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.