerotinia (all broad leaf crops are
susceptible).
– Sow canola seed that is free of sclerotinia
contamination (sclerotia).
– Reduce stubble residues.
– If you have a sclerotinia problem this season you
will not necessarily have a problem next season
as the disease is dependant on specific weather
conditions during the flowering period.
Graph and photos courtesy
“Beating Blackleg in WA” Bulletin,
Martin Barbetti, Ravjit Khangura,
Moin Salam, Paul Carmody, Mark
Sweetingham, Graham Walton and
Christine Zaicou-Kunesh; Department
of Agriculture, WA
Guide concept: Ross Andrews, GRDC
Photography: Stephen Marcroft, Mark
Stanley, Ravijit Khangura, Martin
Barbetti
Text: Stephen Marcroft, Trent Potter,
Paul Parker, Ravjit Khangura
This guide should be used in association with the
following publications:
• Canola: The Ute Guide
• Your Guide to Growing Golden Canola, Department
of Agriculture, WA
• ‘Managing Blackleg-a growers guide to making the
right decisions in managing blackleg disease of canola
in Western Australia’, Department of Agriculture,
WA, Bulletin 4480
• Canola, NSW Agriculture
• Canola Check Tool Kit, Primary Industries and
Resources SA.
• Canola Cache, Kondinin
Each state department of agriculture / primary industries
also have a series of farm notes / fact sheets on canola
production which are updated on a regular basis.
Blackleg
Lower Risk Areas
Include the combination of:
• Lower rainfall areas with less than 400 mm annual
rainfall.
Photo Department of Agriculture, WA
• And districts which had a LOW percentage of
paddocks producing canola during the previous
season.
Blackleg lesion on a canola pod
Recommendation:
Only sow varieties with Canola Association of Australia
Blackleg resistant rating of 5 or more (moderately
resistant, resistant and highly resistant). In WA, growers
should refer to the latest WA blackleg resistance ratings
on canola varieties farmnote. In districts where there is
very little stubble residue, and paddocks are well isolated
from residues, varieties with a rating of 4 may be grown.
Managing the Risk of Blackleg
Rainfall is only a guide to the likely risk of blackleg
and some properties could be in a higher risk category,
due to the high intensity with which canola has been
grown in the district over the last year.
Spores on canola stubble
Minimise the risk of crop damage due to blackleg by:
• Choosing a variety with the highest level of disease
resistance which is adapted to your rainfall district.
• Maximising the distance between last year’s canola
stubble and this years crop; upwind is better.
• Reduce the amount of canola residue by grazing,
burying or burning etc.
Stem canker can cause plants to lodge
Sclerotinia
Stem Rot
White fluffy growth of Sclerotinia
on canola stem
The application of systemic fungicides may be a useful
tool for blackleg management. However, the profitability
of this needs to be considered.
Individual plants or
patches die
Sclerotinia stem rot appears as white fluffy growth
usually just above the soil level on the stem, however
infection can occur 30 to 45 centimetres above the soil
surface. Crop growth stops above this point and plants
wilt and ripen prematurely. Severely affected plants
will die and lodge. Affected area on the plant is usually
greyish white or brownish white.
The disease is widespread in canola growing areas,
but generally only severe in NSW and NE Victoria.
It is favoured by warm damp weather during flowering.
In most canola growing regions in Australia the
climatic conditions are not favourable for Sclerotinia.
Black, irregular-shaped fungal fruiting bodies (sclerotia)
form inside infected stems, and in moist weather
conditions they can also form on the outside of the
affected area. Infections high on the stems can result
in contamination of the seed.
Sclerotinia can survive as sclerotia in the soil for up to
8 years. The fungus probably also survives in the soil
by colonising the roots of other plant species such as
capeweed, lupins and peas.
Black fungal fruiting bodies (sclerotia)
inside infected stems
Control
• Currently there are no control recommendations
for Australia.
• In Canada the only control is to spray fungicides
during flowering, although this is likely to work in
Australia it may prove too costly due to our extended
flowering time and consequently multiple sprays
required (no fungicides are registered). If considering
using fungicides check withholding periods.
• Cultural methods for reducing the amount of
inoculum include:
– Use cereals in the rotation as grasses are not
affected by sclerotinia (all broad leaf crops are
susceptible).
– Sow canola seed that is free of sclerotinia
contamination (sclerotia).
– Reduce stubble residues.
– If you have a sclerotinia problem this season you
will not necessarily have a problem next season
as the disease is dependant on specific weather
conditions during the flowering period.
Graph and photos courtesy
“Beating Blackleg in WA” Bulletin,
Martin Barbetti, Ravjit Khangura,
Moin Salam, Paul Carmody, Mark
Sweetingham, Graham Walton and
Christine Zaicou-Kunesh; Department
of Agriculture, WA
Guide concept: Ross Andrews, GRDC
Photography: Stephen Marcroft, Mark
Stanley, Ravijit Khangura, Martin
Barbetti
Text: Stephen Marcroft, Trent Potter,
Paul Parker, Ravjit Khangura
This guide should be used in association with the
following publications:
• Canola: The Ute Guide
• Your Guide to Growing Golden Canola, Department
of Agriculture, WA
• ‘Managing Blackleg-a growers guide to making the
right decisions in managing blackleg disease of canola
in Western Australia’, Department of Agriculture,
WA, Bulletin 4480
• Canola, NSW Agriculture
• Canola Check Tool Kit, Primary Industries and
Resources SA.
• Canola Cache, Kondinin
Each state department of agriculture / primary industries
also have a series of farm notes / fact sheets on canola
production which are updated on a regular basis.
Blackleg
Lower Risk Areas
Include the combination of:
• Lower rainfall areas with less than 400 mm annual
rainfall.
Photo Department of Agriculture, WA
• And districts which had a LOW percentage of
paddocks producing canola during the previous
season.
Blackleg lesion on a canola pod
Recommendation:
Only sow varieties with Canola Association of Australia
Blackleg resistant rating of 5 or more (moderately
resistant, resistant and highly resistant). In WA, growers
should refer to the latest WA blackleg resistance ratings
on canola varieties farmnote. In districts where there is
very little stubble residue, and paddocks are well isolated
from residues, varieties with a rating of 4 may be grown.
Managing the Risk of Blackleg
Rainfall is only a guide to the likely risk of blackleg
and some properties could be in a higher risk category,
due to the high intensity with which canola has been
grown in the district over the last year.
Spores on canola stubble
Minimise the risk of crop damage due to blackleg by:
• Choosing a variety with the highest level of disease
resistance which is adapted to your rainfall district.
• Maximising the distance between last year’s canola
stubble and this years crop; upwind is better.
• Reduce the amount of canola residue by grazing,
burying or burning etc.
Stem canker can cause plants to lodge
Sclerotinia
Stem Rot
White fluffy growth of Sclerotinia
on canola stem
The application of systemic fungicides may be a useful
tool for blackleg management. However, the profitability
of this needs to be considered.
Individual plants or
patches die
Sclerotinia stem rot appears as white fluffy growth
usually just above the soil level on the stem, however
infection can occur 30 to 45 centimetres above the soil
surface. Crop growth stops above this point and plants
wilt and ripen prematurely. Severely affected plants
will die and lodge. Affected area on the plant is usually
greyish white or brownish white.
The disease is widespread in canola growing areas,
but generally only severe in NSW and NE Victoria.
It is favoured by warm damp weather during flowering.
In most canola growing regions in Australia the
climatic conditions are not favourable for Sclerotinia.
Black, irregular-shaped fungal fruiting bodies (sclerotia)
form inside infected stems, and in moist weather
conditions they can also form on the outside of the
affected area. Infections high on the stems can result
in contamination of the seed.
Sclerotinia can survive as sclerotia in the soil for up to
8 years. The fungus probably also survives in the soil
by colonising the roots of other plant species such as
capeweed, lupins and peas.
Black fungal fruiting bodies (sclerotia)
inside infected stems
Control
• Currently there are no control recommendations
for Australia.
• In Canada the only control is to spray fungicides
during flowering, although this is likely to work in
Australia it may prove too costly due to our extended
flowering time and consequently multiple sprays
required (no fungicides are registered). If considering
using fungicides check withholding periods.
• Cultural methods for reducing the amount of
inoculum include:
– Use cereals in the rotation as grasses are not
affected by sclerotinia (all broad leaf crops are
susceptible).
– Sow canola seed that is free of sclerotinia
contamination (sclerotia).
– Reduce stubble residues.
– If you have a sclerotinia problem this season you
will not necessarily have a problem next season
as the disease is dependant on specific weather
conditions during the flowering period.
Graph and photos courtesy
“Beating Blackleg in WA” Bulletin,
Martin Barbetti, Ravjit Khangura,
Moin Salam, Paul Carmody, Mark
Sweetingham, Graham Walton and
Christine Zaicou-Kunesh; Department
of Agriculture, WA
Guide concept: Ross Andrews, GRDC
Photography: Stephen Marcroft, Mark
Stanley, Ravijit Khangura, Martin
Barbetti
Text: Stephen Marcroft, Trent Potter,
Paul Parker, Ravjit Khangura
This guide should be used in association with the
following publications:
• Canola: The Ute Guide
• Your Guide to Growing Golden Canola, Department
of Agriculture, WA
• ‘Managing Blackleg-a growers guide to making the
right decisions in managing blackleg disease of canola
in Western Australia’, Department of Agriculture,
WA, Bulletin 4480
• Canola, NSW Agriculture
• Canola Check Tool Kit, Primary Industries and
Resources SA.
• Canola Cache, Kondinin
Each state department of agriculture / primary industries
also have a series of farm notes / fact sheets on canola
production which are updated on a regular basis.
Blackleg
Lower Risk Areas
Include the combination of:
• Lower rainfall areas with less than 400 mm annual
rainfall.
Photo Department of Agriculture, WA
• And districts which had a LOW percentage of
paddocks producing canola during the previous
season.
Blackleg lesion on a canola pod
Recommendation:
Only sow varieties with Canola Association of Australia
Blackleg resistant rating of 5 or more (moderately
resistant, resistant and highly resistant). In WA, growers
should refer to the latest WA blackleg resistance ratings
on canola varieties farmnote. In districts where there is
very little stubble residue, and paddocks are well isolated
from residues, varieties with a rating of 4 may be grown.
Managing the Risk of Blackleg
Rainfall is only a guide to the likely risk of blackleg
and some properties could be in a higher risk category,
due to the high intensity with which canola has been
grown in the district over the last year.
Spores on canola stubble
Minimise the risk of crop damage due to blackleg by:
• Choosing a variety with the highest level of disease
resistance which is adapted to your rainfall district.
• Maximising the distance between last year’s canola
stubble and this years crop; upwind is better.
• Reduce the amount of canola residue by grazing,
burying or burning etc.
Stem canker can cause plants to lodge
Sclerotinia
Stem Rot
White fluffy growth of Sclerotinia
on canola stem
The application of systemic fungicides may be a useful
tool for blackleg management. However, the profitability
of this needs to be considered.
Individual plants or
patches die
Sclerotinia stem rot appears as white fluffy growth
usually just above the soil level on the stem, however
infection can occur 30 to 45 centimetres above the soil
surface. Crop growth stops above this point and plants
wilt and ripen prematurely. Severely affected plants
will die and lodge. Affected area on the plant is usually
greyish white or brownish white.
The disease is widespread in canola growing areas,
but generally only severe in NSW and NE Victoria.
It is favoured by warm damp weather during flowering.
In most canola growing regions in Australia the
climatic conditions are not favourable for Sclerotinia.
Black, irregular-shaped fungal fruiting bodies (sclerotia)
form inside infected stems, and in moist weather
conditions they can also form on the outside of the
affected area. Infections high on the stems can result
in contamination of the seed.
Sclerotinia can survive as sclerotia in the soil for up to
8 years. The fungus probably also survives in the soil
by colonising the roots of other plant species such as
capeweed, lupins and peas.
Black fungal fruiting bodies (sclerotia)
inside infected stems
Control
• Currently there are no control recommendations
for Australia.
• In Canada the only control is to spray fungicides
during flowering, although this is likely to work in
Australia it may prove too costly due to our extended
flowering time and consequently multiple sprays
required (no fungicides are registered). If considering
using fungicides check withholding periods.
• Cultural methods for reducing the amount of
inoculum include:
– Use cereals in the rotation as grasses are not
affected by sclerotinia (all broad leaf crops are
susceptible).
– Sow canola seed that is free of sclerotinia
contamination (sclerotia).
– Reduce stubble residues.
– If you have a sclerotinia problem this season you
will not necessarily have a problem next season
as the disease is dependant on specific weather
conditions during the flowering period.
Graph and photos courtesy
“Beating Blackleg in WA” Bulletin,
Martin Barbetti, Ravjit Khangura,
Moin Salam, Paul Carmody, Mark
Sweetingham, Graham Walton and
Christine Zaicou-Kunesh; Department
of Agriculture, WA
Guide concept: Ross Andrews, GRDC
Photography: Stephen Marcroft, Mark
Stanley, Ravijit Khangura, Martin
Barbetti
Text: Stephen Marcroft, Trent Potter,
Paul Parker, Ravjit Khangura
This guide should be used in association with the
following publications:
• Canola: The Ute Guide
• Your Guide to Growing Golden Canola, Department
of Agriculture, WA
• ‘Managing Blackleg-a growers guide to making the
right decisions in managing blackleg disease of canola
in Western Australia’, Department of Agriculture,
WA, Bulletin 4480
• Canola, NSW Agriculture
• Canola Check Tool Kit, Primary Industries and
Resources SA.
• Canola Cache, Kondinin
Each state department of agriculture / primary industries
also have a series of farm notes / fact sheets on canola
production which are updated on a regular basis.
Using
this
Guide
This guide will help you identify
and manage blackleg and sclerotinia
the two most damaging diseases to
canola crops across Australia.
For identification of other canola
diseases refer to the “Canola
Diseases Back Pocket Guide” or
“Canola: The Ute Guide”.
Blackleg
Spread of the disease
Number of blackleg spores
Number of airborne spores landing on the ground
in relation to the distance from canola residues
0
300
500
1000
Blackleg is the most common and serious disease of
canola in Australia.
Autumn rains bring a massive release of spores from
infected stubbles above the soil surface. The more stubble
and the closer it is to emerging canola crops the greater
the risk of severe infection. Blackleg spores are carried by
winds to nearby seedling crops. Most spores travel less
than 300 m, but some can travel several kilometres. In
general stubble less than 12 months old releases over 99%
of all blackleg spores, older stubble accounts for very few
spores. However, in some cases significant spore release
can occur from two year old stubbles.
2000
Distance (metres)
courtesy Department of Agriculture, WA
Photo Department of Agriculture, WA
Seedling
infected with
Blackleg
Infection
Grey, circular spots (lesions) with black specks (fruiting
bodies) form on the cotyledons and leaves. Lesions can
appear on any part of the plant and even occur on
resistant varieties.
Blackleg grows from the lesion down within the stem to
the crown where it will cause a constriction in the stem
just below the first leaves . It can be confused with
“damping off”, but is distinguished by a characteristic
thinning of the stem immediately below the cotyledons.
Photo Department of Agriculture, WA
Heavy infection soon after germination can kill seedlings
and rosette size plants. Plants will continue to die right
through the growing season, causing older plants to
lodge. Partial constriction of the stem will reduce seed
size and oil percentage.
Leaf lesions
Cool showery weather in autumn and winter favours
infection and spread of the disease.
High Risk Areas
Include the combination of:
• High rainfall districts with greater than 400 mm
annual rainfall.
• And districts which had a HIGH percentage of
paddocks producing canola during the previous season.
Photo Department of Agriculture, WA
Recommendation:
Only sow varieties with Canola Association of Australia
Blackleg resistant rating of 6 or more (Resistant and
highly resistant). Resistant rating is 9 (highly resistant)
to 1 (susceptible).The latest blackleg resistance rating
brochures are available from seed merchants and
Department of Agriculture offices. In WA, growers
should refer to the latest WA blackleg resistance ratings
on canola varieties farmnote.
Severe crown canker
Any recommendations contained in this
publication do not necessarily represent
GRDC policy. No person should act on the
basis of the contents of this publication,
whether as to matters of fact or opinion or
other content, without first obtaining
specific, independent professional advice
which confirms the information contained
in this publication.
Keep this year’s crop as far as possible from last year’s
stubble.
The “Managing Blackleg and Sclerotinia in Canola”
Back Pocket Guide is part of a series of Back Pocket
Guides published by GRDC.
For free copies please contact:
GRDC Publications Manager
PO Box E6 Kingston, ACT 2604
Telephone: 02 6272 5525
Facsimile: 02 6271 6430
Email:
[email protected]
GRDC
Grains
Research &
Development
Corporation
POCKET GUIDE
Managing Blackleg and
Sclerotinia in Canola: THE BACK
Using
this
Guide
This guide will help you identify
and manage blackleg and sclerotinia
the two most damaging diseases to
canola crops across Australia.
For identification of other canola
diseases refer to the “Canola
Diseases Back Pocket Guide” or
“Canola: The Ute Guide”.
Blackleg
Spread of the disease
Number of blackleg spores
Number of airborne spores landing on the ground
in relation to the distance from canola residues
0
300
500
1000
Blackleg is the most common and serious disease of
canola in Australia.
Autumn rains bring a massive release of spores from
infected stubbles above the soil surface. The more stubble
and the closer it is to emerging canola crops the greater
the risk of severe infection. Blackleg spores are carried by
winds to nearby seedling crops. Most spores travel less
than 300 m, but some can travel several kilometres. In
general stubble less than 12 months old releases over 99%
of all blackleg spores, older stubble accounts for very few
spores. However, in some cases significant spore release
can occur from two year old stubbles.
2000
Distance (metres)
courtesy Department of Agriculture, WA
Photo Department of Agriculture, WA
Seedling
infected with
Blackleg
Infection
Grey, circular spots (lesions) with black specks (fruiting
bodies) form on the cotyledons and leaves. Lesions can
appear on any part of the plant and even occur on
resistant varieties.
Blackleg grows from the lesion down within the stem to
the crown where it will cause a constriction in the stem
just below the first leaves . It can be confused with
“damping off”, but is distinguished by a characteristic
thinning of the stem immediately below the cotyledons.
Photo Department of Agriculture, WA
Heavy infection soon after germination can kill seedlings
and rosette size plants. Plants will continue to die right
through the growing season, causing older plants to
lodge. Partial constriction of the stem will reduce seed
size and oil percentage.
Leaf lesions
Cool showery weather in autumn and winter favours
infection and spread of the disease.
High Risk Areas
Include the combination of:
• High rainfall districts with greater than 400 mm
annual rainfall.
• And districts which had a HIGH percentage of
paddocks producing canola during the previous season.
Photo Department of Agriculture, WA
Recommendation:
Only sow varieties with Canola Association of Australia
Blackleg resistant rating of 6 or more (Resistant and
highly resistant). Resistant rating is 9 (highly resistant)
to 1 (susceptible).The latest blackleg resistance rating
brochures are available from seed merchants and
Department of Agriculture offices. In WA, growers
should refer to the latest WA blackleg resistance ratings
on canola varieties farmnote.
Severe crown canker
Any recommendations contained in this
publication do not necessarily represent
GRDC policy. No person should act on the
basis of the contents of this publication,
whether as to matters of fact or opinion or
other content, without first obtaining
specific, independent professional advice
which confirms the information contained
in this publication.
Keep this year’s crop as far as possible from last year’s
stubble.
The “Managing Blackleg and Sclerotinia in Canola”
Back Pocket Guide is part of a series of Back Pocket
Guides published by GRDC.
For free copies please contact:
GRDC Publications Manager
PO Box E6 Kingston, ACT 2604
Telephone: 02 6272 5525
Facsimile: 02 6271 6430
Email:
[email protected]
GRDC
Grains
Research &
Development
Corporation
POCKET GUIDE
Managing Blackleg and
Sclerotinia in Canola: THE BACK
Using
this
Guide
This guide will help you identify
and manage blackleg and sclerotinia
the two most damaging diseases to
canola crops across Australia.
For identification of other canola
diseases refer to the “Canola
Diseases Back Pocket Guide” or
“Canola: The Ute Guide”.
Blackleg
Spread of the disease
Number of blackleg spores
Number of airborne spores landing on the ground
in relation to the distance from canola residues
0
300
500
1000
Blackleg is the most common and serious disease of
canola in Australia.
Autumn rains bring a massive release of spores from
infected stubbles above the soil surface. The more stubble
and the closer it is to emerging canola crops the greater
the risk of severe infection. Blackleg spores are carried by
winds to nearby seedling crops. Most spores travel less
than 300 m, but some can travel several kilometres. In
general stubble less than 12 months old releases over 99%
of all blackleg spores, older stubble accounts for very few
spores. However, in some cases significant spore release
can occur from two year old stubbles.
2000
Distance (metres)
courtesy Department of Agriculture, WA
Photo Department of Agriculture, WA
Seedling
infected with
Blackleg
Infection
Grey, circular spots (lesions) with black specks (fruiting
bodies) form on the cotyledons and leaves. Lesions can
appear on any part of the plant and even occur on
resistant varieties.
Blackleg grows from the lesion down within the stem to
the crown where it will cause a constriction in the stem
just below the first leaves . It can be confused with
“damping off”, but is distinguished by a characteristic
thinning of the stem immediately below the cotyledons.
Photo Department of Agriculture, WA
Heavy infection soon after germination can kill seedlings
and rosette size plants. Plants will continue to die right
through the growing season, causing older plants to
lodge. Partial constriction of the stem will reduce seed
size and oil percentage.
Leaf lesions
Cool showery weather in autumn and winter favours
infection and spread of the disease.
High Risk Areas
Include the combination of:
• High rainfall districts with greater than 400 mm
annual rainfall.
• And districts which had a HIGH percentage of
paddocks producing canola during the previous season.
Photo Department of Agriculture, WA
Recommendation:
Only sow varieties with Canola Association of Australia
Blackleg resistant rating of 6 or more (Resistant and
highly resistant). Resistant rating is 9 (highly resistant)
to 1 (susceptible).The latest blackleg resistance rating
brochures are available from seed merchants and
Department of Agriculture offices. In WA, growers
should refer to the latest WA blackleg resistance ratings
on canola varieties farmnote.
Severe crown canker
Any recommendations contained in this
publication do not necessarily represent
GRDC policy. No person should act on the
basis of the contents of this publication,
whether as to matters of fact or opinion or
other content, without first obtaining
specific, independent professional advice
which confirms the information contained
in this publication.
Keep this year’s crop as far as possible from last year’s
stubble.
The “Managing Blackleg and Sclerotinia in Canola”
Back Pocket Guide is part of a series of Back Pocket
Guides published by GRDC.
For free copies please contact:
GRDC Publications Manager
PO Box E6 Kingston, ACT 2604
Telephone: 02 6272 5525
Facsimile: 02 6271 6430
Email:
[email protected]
GRDC
Grains
Research &
Development
Corporation
POCKET GUIDE
Managing Blackleg and
Sclerotinia in Canola: THE BACK
Blackleg
Lower Risk Areas
Include the combination of:
• Lower rainfall areas with less than 400 mm annual
rainfall.
Photo Department of Agriculture, WA
• And districts which had a LOW percentage of
paddocks producing canola during the previous
season.
Blackleg lesion on a canola pod
Recommendation:
Only sow varieties with Canola Association of Australia
Blackleg resistant rating of 5 or more (moderately
resistant, resistant and highly resistant). In WA, growers
should refer to the latest WA blackleg resistance ratings
on canola varieties farmnote. In districts where there is
very little stubble residue, and paddocks are well isolated
from residues, varieties with a rating of 4 may be grown.
Managing the Risk of Blackleg
Rainfall is only a guide to the likely risk of blackleg
and some properties could be in a higher risk category,
due to the high intensity with which canola has been
grown in the district over the last year.
Spores on canola stubble
Minimise the risk of crop damage due to blackleg by:
• Choosing a variety with the highest level of disease
resistance which is adapted to your rainfall district.
• Maximising the distance between last year’s canola
stubble and this years crop; upwind is better.
• Reduce the amount of canola residue by grazing,
burying or burning etc.
Stem canker can cause plants to lodge
Sclerotinia
Stem Rot
White fluffy growth of Sclerotinia
on canola stem
The application of systemic fungicides may be a useful
tool for blackleg management. However, the profitability
of this needs to be considered.
Individual plants or
patches die
Sclerotinia stem rot appears as white fluffy growth
usually just above the soil level on the stem, however
infection can occur 30 to 45 centimetres above the soil
surface. Crop growth stops above this point and plants
wilt and ripen prematurely. Severely affected plants
will die and lodge. Affected area on the plant is usually
greyish white or brownish white.
The disease is widespread in canola growing areas,
but generally only severe in NSW and NE Victoria.
It is favoured by warm damp weather during flowering.
In most canola growing regions in Australia the
climatic conditions are not favourable for Sclerotinia.
Black, irregular-shaped fungal fruiting bodies (sclerotia)
form inside infected stems, and in moist weather
conditions they can also form on the outside of the
affected area. Infections high on the stems can result
in contamination of the seed.
Sclerotinia can survive as sclerotia in the soil for up to
8 years. The fungus probably also survives in the soil
by colonising the roots of other plant species such as
capeweed, lupins and peas.
Black fungal fruiting bodies (sclerotia)
inside infected stems
Control
• Currently there are no control recommendations
for Australia.
• In Canada the only control is to spray fungicides
during flowering, although this is likely to work in
Australia it may prove too costly due to our extended
flowering time and consequently multiple sprays
required (no fungicides are registered). If considering
using fungicides check withholding periods.
• Cultural methods for reducing the amount of
inoculum include:
– Use cereals in the rotation as grasses are not
affected by sclerotinia (all broad leaf crops are
susceptible).
– Sow canola seed that is free of sclerotinia
contamination (sclerotia).
– Reduce stubble residues.
– If you have a sclerotinia problem this season you
will not necessarily have a problem next season
as the disease is dependant on specific weather
conditions during the flowering period.
Graph and photos courtesy
“Beating Blackleg in WA” Bulletin,
Martin Barbetti, Ravjit Khangura,
Moin Salam, Paul Carmody, Mark
Sweetingham, Graham Walton and
Christine Zaicou-Kunesh; Department
of Agriculture, WA
Guide concept: Ross Andrews, GRDC
Photography: Stephen Marcroft, Mark
Stanley, Ravijit Khangura, Martin
Barbetti
Text: Stephen Marcroft, Trent Potter,
Paul Parker, Ravjit Khangura
This guide should be used in association with the
following publications:
• Canola: The Ute Guide
• Your Guide to Growing Golden Canola, Department
of Agriculture, WA
• ‘Managing Blackleg-a growers guide to making the
right decisions in managing blackleg disease of canola
in Western Australia’, Department of Agriculture,
WA, Bulletin 4480
• Canola, NSW Agriculture
• Canola Check Tool Kit, Primary Industries and
Resources SA.
• Canola Cache, Kondinin
Each state department of agriculture / primary industries
also have a series of farm notes / fact sheets on canola
production which are updated on a regular basis.
Using
this
Guide
This guide will help you identify
and manage blackleg and sclerotinia
the two most damaging diseases to
canola crops across Australia.
For identification of other canola
diseases refer to the “Canola
Diseases Back Pocket Guide” or
“Canola: The Ute Guide”.
Blackleg
Spread of the disease
Number of blackleg spores
Number of airborne spores landing on the ground
in relation to the distance from canola residues
0
300
500
1000
Blackleg is the most common and serious disease of
canola in Australia.
Autumn rains bring a massive release of spores from
infected stubbles above the soil surface. The more stubble
and the closer it is to emerging canola crops the greater
the risk of severe infection. Blackleg spores are carried by
winds to nearby seedling crops. Most spores travel less
than 300 m, but some can travel several kilometres. In
general stubble less than 12 months old releases over 99%
of all blackleg spores, older stubble accounts for very few
spores. However, in some cases significant spore release
can occur from two year old stubbles.
2000
Distance (metres)
courtesy Department of Agriculture, WA
Photo Department of Agriculture, WA
Seedling
infected with
Blackleg
Infection
Grey, circular spots (lesions) with black specks (fruiting
bodies) form on the cotyledons and leaves. Lesions can
appear on any part of the plant and even occur on
resistant varieties.
Blackleg grows from the lesion down within the stem to
the crown where it will cause a constriction in the stem
just below the first leaves . It can be confused with
“damping off”, but is distinguished by a characteristic
thinning of the stem immediately below the cotyledons.
Photo Department of Agriculture, WA
Heavy infection soon after germination can kill seedlings
and rosette size plants. Plants will continue to die right
through the growing season, causing older plants to
lodge. Partial constriction of the stem will reduce seed
size and oil percentage.
Leaf lesions
Cool showery weather in autumn and winter favours
infection and spread of the disease.
High Risk Areas
Include the combination of:
• High rainfall districts with greater than 400 mm
annual rainfall.
• And districts which had a HIGH percentage of
paddocks producing canola during the previous season.
Photo Department of Agriculture, WA
Recommendation:
Only sow varieties with Canola Association of Australia
Blackleg resistant rating of 6 or more (Resistant and
highly resistant). Resistant rating is 9 (highly resistant)
to 1 (susceptible).The latest blackleg resistance rating
brochures are available from seed merchants and
Department of Agriculture offices. In WA, growers
should refer to the latest WA blackleg resistance ratings
on canola varieties farmnote.
Severe crown canker
Any recommendations contained in this
publication do not necessarily represent
GRDC policy. No person should act on the
basis of the contents of this publication,
whether as to matters of fact or opinion or
other content, without first obtaining
specific, independent professional advice
which confirms the information contained
in this publication.
Keep this year’s crop as far as possible from last year’s
stubble.
The “Managing Blackleg and Sclerotinia in Canola”
Back Pocket Guide is part of a series of Back Pocket
Guides published by GRDC.
For free copies please contact:
GRDC Publications Manager
PO Box E6 Kingston, ACT 2604
Telephone: 02 6272 5525
Facsimile: 02 6271 6430
Email:
[email protected]
GRDC
Grains
Research &
Development
Corporation
POCKET GUIDE
Managing Blackleg and
Sclerotinia in Canola: THE BACK