Stemphylium purple spot

Tan-to-brown sunken, elliptical lesions with purple edges appear on infected spears, stems and fern. As the disease spreads the lesions expand and merge together killing the affected tissue and eventually causing wide-spread defoliation. Small black spores (pseudothecia) may be visible in the centre of the lesion, particularly on the previous season's crop residue.
Initial infections commonly occur on the bottom 30 cm (12 inches) of the stem, moving upwards onto the fern as the season progresses.