How to Control Black Spot on Roses

By eHow Home & Garden Editor

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Black spot is a fungus disease that appears as round, black spots on the leaves of rose plants. There may be a distinctive yellow band around the black spot and leaves may fall prematurely. Left untreated, black spot may infect young canes.

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Instructions

Difficulty: Moderately challenging

Things You’ll Need:

Dormant Oil
Bordeaux Mixture
Leaf Rakes
Plastic Bags
1 teaspoon baking soda

Step1

Look for black spot on the leaves of rose plants. This fungus disease will appear as round, black spots ringed by yellow tissue.

Step2

Water roses only from below. Try not to get the foliage wet when you water.

Step3

Water in the early morning hours so the rose plant has time to dry during the day.

Step4

Rake up any fallen leaves from the soil surrounding the plant. Black spot as well as other fungus diseases are transmitted by water splashing back up onto the leaves and stems.

Step5

Remove any diseased leaves. Pick off and destroy any foliage that has evidence of black spot. Dispose of infected foliage in a sealed plastic bag.

Step6

Dust roses infected with black spot with sulfur powder. Sulfur will not kill the fungus spores, but it will prevent a new generation from germinating.

Step7

Spray a solution of 1 tsp. baking soda mixed in 1 qt. warm water in the early morning hours.

Step8

Spray roses with a dormant oil or Bordeaux mixture when plants are dormant (usually in winter).

Tips & Warnings

Black spot is very difficult to eliminate once it appears. Prevention is the best form of defense.
Spray organic fungicides early in the day for best results.
Chemical fungicides are also available for the control of black spot.
Always use the least toxic method of pest control first.
If you choose to use a chemical fungicide, always wear protective clothing and safety gear, including a long-sleeved shirt, long pants, neoprene gloves, goggles and a respirator.

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Comments

clark6537 said

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on 5/21/2008 Tracyluvspurple, I know this is way late according to the date. I have heard that if you plant garlic around your rose bushes it keeps the beetles away and you can grow your own garlic. I have been reading about companion planting. I have just planted my garlic so I cannot tell you if it works yet but I figured its worth a try. Good Luck!