What's Bugging Your Annuals

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

flea beetles

Flea Beetles

Plants Affected:  Numerous annuals and perennials


Symptoms:  Numerous holes in foliage, about the size of a pinhead


Life Cycle:  Overwinter in soil beneath leaf debris, emerge in spring.  Adults feed on foliage, mate and lay eggs


Controls – Cultural or Non-chemical:  Clean up leaf debris and weeds in autumn


Controls – Chemical:  Spray adult beetles in spring before they lay eggs; Ambush, Dr. Doom House and Garden



Plants Affected: Annuals and perennials


Symptoms:  Ragged holes chewed in leaves, slime trails on leaves


Life Cycle:
•Overwinter as eggs in soil
• Hermaphrodite; every slug can lay eggs.  Eggs laid in batches of 10-0 in moist soil


Controls – Cultural or Non-chemical:
• Till soil to disturb eggs, expose eggs to natural predators
• Spread Diatomaceous earth or other gritty substances under plant leaves
• Spread iron based slug pellets (Sluggo or Safer’s) at base of plants, under foliage
• Beer traps, dishes filled with beer, set at soil level, may attract and drown slugs


Controls – Chemical:  Metaldehyde based pellets

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