Pests and Diseases of Roses

Pests and Diseases of Roses

Aphids (various species)

Pests and Diseases of Roses - aphids on roses Aphids are common and widespread, affecting a wide range of plants as well as roses.

Typical symptoms: Green or pinkish aphids appear on plants, usually on soft shoots and buds during spring, when they can damage weak plants.

Prevention and treatment: See Aphids as Garden Pests


Blackspot (Diplocarpon rosae

This is extremely common and widespread.

Typical symptoms: Dark brown or black blotches appear on leaves. Blackspot is worse in warm wet weather. (See Plant Diseases – Understanding the Problem)

Prevention and treatment: Choose less susceptible varieties (see Organic Gardening – Preventing Problems). Do not grow roses in damp, overcrowded conditions. Collect up all fallen leaves in autumn; mulch plants before new growth begins in spring. Prune affected plants severely in spring.


Caterpillars (various species)

Typical symptoms: Irregular holes appear in leaves and flower buds where the caterpillars have eaten the plants. Caterpillars may be visible.

Prevention and treatment: Examine plants regularly and crush any eggs and caterpillars found. Remove mulches over winter.


Leaf-rolling sawfly (Blennocampa pusilla)

Typical symptoms: Leaves of affected plants roll tightly. Damage can be unsightly but rarely harms the plant.

Prevention and treatment: Pick off affected leaves as soon as possible. If the attack is more severe, spray with insecticidal soap. Remove mulches and cultivate the soil under affected plants in winter to expose pupae to predators.


Powdery mildew (Sphaerotheca pannosa)

Typical symptoms: A powdery coating appears on leaves, stems, buds and, occasionally, flowers. Leaves may drop prematurely. Powdery mildew is worse in hot, dry locations.

Prevention and treatment: See How to Treat Common Plant Diseases


Rose cankers (various fungi)

Typical symptoms: Brown patches appear on stems; shoots die back. Sometimes a canker will girdle the stem.

Prevention and treatment: Cut out dead or dam- aged wood regularly and remove cankered stems. Do not leave any stumps when pruning.


Rose slugworm (Endelomyia aethiops)

Typical symptoms: Also known as rose skeletonizer, this pest skeletonizes leaves. Damage can be unsightly but rarely harms the plant.

Prevention and treatment: Pick off any affected leaves as soon as possible. If the attack is more severe, spray with insecticidal soap. Remove mulches and cultivate the soil under affected plants in winter to expose pupae to predators.


Rust (Phragmidium tuberculatum)

Typical symptoms: Bright orange pustules are visible on the underside of the leaves.

Prevention and treatment: Grow less susceptible varieties. Collect up and burn affected leaves and fruit in autumn.


02. February 2011 by Dave Pinkney
Categories: Organic Gardening, Pests and Diseases, Plant Care, Rose Care, Roses | Tags: , | Comments Off on Pests and Diseases of Roses

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