Scouting for Key Diseases on Key Ornamental Plants | Integrated Pest Management | College of Agriculture, Health and Natural Resources

Key plants

Are those specific plant species or cultivars that may be infested with key diseases every year. This varies from location to location and from year to year. Specific cultivars may be more susceptible than others. Here is a list that I gathered from references listed at the end of this fact sheet plus personal observations. It is helpful to develop your own list based upon your own experience and observations.

A few key diseases include: Aster Yellows, Bacterial Leaf Spots and Blights, Black Root Rot, Botrytis Blight, Downy Mildew, Foliar Nematodes, Fungal Leaf Spots, Pythium root and crown rots, Powdery Mildew, Rusts, and Viruses.

Aster Yellows

Key bedding plants affected

Annual Vinca (Catharanthus), Calendula, China Aster, Chrysanthemum, Cosmos, Marigold, and Zinnia

Key herbaceous perennials affected

Aconitum, Bellis, Campanula, Chrysanthemum, Coreopsis, Delphinium, Echinacea, Gaillardia, Monarda, Rudbeckia and Salvia

Bacterial Leaf Spots and Blights

Key bedding plants affected

Matthiola, Florist geranium, Ranunculus, and Zinnia

Key bedding plants affected

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

Black Root Rot

Key bedding plants affected

Annual vinca (Catharanthus), Calibrachoa (million belles), Pansy, Petunia, Salvia, Verbena, and Viola

Key herbaceous perennials affected

Dicentra, hardy geraniums, Heuchera, Creeping and Garden Phlox.

Botrytis Blight

Key bedding plants affected

Annual vinca (Catharanthus), Calibrachoa (million belles), Begonia, Carnation, Chrysanthemum, Cyclamen, Florist Geranium, Impatiens, Marigold, Petunia, Primrose and Zinnia.

Key herbaceous perennials affected

Arabis, Campanula, Echinacea, Heuchera, Hosta, Liatris, Myosotis, Primula and Viola. Peonies and Asiatic lilies
especially susceptible.

Downy mildew

Key bedding plants affected

Alyssum, Argyranthemum, Basil, Coleus, Impatiens, Osteospermum, Pansy, Primula, Rosemary, Salvia, Snapdragon,
Viola, and Verbena

Key herbaceous perennials affected

Agastache, Aster, Artemisia, Buddleia, Coreopsis, Delphinum, Geranium, Geum, Iberis, Lamium, Lupinus, Potentilla,
Rudbeckia, (Goldsturm esp.), Veronica and Viola

Foliar Nematodes

Key bedding plants affected

Ageratum, Begonia, Basil, Chrysanthemum, Coleus, Dahlia, English daisy, Marigold, Primrose, Salvia, Snapdragon, Torenia, Verbena and Zinnia

Key herbaceous perennials affected

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

Fungal Leaf Spots

Key bedding plants affected

Annual vinca (Catharanthus), Dianthus, Impatiens, Marigold, New Guinea impatiens, Florist Geranium, Pansy, Salvia,
and Zinnia

Key herbaceous perennials affected

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

Pythium root and crown rots

Key bedding plants affected

Annual Vinca (Catharanthus), Begonia, Calibroachoa, Chrysanthemum, Dahlia, Gerbera Daisy, Impatiens, Florist geranium, New Guinea impatiens, Primrose, and Snapdragon

Key herbaceous perennials affected

Helleborus, Leucanthemum, and Sidalcea

Powdery Mildew

Key bedding plants affected

Begonia, Calibroachoa (millon belles), Dahlia, Gerbera Daisy, Petunia, Torenia, Salvia, Snapdragon, Verbena, and Zinnia

Key herbaceous perennials affected

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

Rusts

Key bedding plants affected

Chrysanthemum, Fuchsia, Florist Geranium, Salvia, and Snapdragon

Key herbaceous perennials affected

Aconitum, Adenophora, Alcea, Anemone, Aquilegia, Aster, Calamagrostis, Campanula, Clematis, Delphinium, Hemerocallis, Heuchera, Iris, Liatris, Miscanthus, Monarda, Lupinus, Panicum, Pennisetum, Solidago, Veronica, and Viola

Viruses

Cucumber Mosaic Virus (CMV)

Ajuga, Aquilegia, Campanula, Delphinium, Dahlia, Lily, Petunia and Phlox.

Hosta Virus X (HVX)

Hosta, some more susceptible hosta cultivars include Gold Edger, Gold Standard, Golden Tiara, and Sum and Substance

Tomato Spotted Wilt Virus/ Impatiens necrotic spot virus

Key Bedding Plants affected

Begonia, Campanula, Cyclamen, Garden Impatiens, New Guinea impatiens, Pepper, Phlox, Primula, and Tomato

Key herbaceous perennials affected

Centranthus, Hosta, Penstemon, Primula, and Trictytis

Tobacco mottle virus

Key Bedding Plants affected

Calibrachoa, Gerbera Daisy, Impatiens, New Guinea impatiens, Nicotiana, Pepper, Petunia, Tomato and Torenia.

Tobacco rattle virus

Key herbaceous perennials affected

Anemone, Hosta, Peony, and Epimedium

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contained are based on the best available knowledge at the time of publication. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. UConn Extension does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available. The University of Connecticut, UConn Extension, College of Agriculture, Health and Natural Resources is an equal opportunity program provider and employer.