What's Bugging Your Roses

Insect Pests



Plants affected:  Numerous indoor and outdoor plants


Symptoms:  Severe infestations will cause curling/twisting of foliage, flowers to wilt and drop


Life Cycle:  Eggs hatch on host plants in spring, these nymphs give birth to ‘daughters’, within days the daughters give birth – up to 30 generations per summer


Cultural Control:
• Ladybird beetles/larvae, lacewings are natural predators
• Strong jet of water to knock aphids off plants


Chemical Control:  Doktor Doom House and Garden, End All

Leaf cutter bee

Leaf Cutter Bees

Plants Affected:  Rose, Lilac, Ash, Virginia Creeper

Half moon shapes cut out of leaves
• Use leaves to seal eggs into the cells of the hive


Life Cycle:
• Adults emerge from overwintering pupa in spring to rebuild nests

Adults may pollinate garden crops – do pollinate alfalfa


Cultural Control:  Not necessary, bees are beneficial!

rose curculio

Rose Curculio

Plants affected:  Rose


Symptoms:  Rose flowers will have petals riddled with small holes and wilted buds that have had their stems damaged.


Life Cycle:
Adults drill holes into buds to lay eggs. Eggs hatch and larvae feed on inside of flower buds/rose hips.
Affected buds/fruit fall off in autumn, larvae emerge and overwinter in soil. Larvae pupate in spring, adult beetle emerges shortly after.


Cultural Control:  Prune away infected buds/fruit, clean up any debris on ground early in fall.


Chemical Control:  If problem is suspected to be severe, spray plants with Doktor Doom House/Garden Garden residual insecticide.

slug sawfly on roses

Rose Slug Sawfly

Plants affected:  Roses


• Skeletonized leaves
Holes eaten in the leaves


Life Cycle:
• Adult sawfly emerge in early spring and lay eggs on the underside of the host plant leaves
• Larvae appear several weeks later and feed on the leaf tissue
• Drop in to soil to pupate


Cultural Control:
• Pick off affected leaves and discard, hose off with a strong jet of water
• Diatomaceous earth


Chemical Control:  Insecticidal soap, Doktor Doom House and Garden

Spider Mites

Spider Mites

Plants affected:  Numerous indoor and outdoor plants


Stippling—tiny dots in foliage
Yellowing of foliage—’haze’ on foliage


Life Cycle:
Can overwinter in various stages under debris or bark on host plants, in greenhouses
Become active in spring as foliage emerges


Cultural Control:
• Lacewings are natural predators
• Keep plants misted (they prefer dry conditions)
• Fall debris cleanup


Chemical Control:  End All, Doktor Doom House and Garden


Leaf Spot on Roses

Plants affected: Roses

Symptoms: Black spots appear on upper leaf surfaces, leaves eventually drop

Life Cycle:
• Overwinters in diseased canes and leaf debris beneath plants
• In spring, spores are spread by splashing water/rain. Fungal spores require 7 hours of moisture for infection to occur. Once infection occurs black spots start to develop

Cultural Control:
• Remove diseased leaves
• Prune roses to ensure good air circulation, do not water foliage (water base of plant)

Chemical Control:  Garden Sulphur applied as preventative every 7-10 days

Powdery mildew

Powdery Mildew

Plants Affected: Many perennials and annuals, popular hosts include garden phlox, speedwell, salvia, begonias, impatiens

Symptoms :
• White powdery spots, yellowing leaves
• Plants cannot manufacture as much food as they need – severe infestations will kill plants such as begonia


Life Cycle:  Specific spores (black spherical ones) overwinter on leaf debris and soil. High humidity favours spore production, while low humidity favours spore maturation and release


Cultural Control:
• Good circulation, full sun
• Clean up debris in fall


Chemical Controls: Garden Sulphur applied as preventative every 7-10 days

rust on roses


Plants Affected: Perennials, roses

Symptoms :
• Reddish orange spots on leaves and stems
• Wilting and defoliation follows

Life Cycle:  Spores overwinter on leaf debris and any dead/dying canes

Cultural Control: Prune out, good fall cleanup

Chemical Controls: Garden Sulphur applied as preventative every 7-10 days

Cultural Disorders

Chlorosis on roses


• leaves are yellow but veins remain green, may be some browning on the margins of leaves
• will be evident first on new growth, then work back to older leaves on a branch


• ensure loose, well-drained soil, avoid overwatering
• high soil alkalinity can also be a cause, plants can be fertilized with iron chelate for recovery

herbicide damage on roses

Herbicide Damage

• curling or cupping leaves
• discoloration between veins
• twisted, elongated stems


• use all herbicides according to label, note that herbicide can drift for several miles, it’s very difficult to ascertain where chemical drifts from
• keep damaged plants well-watered, most plants will recover

over watered rose


• wilting, yellowing leaves
• leaves will yellow from outside in
• Note: wilting is a symptom of BOTH over and underwatering, if plants are wilting don’t assume they require moisture until soil is checked by hand


• plants in lower lying areas will suffer in times of heavy rains; plant appropriate species in these areas
• for new and established plants, water only as required; check soil prior to watering

underwatered rose


• wilting, crispy or browned leaf edges


• water, especially for new transplants should be monitored daily during periods of extreme heat
• for new transplants, stick your hand into the soil to determine if moisture is required