Managing Blackleg and Sclerotinia in Canola
Transcription
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