Black Spot

Black spot is a common fungal disease causing dark brown to black leaf spots on the upper surfaces.

Identify the problem Identify the problem

Black spot is caused by fungus. Dark-brown to black leaf spots develop on the upper leaves, which eventually become yellow and drop.

Black spot can be distinguished from other leaf spot diseases by its fringed edges and dark black colour. Raised, reddish-purple spots may also appear on the plant. Warm, humid conditions favour its germination and growth.


  • Good garden hygiene is important for treating black spot. Remove garden litter, ensure plants have plenty of sunlight and good circulation. During the growing season, overhead watering should be avoided. 
  • To control spray with PLANThealth Rose Force or Spectrum.
  • Prevention is always better than cure. Measures to improve black spot disease control include ensuring appropriate planting sites, the use of resistant cultivars, and regular pruning (for more information read Protect Your Plants from Disease). PLANThealth Rose Force and Spectrum are a systemic fungicide and insecticide combinations that will help cure and prevent black spot.

Did You Know Did You Know

Black spot disease is caused by variety of fungi:

  • Black spot in apples also known as apple scab - Venturia inaequalis
  • Citrus black spot - Guignardia citricarpa
  • Rose black spot - Diplocarpon rosae

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Solutions for you...

Plant Health Spectrum Plus

Plant Health Spectrum Plus

Triple action fungicide, insecticide and foliar feed for roses and ornamentals.

Plant Health Spectrum

Plant Health Spectrum

Insect pest and disease control for roses and ornamentals.

Organic Super Sulphur

Organic Super Sulphur

Organic control of diseases - powdery mildew, blackspot and rust. Plus control of moss, lichen and mites.


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