Cabbage ring spot on cabbage-Ghana: Mycosphaerella brassicicola (syn. Cercospora albomaculans) ; black ringspot of crucifers
Publication: PlantwisePlus Knowledge Bank
Pest Management Decision Guides
Pictures
Prevention
•
Heat-treat seeds with hot water at 50°C for 30 minutes, dry, then plant, or purchase fungicide-treated seeds (see yellow column)
•
Establish nurseries far away from diseased brassicas (at least 200m)
•
Prepare non-dense seedbed to ensure aeration & drying
•
Plant resistant varieties like Oxylus and KK crosses
•
Plant new crops as far as possible away from existing brassica crops
•
Plough diseased residues deeply soon after harvest. In contrast, slightly tillaging residues under, supports the disease survival
•
Do not irrigate diseased fields after 3pm and before 10am, as wind and water splash spreads the disease
•
Do not replant cabbages on the same land until residues have rotten away. Alternatively, rotate cabbage with maize or soybeans for 2-3 years
Monitoring
•
Ring spot is an airborne fungus disease that also survives on crop debris
•
Disease is more severe during rainy season, or in frequent watering or irrigation
•
Monitor twice during first 2 weeks of germination
•
Inspect seedlings twice a week for ring spots. If seen, consider action
•
Look for dark ring spots up to 2 cm on outer part of leaves, with dark grey centres surrounded by a yellowish zone. Inside spots may be whitish.
•
Heavy infestation makes cabbage heads spotty and shrivelled. Infected cabbage cannot be cured.
•
When 5-20% of young cabbage heads show a few dark concentric spots, consider action to protect unaffected cabbage and to prevent disease in storage
•
If dark spots developed on stored cabbage heads, action is too late
Direct Control
•
Remove the seedlings with ring spots in nursery, to prevent disease spread in the field
•
Remove plants if affected in field to limit further spread
Restrictions
•
It is impossible to cure an infected cabbage plantation. Consider early protective actions if disease had been present in the area in previous seasons
•
When using a pesticide or botanical, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, pre-harvest interval, max number of sprays, restricted re-entry interval. Do not empty into drains and water sources.
•
Pre-harvest intervals of pesticides in a certain crop must also be followed for the intercrop, and are sometimes even longer
•
Always consult recent list of registered pesticides Ghana
Direct Control
Apply Mancozeb based products once every week from two weeks after germination to prevent disease infection if threshold is reached. Then regular sprays on already established crop during cool weather, not during rain. See product label for dosage. FRAC class M3, multi-site action
WHO toxicity class U (Unlikely to present acute health hazard in normal use). Reach coverage of leaves to achieve protection. Pre-harvest interval 21 days. Restricted entry interval: ½ day after spray
Purchase certified seeds treated with Thiram based products from agro-input dealers. Non-systemic protective fungicide only protects the seed but not the germinated crop. FRAC class M3, multi-site action
WHO toxicity class II (moderately acutely hazardous). Do not treat seeds yourself. Do not eat treated seeds and do not feed to animals
Indexing Terms
Descriptors
- black ringspot of crucifers
- cabbage ringspot
- cabbages
- chemical control
- control
- cultivars
- cultural control
- decay
- deep ploughing
- disease control
- disease resistance
- extension
- fungal diseases
- fungicides
- hot water treatment
- mancozeb
- monitoring
- pathogenicity
- pathogens
- pest management
- pesticides
- pests
- physical control
- plant disease control
- plant diseases
- plant pathogenic fungi
- plant pathogens
- planting stock
- ploughing
- rotations
- seed treatment
- seeds
- storage decay
- thiram
- varietal resistance
- varieties
Organism Descriptors
Identifiers
- climate smart agriculture
- Cercospora albomaculans
- cultivated varieties
- deep plowing
- fungus
- pest management decision guides
- phytopathogenic fungi
- phytopathogens
- plant-pathogenic fungi
- cabbage ring spot
- plowing
- resistance to disease
- advisory services
- extension activities
- fungistats
- planting materials
- crop rotation
- rotational cropping
- deterioration in storage
- thiuram
- TMTD
- subsaharan Africa
Geographical Locations
Broader Terms
- Brassicaceae
- Brassicales
- eudicots
- angiosperms
- Spermatophyta
- plants
- eukaryotes
- Brassica
- Brassica oleracea
- Mycosphaerellaceae
- Capnodiales
- Dothideomycetes
- Pezizomycotina
- Ascomycota
- fungi
- Mycosphaerella
- Pseudocercosporella
- Africa
- ACP Countries
- Anglophone Africa
- Commonwealth of Nations
- lower-middle income countries
- medium Human Development Index countries
- West Africa
- Africa South of Sahara
Information & Authors
Information
Published In
Pest Management Decision Guides
Pest Management Decision Guide: Green and Yellow List
Applicable geographic locations
Africa, Ghana
Copyright
© CABI 2017. This article is published under aCreative Commons Attribution-ShareAlike 4.0 International License (CC BY-SA 4.0)Published under a CC-BY-SA 4.0 licence
History
Issue publication date: 1 January 2013
Published online: 12 October 2017
Language
English
Authors
Metrics & Citations
Metrics
SCITE_
Citations
Export citation
Select the format you want to export the citations of this publication.
EXPORT CITATIONSExport Citation
View Options
View options
Get Access
Login Options
Check if you access through your login credentials or your institution to get full access on this article.