Dr. Phyto

Northern red oak

Quercus rubra

Diseases & pests on this plant

• Oak wiltBretziella fagacearum

  Leaves wilt, turn bronze and drop from the top of the crown downward; red oaks can die within weeks while white oaks decline more slowly; brown to black streaking appears in the outer sapwood.

• almond leaf scorchXylella fastidiosa subsp. multiplexEU-notifiable quarantine organism

  Marginal leaf scorch progressing inward, premature leaf drop on individual branches, reduced nut size and oil content, gradual canopy decline over 3–5 years.

• sudden oak death / Ramorum blightPhytophthora ramorumEU-notifiable quarantine organism

  Dark brown leaf blotches often starting at leaf tip + spreading along midrib, bleeding cankers on stems + trunks (oozing dark sap), wilting + dieback of branches, complete tree death possible within 2 years (oak + larch); shrub hosts (Rhododendron) show leaf blackening + stem dieback.