Stem Canker (Coniothyrium wernsdorffiae)
Reddish brown, often slightly sunken spots in the eye area,
usually on canes from the preceding year. The affected canes die back.
Stem canker is caused by several different parasitic fungi entering the stem
through wounds or dying tissue.Cankers often appear on plants weakened
due to black spot.
Cause: Soggy soil, unbalanced fertilizing. Often affects shrub and climbing roses.
Prevention: Drainage and good soil aeration. Fertilizing less promotes soil life. Treat any wounds with wound paint and check for ideal location.
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