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Roses are not immune to insects or diseases. It is crucial that you know what to look for and how to combat the common pestilences that may afflict your roses.


Grasshoppers, aphids, thrips, spider mites, rose scales, leafhoppers, and nematodes are common insects that afflict your roses. Jericho Nursery has the best insecticides for each of these bugs.

Grasshoppers hop from one plant to the next chewing your leaves and blooms and compromising the beauty of your plants. They can be combatted by Malathion or Grashopper Spore.

Thrips are so small they are nearly invisible. They love to colonize on your rose flowers. To combat thrips, concentrate insecticide spray on the flowers unless you also have other insects on the leaves.

Spider mites are small, spider-like pests that make web colonies on the undersides of your rose leaves. Dormant oil sprays are effective in combatting them before spring. If spider mites exist during the peak season of your roses, use a Kelthane miticide as prescribed by Jericho Nursery.

Nematodes are microscopic worms that colonize in the roots of the rose, impairing proper root growth. If the roots are too heavily affected, all your plants must be dug up and destroyed and a new rose garden must be started in a new area.

Aphids generally attack your roses in the spring when the plant is growing new leaves, stems, and blossoms. They suck on the rose juices, stealing important nutrients. Use a strong spray of water to wash them off or visit Jericho Nursery for the most effective insecticide.

Rose scales form communities on your rose canes and suck the rose juices and weaken the plant. They are best combatted by dormant spray in the winter months and soil-applied insecticides in the summer.

Leafhoppers, like aphids, suck vital juices out of your plant. Some transmit diseases that can kill your roses. These are best combatted by spoil-applied systemic insecticides or the daisy-based compound pyrethrum.



Diseases such as powdery mildew, rust, blackspot, rose gall, and crown gall can affect your roses in various parts of the plant.

Fungal Diseases

Powdery mildew is a white fungus that covers rose leaves and can cause serious damage. If you find powdery mildew, make sure water in the morning and not wet the leaves. Fertilize only as necessary, and spray a fungicide or sulfur on the leaves, as prescribed by one of our experts at Jericho Nursery.

Blackspot is another common leaf fungus. It starts on the lower leaves and quickly works its way up, manifesting in black spots that turn the leaves yellow before they fall off. Blackspot generally occurs during rainy, hot times of the summer. Blackspot can become resistant to fungicides, so consult with a Jericho Nursery staff about the best approach for treating blackspot.

Rust is yet another fungal disease. It is known for causing orange, rust-colored spots on the undersides of your leaves. Rust can be easily combatted with several fungicides.

Bacterial Diseases

Rose and Crown Gall are bacterial diseases that can destroy a rose bush. Rose gall is generally formed when a female wasp lays her eggs within an unopened leaf bud. This forms a moss-like lump on the branch. To remove rose gall, simply prune the affected branch.

Crown gall, though less common, is more aggressive. It can infect the entire rose bush and transfer to other bushes in your garden. It manifests in a round, 2-inch or larger growth. To preserve your rose, prune away any part that might be infected. If you believe the roots or crown of the rose are infected, the best course of action is to dig up and destroy the plant before it infects your other roses.

If you suspect that your roses are suffering from any of these insects or diseases, consult with a Jericho Nursery staff member. We will be happy to help you protect your roses.

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