Rose Gardening Tips

How to Deal with Common Rose Diseases

Credit: Connie Luayon

Some flower gardeners say that roses are delicate to grow.  Whether that is true or not, rest assured that there is a solution to common rose problems.  To make sure that your roses remain healthy, regularly check them for certain diseases.  Here are some tips to help you deal with common rose diseases:

1. Black Spot

What happens: Black circular spots with fringed edges appear on leaves
What to do: These black spots cause the leaves to turn yellow.  To solve this problem, remove the infected leaves and pick up any fallen infected leaves around the rose.  Artificial sprays may be used to prevent or treat black spots on roses.

2. Powdery Mildew

What happens: Stunted or malformed young canes
What to do: Powdery mildew is a fungal disease that invades leaves, stems and buds with wind spread white powder.  The fungus makes the leaves curl and turn purple.  To get rid dof this disease, spray with Funginex or Benomyl to treat this fungal disease.

3. Rust

Symptoms: Blistered underside of leaves
What to do: Rust is marked by orange-red blisters on the underside of the leaves.  These blisters turn black in autumn.  The disease can survive the winter and attack young rose plants in the spring.  Before winter arrives, collect and discard blistered leaves.  Spray Benomyl or Funginex every 7-10 days.

4. Deformed or stunted leaves and flowers

These are caused by tiny yellow, red or green spiders residing on the underside of the rose leaves.  These spider mites suck the plant’s juices, making the leaves and flowers grow malformed or remain stunted.

5. Tiny white webs on the underside of leaves

Do you notice the leaves becoming weak and mottled with tiny white webs under them?  This disease is caused by aphids—small, soft-bodied insects that are usually brown, green or red in color.  Aphids are often clustered under leaves and flower buds, and they suck plant juices from young, tender buds.  Get rid of these bugs by spraying Malathion or Diazinon.

6. Thrips

What happens: Some flowers don't open or are deformed when they open
What to do: Thrips is caused by slender, brown-yellow bugs with fringed wings.  They suck the juices from flower buds, making the flowers grow deformed or unable to open properly.  Treat this problem by cutting and discarding the infested flowers.  If you wish to annihilate the bugs, spray the roses with Orthene or Malathion.

Reminder: Always wear protective gloves or outfit when spraying insecticide.

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