Aliette is our best control for Downey Mildew. It can also be used for the damping off organism Pythium and root and collar rot organism Phytopthora as a foliar spray or soil drench.
Common Rose Diseases Controlled, Suppressed or Prevented: Downy Mildew & Phytopthora Root Rot
Rate & Combinations:
.25 to .5 tbl per gal of water as a drench. 1.5 tbl. per gal. of water as a foliar spray.