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.
The disease is caused by Stemphyllium vesicarium .
Remove or bury crop residue in the fall to help limit infection.
