Black Spots on Roses

The black spots on rose leaves is a common and damaging fungal disease. This disease usually occur during wet summers. This fungal infection becomes a problem if the leaves are wet for several hours.

The black spot disease can cause complete defoliation of rose bushes. Know how to prevent, treat and control the black spots on roses easily using the following home remedy.
However you can prevent, treat and control the rose black spots as given below.

I propagated several roses by cuttings (rose propagation). They grew well but it was a great disappointment for me to notice many black spots and yellow leaves on them, the leaves felling down.

Circular black spots of size 4 mm to 1 cm in diameter appear on the upper side of the leaves. Infected leaves turn yellow and fall prematurely. If not treated, the disease spread quite quickly and the leaves are infected, covered with spots, turn yellow and fall.

Prevention of black spots on Roses

Black Spots on Rose Leaves due to fungus disease
Black Spots on Rose Leaves
  1. Buy a disease resistant rose plant from the nursery.
  2. Position the rose plant where they can get 6-8 hours of sunlight daily.
  3. keep enough distance between your rose plants to allow good air circulation.
  4. Prune out some centre branches and inward branches to allow internal air circulation.
  5. Keep the plant clean of diseased leaves fallen on the soil.
  6. Prune off all the diseased canes, cut a few inches into good wood.

Pink White Rose
Pink White Rose
Watering
  1. As excess moisture encourages black spot, do not wet the leaves and branches, just deep soak at the base.
  2. Water in the morning so that the leaves can dry out.
  3. Do not over-water your rose plants. 
  4. During hot and dry weather, water 2-3 times a week, while in cooler days, water weekly.

Control of Black Spot on Roses

  1. Remove infected leaves and branches and fallen leaves as soon as black spot appear to slow down further progression of the fungus.
  2. Fungicide

    Don't wait for the black spot to appear. Spray a fungicide on roses every 1 to 2 weeks with a fungicide during growing months.
    There are several fungicides including chlorothalonil, mancozeb, Thiophanate-methyl, trifloxystrobin, Ziram, etc.

Organic Solutions to Control Rose Black Spots

A spray of neem oil is a preventive spray which also helps control many rose pests. Other fungicides that may be applied periodically are copper spray, lime sulphur, potassium bicarbonate, sulphur and hydrogen peroxide.

Baking Soda Spray Recipe

I control black spots on my roses with my home remedy, i.e. a baking soda spray.
  1. Mix a 2 teaspoon of baking soda with a litre of water. Add 2-3 drops of dish washing soap.
  2. Spray both side of the leaves. Reapply weekly and after any rain.
  3. Baking soda makes it more difficult for black spot to infect plants.
  4. Do not wait for the spots to appear. Spray baking soda periodically on your roses.

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