| Purple Rot:Stemphyllium vesicarium |
Symptom:
- This disease can render the spears unmarketable by the presence of numerous purplish lesions or spots.
- The lesions are superficial, slightly sunken and purple. There can also be larger spots that are brown in the middle with a purple margin.
- Often these lesions will be more prevalent on one side of the spear that the other.
- On the asparagus fern there will be light brown lesions, up to 15mm long, with dark purple edges. In severe cases, defoliation and dieback can happen. Repeated defoliation can lead to a reduction in yield.
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Premature defoliation |
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Elliptical lesions |
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Purple Rot |
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Identification of pathogen:
- The disease is caused by Stemphyllium vesicarium.
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Stemphyllium vesicarium |
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Stemphyllium vesicarium conidia |
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Management:
- Remove or bury crop residue in the fall to help limit infection.
Source:
Images: http://www.omafra.gov.on.ca/IPM/english/asparagus/diseases-and-disorders/purple-spot-stemphylium.html
Plate and microscopic images: http://www.ast.go.kr/search/search_index, https://www.flickr.com/photos/lcisa/4475865401/
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