Key Pests /Key Locations *

Key Plants

Monitoring

IPM Compatible Management Options *

Aphids (G,N, L)

Acanthus, Achillea, Alcea, Asclepias, Aster, Bellis, Dianthus, Digitalis, Heuchera, Helianthus, Helleborus, Hibiscus, Myosotis, Monarda, Papaver, Phlox, Primula, Rudbeckia, Salvia, Sedum, Veronica, and Viola etc.

May vector cucumber mosaic virus (CMV) which has a wide host range including: Ajuga, Aquilegia, Campanula, Delphinium, Dahlia, Lilium, and Phlox.

Inspect incoming plants and overwintered perennials before moving them into warmer production areas.  Look on the underside of leaves, buds and young growth for pear-shaped aphids. Look for honeydew, sooty mold and white shed skins. 

Look for mild mosaic and mottling. CMV may increase symptom expression when multiple viral infections occur. (No control). Discard infected plants.

Avoid excessive fertilizer applications. Hose off with water.

Natural enemies

Scout for ladybird beetles, parasitic wasps, syrphid fly larvae, lacewing larvae.

Chemical Options

Azatin, Ornazin (azadirachtin)

BotaniGard (Beauvaria)

Endeavor (pymetrozine)

Insecticidal Soap (I.S.4952CF, M-Pede)

Marathon, Merit (L)(imidacloprid)

Ultra-Fine Oil (horticultural oil)

Tristar (acetamiprid)

Repeat applications may be needed.

Potato Leafhoppers (N,L)

Aster Leafhoppers (N,L)

Alcea, Astilbe, Dahlia, and Hibiscus

Aster, Bellis, Campanula, Coreopsis, Delphinium, Echinacea, Gaillardia, Rudbeckia, and Salvia, etc.

Look for stippling and necrotic leaf edge burn on upper leaf surfaces. Look on lower leaf surfaces for nymphs and shed skins.

Transmit Aster Yellows. Infected plants  are stunted with shortened internodes, and witches broom growth. Flowers deformed, yellowish-green in color.

Manage weeds in and around fields to prevent infection of alternative hosts.

Rogue plants infected with aster yellows (no control).

Chemical Options

 Discus (imidacloprid & cyfluthrin) (N)

 Marathon, Merit (L)(Imidacloprid)

 Tristar (acetamiprid)

Chrysanthemum Lacebugs (N,L)

Aster, Chrysanthemum, Helianthus, Rudbeckia, and Solidago

Look for white stippling on foliage. Black fecal spots will distinguish lacebug feeding from mite or leafhopper damage. Look for shiny, black nymphs on underside of leaves.

Eliminate weeds

Natural enemies

Chrysoperla carnea (green lacewing) feed upon lacebug nymphs. Repeated releases may be needed.

Chemical Options

Insecticidal Soap or horticultural oil against nymphs on underside of leaves

Marathon, Merit (L)(imidacloprid)

Orthene (acephate)

Two-spotted spider mites (G,N,L)

Alcea, Aquilegia, Buddleia, Campanula, Delphinium, Filipendula, Gaillardia, Hemerocallis, Hydrangea, Iris, Lamium, Lavatera, Monarda, Nepeta, Papaver, Phlox, Potentilla, Primula, Rudbeckia, Scabiosa, Thalictrum, Verbena and Viola 

Look for mites and the signs of their damage in hot, dry environments or when plants are drought-stressed. Turn lower leaves over and look for spider mites, round eggs, white empty eggshells and shed skins along the veins.  Tapping foliage over a sheet of white paper makes it easier to see the faster-moving predatory mites.

Inspect incoming plants. Avoid dust and low humidity.  Hose off plants with water.

Natural enemies

Scout for fast- moving predatory mites, minute pirate bugs, spider mite destroyers (black ladybird beetle) and lacewing larvae.

Resistant cultivars of Buddleia include; B. marrubiifolia, B. davidii “ile de France”, B. davidii ‘Nanho’

Two-spotted spider mites (cont)

Chemical Options 

Floramite (bifenazate)

Ultra-fine Oil (horticultural oil)

1% horticultural oil plus Avid (abamectin)

Slower acting, but effective

Hexygon (hexythiazox)

Ovation (clofentezine)

TetraSan (etoxazole)

Cyclamen mites (G,N,L)

Aconitum, Clematis, Delphinium, Dahlia and Verbena

Look for puckering, crinkling and curling of leaves.  Infested buds may fail to open. Mites are small (1/100 inch) so examination under a microscope is often needed.

If detected early, it may be feasible to rogue out infected plants.

Chemical Options

Avid (abamectin)

Pylon (chlorfenapyr) (G)

Repeated applications needed.

Columbine Leafminers

(G,N, L)

Aquilegia

Look for snake-like (serpentine) white trails on the leaves. Look for puncture holes where females deposit eggs. Adults are a small, about ¾ of an inch long black fly.

Do nothing.

Handpick leaves when larvae are still in the leaves and before adults emerge.

Chemical Options

Azatin, Ornazin  (azadirachtin)

Avid (abamectin)

BotaniGard (Beauvaria) (suppression)

Conserve (spinosad)

Thrips

(G, N, L)

Daylily thrips

(N,L)

Alcea, Asclopias, Aster, Campanula, Chrysanthemum, Coreopsis, Crocosmia, Digitalis, Echinacea, Eupatorium, Lamium, Lupinus, Malva, Monarda, Penstemon, Platycodon, Polemonium, Phlox, Rudbeckia and Tanacetum

Hemerocallis, Iris

Inspect and isolate incoming plants for signs of larvae or adults. Gently blow into flower buds to agitate thrips. Tap flowers/foliage over a white sheet of paper to look for slender winged insects. Sticky cards to monitor for adults.  May spread tospoviruses.

Pull leaf sheaths apart to look for adults and larvae.

Eliminate weeds.

Use sticky cards to detect adults.

Discard heavily infested plants or flowers.

Natural enemies

Amblyseius cucumeris (predatory mites)

Hypoaspis miles (predatory mites)

Orius sp. (minute pirate bugs)

Chemical Options

Acetamiprid (TriStar)

Avid (abamectin)

Azatin, Ornazin (azadirachtin)

BotaniGard (Beauvaria)

Conserve (spinosad)

Ultra-fine Oil (horticultural oil)

Apply with small spray droplet size of less than 100 microns. Repeated applications needed.

Tospoviruses

(INSV/TSWV)

Wide host range: Campanula, Centranthus, Monarda, Penstemon, Phlox, Platycodon, Primula and many others.

Yellow or brown ring spots, brown or black stem sections. See Tospovirus database: http://www.agnr.umd.edu/tospo/

No control. Discard infested plants. Screen stock plants. Treat for western flower thrips. Take cuttings from clean stock plants.

Black Vine Weevils (G,N,L)

Astilbe, Bergenia,

Epimedium, Helleborus, Heuchera, Heucherella, Hosta, Phlox, Primula, Physostegia, Primula, Tricyrtis, Saxifraga, and Sedum etc.

In May and early June, look for C-shaped notching along leaf margins caused by adult feeding.  Look for adults in mulch and top layer of media or under containers. Adults feed primarily at night or during cloudy, misty days.   Look for white, legless larvae feeding on tender young roots especially on wilted plants or plants with notched foliage.

Handpick adults.

Inspect incoming plants.

Segregate infested plant material from new plantings. (adults can't fly)

Beneficial Nematodes

Heterorhabditis bacteriospora (Heteromask, Cruiser) H. megidis (Nemasys H) Treat in mid to late August. Keep soil moist.

Chemical Options

Preplant potting mix incorporation of

Talstar (bifenthrin)-rate varies with type of mix or Talstar drench.

Discus (imidacloprid & cyfluthrin)

Orthene (acephate) against adults.

Iris Borer (N, L)

Iris

Look for chewed leaves and leaf bleeding when iris leaves are about 5-6 inches high (late April- May).

Look for small, yellowish green larvae on the leaves by holding damaged leaves up to the sun.

Eggs are laid in the fall on the oldest iris leaves.

Clean up old foliage and debris in the fall or late winter to remove eggs.

Beneficial Nematodes

Heterhabditis bacteriophora, H. megidis

Steinernema feltiae Apply to kill larvae in rhizomes in July and August.

Apply systemic insecticide (Dimethoate  4EC (Restricted use) in the spring

Four-lined Plant Bugs (G, N, L)

Tarnished Plant Bugs (N, L)

Alchemilla, Chrysanthemum, Coreopsis, Dahlia, Echinacea, Gaillardia, Heuchera, Hydrangea, Mentha, Papaver, Phlox, Rudbeckia, Salvia, and Veronica

Achilea, Aster, Chrysanthemum, Dahlia, Rudbeckia, Salvia, Solidago and Veronica

Look for brown spots on the leaves. Do not confuse with leaf spot disease. Look for yellowish green adults with four longitudinal black lines that hide under leaves.

Look for brown, necrotic spots on the foliage. Buds are distorted. Tap foliage over white sheet of paper.

Eliminate weeds.

Natural enemies

Big-eyed bugs, damsel bugs and spiders can help reduce populations.

Chemical Options  

Azatin, Ornazin (azadirchtin) (nymphs)

Insecticidal Soap (I.S. 4952CF, M-Pede)

Orthene (acephate)

  Key Diseases

Key Plants

Monitoring

Cultural Management

Botrytis Blight (G, N, L)

Botrytis cinerea, B. elliptica, B. paeoniae

Wide host range. Peonies and Asiatic Lilies especially susceptible.

Look for leaf spots, blights, stem cankers and die back. Powdery gray "mold” may be seen on affected tissues during humid conditions. Look on tender new tissues or wounded tissues.

Remove damaged leaves. Water early in the day so leaves stay as dry as possible.  Provide good air circulation and reduce humidity within the plant canopy.  Use drip irrigation to reduce water splash. 

Bacterial Leaf Spot

 (G, N, L)

Pseudomonas,  Xanthomonas spp.

Aconitum, Coreopsis, Delphinium, Geranium, Heuchera, Heucherella,  Iris, and Papaver

Look for spots on foliage that are dark brown to black in color and appear water-soaked.

Remove damaged leaves when plants are not wet.  Discard severely infected plants and avoid contact with healthy plants. Water early in the day so leaves stay as dry as possible.  Use drip irrigation to reduce water splash. Proper plant spacing will reduce humid conditions within the plant canopy.

Fungal Leaf Spots 

(G, N, L)

 Alternaria, Ascochyta, Cercospora, Didymella

Phyllostrica, Septoria

Aquilegia, Alcea, Aster, Aegopodium, Chrysanthemum, Clematis,  Delphinium, Eupatorium, Heuchera, Hibiscus, Hypericum, Iris, Liatris Lychnis, Monarda, Paeonia, Phlox, Rudbeckia, Veronica, and Viola.  

Look for leaf spots on the  foliage. With a hand lens look for fruiting bodies (spores) on the foliage.

Remove damaged leaves when plants are not wet. Water early in the day. Use drip irrigation. Space plants to provide good air circulation. Propagate from clean stock plants. Clean up diseased leaves in the fall.

Anthracnose  Diseases

(G, N, L)  

Collectrichum sp.

Bergenia, Heucera, Hosta, Lupinus, Rudbeckia, Sedum, Tiarella, and Tricyrtis

Rapid blighting of leaves and stems can occur during favorable conditions. On Lupinus, look for leaf spots on foliage, wilting and stem cankers. Severe plant losses can occur. On Hosta, look for large, irregularly shaped tan spots. Leaves may have a tattered appearance as brown tissue drops out of leaves.

Lupine Anthracnose is seed borne. Rogue diseased plants promptly. Avoid overhead watering and splashing water. Provide good air circulation between plants. Remove diseased foliage and stems in the fall.

Some types of lupine are more resistant to anthracnose.

Downy Mildew (G, N, L)

Peronospora spp.  

Aster, Artemisia, Centaurea, Coreopsis, Geranium, Geum, Helleborus, Lamium, Lupinus, Potentilla, Rudbeckia, Veronica and Viola

From a distance, downy mildew is easily confused with a nutritional deficiency. Look for pale green or yellow patches on the upper leaf surface on Geum and purplish discoloration on Lamium and Veronica. Fuzzy white, tan or gray sporulation occurs on the lower leaf surfaces during conditions of high humidity.

Avoid overwatering. Keep leaves as dry as possible. Space plants to provide good air circulation. Grow plants in full sun, if possible.

Nematodes - Foliar

(G, N)

Aphelenchoides spp.

Anemone, Aquilegia, Baptisia, Bergenia, Chrysanthemum, Ferns, Fragaria, Hepatica, Heuchera, Hosta, Hypericum, Iris, Lamium, Ligularia, Lilium, Malva, Paeonia, Papaver, Phlox, Polygonatum, Salvia, Tricyrtis and others

Infested leaves are off-color, often turning purple or brown with a distinct margin, as the nematodes cannot move through the leaf veins.  Injury from foliar nematodes can be confused with insect feeding, and  fungal or bacterial diseases.

Remove diseased plants or leaves. (Do not place in compost pile, as nematodes can survive in dried and dead plant leaves).  Reduce overhead irrigation to minimize spread.

Chemical Options

Pylon (G)

Powdery Mildew 

(G, N, L)

Erysiphe sp. Sphaerotheca sp.

Aquilegia, Aster, Coreopsis, Clematis, Delphinium, Helianthus, Monarda, Phlox, Pulmonaria, Rudbeckia, Salvia, Scabiosa, Solidago, Sedum, Verbena and Viola

Inspect upper and lower surfaces of leaves for white, powdery fungal growth. On Sedum, powdery mildew resembles a leaf spot disease and not powdery mildew because the infected areas are brown rather than white.

Use proper plant spacing to increase air movement.  Remove infected leaves and stems in the fall. Use resistant varieties whenever possible.

Monarda: Colrain Red, Jacob Cline, Marshall’s Delight, Raspberry Wine, Rose Queen, Rosy Purple, Blue Stocking, Violet Queen

Phlox: Katherine, David, Bright Eyes, Franz Schubert, Orange Perfection, Prime Minister, Starfire

Milstop (potassium bicarbonate)

Ultra-fine oil (horticultural oil)

Rust Diseases (G, N, L)

Puccinia sp.

Aconitum, Adenophora, Alcea, Anemone, Aquilegia, Aster, Calamagrostis, Campanula, Clematis, Delphinium, Hemerocallis, Iris, Liatris, Miscanthus, Malva, Monarda, Lupinus, and Pennisetum

Look for yellow leaf spots on the upper leaf surface. Turn over the leaf to look for orange to reddish brown pustules on the lower leaf surface.

For images of Daylily Rust

See: Daylily Rust Information Page www.ncf.ca/~ah748/rust.html

Remove damaged leaves when plants are dry. Water early in the day. Provide good air circulation around plants. Eliminate alternate host (if there is one). Take cuttings from clean stock plants.  Cut back diseased foliage in the fall. Use resistant varieties. Resistant daylily cultivars include: Prairie Blue Eyes, Carolyn Criswell, Mardi Gras Parade, Woodside Ruby, Hush Little Baby, Follow Your Heart, Chicago Apache, Buttered Popcorn, Green Flutter, Plum Perfect, Frankly Scarlet, Mama Cha Cha, Chinese Scholar and Charlie Pierce Memorial.  Moderately resistant: Stella de Oro

Daylily Leaf Streak

(N, L)

Aureobasidium microstictum 

Hemerocallis

Look for central yellow streak on leaves along midvein. Small, reddish brown flecks and brown spots develop on infected tissue.

Water early in the day. In small plantings, remove affected leaves and leaf residues.