Black Spot on roses

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Black Spot on roses

• Brett Hordesky
• Brady Swicker
• Mandy uhlman
• Colin Chalmers

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Description

• Dark brown to black leaf spots on the upper leaf
  surface. The leaf spot lesions are circular and
  have irregular, feathery margins. Individual
  leaves may develop multiple leaf spots and during
  the beginning of growing seasons the black spots
  start developing on the bottom of the leaves and
  will move upward through the plant as the seasons
  progresses.

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Life cycle

• Black spot produces infectious spores through out
  the whole year, which causes repeated infections
  in warm, wet weather. In winter time the fungus
  seeks shelter under fallen leaves and diseased
  branches, and as soon as it warms up the black
  spots begin to spread again.

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Preventions and control

• Prevention is the best defense for black spots.
  Leaf litter needs to be taken away from the area
  since the spores over-winter on infected leaves.
  Also fungal sprays are advised, weekly spraying
  between spring and autumn are advised. And proper
  pruning will remove spores that have over-
  wintered on the plant.

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Transmission

• The fungus occurs most in clean air areas and
  occurs less frequently in areas where populations
  is a problem. It is spread mainly in warm weather
  by water-splash or wind-blown rain. The fungus
  however has not been found to survive in soil and
  spores blown to benches and tools often die
  within a month.

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• Host plants
• Its host plants are mainly roses but also
  sometimes ornamental plants and garden plants can
  become infected.
• Cup flowers
• Oregano
• Lemon palm
• Range
• All through out North America

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Rose plants with black spot resistance

• David Thompson
• Bebe Lune
• Coronado
• Ernest.H.Morse
• Forty-niner
• Grand Opera