Downy mildew was identified in Knock Out® rose samples submitted to the Plant Diagnostic Lab from a south-Jersey nursery this week. Knock Outs®, which have few problems, have been a favorite in New Jersey landscapes in recent years. Unfortunately, it seems this plant has met its Achilles’ heel.
Downy mildew on Double Knock Out® rose. Photo: Sabrina Tirpak, Rutgers PDL
