Marin Rose Society

FAST FACTS - APHIDS
by Nanette Londeree, Master Rosarian

SIGNS

Large colonies of tiny insects on and below young flower buds and tender unfolding leaves

Molts and / or mummified skins of parasitized aphids

Sticky honeydew visible around insects; black sooty mold growing on honeydew

Presence of ants

SYMPTOMS

Weakened flower bud necks (pedicles) and distorted leaf growth

Possible curling, yellowing, and distortion of leaves and stunting of shoots

CAUSE

Small, pear shaped, soft-bodied insects with long, slender mouth parts that they use to pierce stems, leaves, and other tender plant parts and suck out plant fluids

Adults may be green, yellow, brown, red, or black

OPTIMAL CONDITIONS

Mild temperatures, 65° to 80°F

Presence of succulent new growth on roses

Most prevalent along the upwind edge of the garden and close to other sources of aphids

High levels of nitrogen fertilizer favor reproduction

TREATMENT

Prevention:

Check plants regularly to catch infestations early

Plant the garden to support natural enemies such as lady beetles, lacewings, syrphid fly larvae

Never use more nitrogen than necessary

Control ant populations

High summer temperatures tend to reduce populations

Elimination:

Knock them to the ground with a strong spray of water

Spray with an insecticidal soap

GOOD GUY / BAD GUY?

A bad guy, though generally more of a nuisance pest.

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FAST FACTS - APHIDS by Nanette Londeree, Master Rosarian

FAST FACTS - APHIDS
by Nanette Londeree, Master Rosarian