Tree Disease No' 7

1
Tree Disease No. 7

• Signs
• On the upper surface of the leaves tiny pustules
  are formed in the spots while on the lower leaf
  surface small circular lesions bordered with
  ribbon-like strands are formed. These lesions on
  the lower leaf surface are easily visible with a
  hand lens and are referred to as cluster cups.

2
Tree Disease No. 7

• Signs
• This disease is caused by the fungus
  Gymnosporangium juniperi-virginianae which
  overwinters as resting spores in the galls on
  junipers and cedars.

3
Cedar-Apple Rust
4
Tree Disease No. 8

• Host species
• Ornamental and fruit trees in the rose family
• apple (Malus sp.)
• crabapple (Malus sp.)
• hawthorn (Crataegus sp.)
• mountain ash (Sorbus sp.)

5
Tree Disease No. 8

• Symptoms
• Lesions (diseased areas) are often first noticed
  on leaves, where they most commonly occur on the
  upper leaf surface.