University of Kentucky College of Agriculture, Food & Environment Extension Plant Pathology

College of Agriculture, Food and Environment Cooperative Extension Service

Plant Pathology Fact Sheet PPFS-OR-H-01 Managing Diseases of Herbaceous Ornamentals

Nicole Ward Gauthier Jay Hettmansperger Extension Plant Pathologist County Extension Agent

This guide provides suggestions for symptom Regardless of the cause, affected plants may display recognition and management approaches to one or more of the following symptoms: common diseases of herbaceous plants in residential � blight � scorch and commercial plantings. � dieback � stem/root decay � distortion � stunted growth Disease Identification � galls � wilt Herbaceous landscape ornamentals can succumb � leaf spots � yellowing/discoloration to various adverse factors, including infectious and non-infectious diseases. Infectious diseases are In order to determine the proper course of action for caused by microorganisms, such as fungi, fungus- treatment, it is essential to accurately identify the like water molds, bacteria, nematodes, viruses, and specific cause(s). For assistance with diagnosis, refer phytoplasmas. Abiotic or non-infectious diseases to the resources listed at the end of this publication may be attributed to unfavorable growing conditions, and/or contact your county Extension agent. which can include nutritional deficiencies, improper soil pH, extreme temperatures, excessive soil moisture, or drought. Minnesota.gov

Agriculture & Natural Resources • Family & Consumer Sciences • 4-H/Youth Development • Community & Economic Development Disease Management � Pruned plant parts, fallen leaves, and culled Management of plant diseases in the landscape, plants should be removed from the growing site nursery, and greenhouse usually involves a and destroyed. combination of cultural practices. Fungicides are � Do not compost diseased plant material or soil sometimes warranted, but the following cultural because incomplete composting may result in the management practices should be adopted regardless survival of disease propagules. of fungicide program (whether no-spray, low-spray, � Equipment, such as pruners, trowels, shovels, organic, or conventional). and containers should be disinfested after they come into contact with diseased plant material Exclusion or infested soil, especially when bacterial, Avoid introduction of pathogens into a planting: phytoplasma, and viral pathogens may be present. � Purchase and plant only healthy material Bleach (10% solution), rubbing alcohol (70%), or a (transplants, seeds, and bulbs). commercial greenhouse sanitizer can be used to � Carefully examine foliage, stems, roots, and disinfest tools; rinse tools before storing to help bulbs for symptoms of disease or presence of prevent corrosion. pathogenic propagules prior to planting. � Small quantities of soil can be sterilized using � Reject plant material appearing unthrifty or steam, a dry oven, or a microwave. showing disease symptoms. Crop rotation Planting and cultural practices Some soilborne pathogens (Phytophthora, Fusarium, Following good cultural practices can aid in disease Rhizoctonia, Sclerotinia, etc.) can build-up and prevention. survive for long periods (in some cases, for many years) in soils. Rotate to tolerant or resistant plant � Select plant species and cultivars tolerant to species or cultivars. local heat and cold extremes. � Use disease resistant or tolerant cultivars whenever possible, especially if there is a history Fungicides of disease. Plants can be protected from disease using fungicides, bactericides, and/or nematicides; they are used as � Provide adequate spacing to allow for air preventatives. Once plants are infected, fungicides circulation, taking into consideration plant size at will not cure diseased plants. full maturity. Poor air circulation can result in high � humidity within plant canopies, prolonged leaf Check product label to be sure both host and wetness, and soggy soils that can be conducive to disease are listed; apply only as directed on the disease development and pathogen spread. label. � � Maintain plant vigor by promoting plant health; Managing insects that vector disease (e.g. this will enable plants to better resist diseases leafhopper, aphids, and thrips) with insecticides and stress-related problems. Water plants during can be effective in some instances. drought, fertilize according to soil test results, � Commercial greenhouses should consider and mulch (where applicable) to maintain soil applying fungicides to nearby healthy plants moisture and regulate soil temperatures. once disease is detected and managed. � Contact a local county Extension agent for Sanitation current pesticide recommendations. Elimination (removal and destruction) of diseased plants and plant material reduces the source of inoculum by reducing the number of propagules (fungal spores, bacterial cells, and virus particles) that can initiate disease. Sanitation minimizes the spread of disease to healthy plants and removes overwintering structures that infect in spring. (Refer to Landscape Sanitation, PPFS-GEN-04) Leaf, Bud, Flower, and Stem Diseases Disease/ hosts Cause Symptoms Management Bacterial Bud rot Canna Xanthomonas Leaves blacken as they ▪ Select rootstocks from healthy plants. cannae unfold. Stem and flower ▪ Avoid overhead irrigation. buds may decay. ▪ Do not crowd plants; provide adequate spacing for air circulation, and thin plants as they mature. ▪ Rogue symptomatic plants. ▪ Use recommended bactericides. Leaf spots Iris Xanthomonas Water-soaked spots form on ▪ Remove and destroy infected plant tardicrewscens leaves; spots may develop parts. into brown streaks. ▪ Maintain dry foliage and buds; avoid Mum/ Pseudomonas Small dark brown to black overhead irrigation. Chrysanthemum cichorii spots appear first on lower ▪ Thin plants to improve air circulation. leaves; spots become ▪ To avoid spreading bacterial inoculum, irregular as they enlarge. never work with wet plants. Disease may spread up on ▪ Do not plant or propagate infected plant just one side of the plant. material. Flowers may also become ▪ Fixed copper sprays may help protect infected. healthy plants. Zinnia Xanthomonas Small brown spots campestris surrounded by yellow halos appear on leaves. John Hartman, UK John Hartman, UK John Hartman,

Bacterial leaf spot on mum (chrysanthemum) Leaf, Bud, Flower, and Stem Diseases Disease/ hosts Cause Symptoms Management Bacterial Leaf spot & stem canker English ivy Xanthomonas Watersoaked spots that ▪ Practice sanitation throughout the campestris become dark brown and growing season; prune, clean-up, and angular form on leaves; destroy plant debris as symptoms petioles and stems turn black develop, especially in autumn. and die. ▪ Provide adequate spacing for air Stem rot, leaf spot & blight circulation. ▪ Maintain dry foliage; avoid overhead Geranium Xanthomonas Initially irregular-shaped watering. pelargonii spots develop on leaves. ▪ Use disease-resistant cultivars when Wilting of leaf margins available. Replace susceptible plant results in formation of material with tolerant species/cultivars yellow or tan V-shaped when appropriate. lesions with dark leaf veins; lesions expand to kill larger areas of leaves. Stems appear blackened and may decay, causing leaf yellowing and wilt. Cheryl Kaiser, UK Cheryl John Hartman, UK John Hartman, Cheryl Kaiser, UK Cheryl

Bacterial leaf spot and blight (geranium) Leaf, Bud, Flower, and Stem Diseases Disease/ hosts Cause Symptoms Management Fungal Anthracnose Daylily, dianthus, Colletotrichum Large irregular spots (white ▪ Practice sanitation throughout the hosta, ivy, spp., Gloeosporium to tan with darker borders) growing season; prune, clean-up, and liriope, peony, spp. develop on foliage; cankers destroy plant debris as symptoms phlox, vinca, and or sunken lesions can form develop, especially in autumn. others on leaf and flower stems, ▪ Provide adequate spacing for air resulting in dieback. circulation. ▪ Maintain dry foliage; avoid overhead Leaf spots; Leaf blotches watering. General (many Alternaria spp., Fungal leaf spots occur on ▪ Use disease-resistant cultivars when hosts) Ascochyta spp., many hosts as tan or brown available. Replace susceptible plant Cercospora spp., circular to irregular spots; material with tolerant species/cultivars Cladosporium spp., spots may expand to when appropriate. Corynespora spp., encompass large portions of ▪ Apply fungicides as needed to protect Septoria spp., leaves. Some fungal spots new growth. may have a darker margin. -- Once plants are infected, fungicides will not cure disease. -- Remove diseased plant parts and thin plants as needed before applying fungicides. -- When applying fungicide to plants with waxy foliage, a wetting agent (adjuvant/surfactant) can be added so sprays adhere to foliage. -- Check fungicide label to be sure both host and pathogen are listed. Paul Bachi, UK Bachi, Paul Paul Bachi, UK Bachi, Paul RK Jones, NC State University, Bugwood.org University, NC State RK Jones,

Anthracnose (Lirope, left; Peony, above) Leaf, Bud, Flower, and Stem Diseases Disease/ hosts Cause Symptoms Management Fungal Leaf spots; Leaf blotches (cont'd) English ivy Phyllosticta spp. Brown, circular to irregular ▪ Practice sanitation throughout the spots develop on leaves. growing season; prune, clean-up, and Iris Mycosphaerella Small, brown leaf spots with destroy plant debris as symptoms macrospora gray centers develop; may develop, especially in autumn. (Didymellina be surrounded by a water- ▪ Provide adequate spacing for air macrospora); soaked margin. As spots circulation. Heterosporium spp. enlarge, leaves becomes ▪ Maintain dry foliage; avoid overhead blighted. watering. Mum/ Alternaria spp., Small, dark brown spots ▪ Use disease-resistant cultivars when Chrysanthemum Cercospora spp., appear first on lower leaves. available. Replace susceptible plant Septoria spp. Leaves may become material with tolerant species/cultivars blighted, shrivel, and die. when appropriate. Dead leaves may hang on ▪ Apply fungicides as needed to protect diseased plants. new growth. -- Once plants are infected, fungicides Zinnia Alternaria zinniae Circular to irregular purple- will not cure disease. brown spots develop on -- Remove diseased plant parts and thin foliage; spots may have gray plants as needed before applying centers. Severe infection fungicides. results in leaf blight. Stem -- When applying fungicide to plants infections can lead to plant with waxy foliage, a wetting agent death. (adjuvant/surfactant) can be added so sprays adhere to foliage. -- Check fungicide label to be sure both host and pathogen are listed. John Hartman, UK John Hartman, Consumer Services, Bugwood.org Services, Consumer

Alternaria leaf spot (Zinnia, left); Septoria leaf spot (mum/ FL Division of Plant Industry, FL Dept. of Agriculture & of Agriculture FL Dept. FL Division of Plant Industry, chrysanthemum, right) Leaf, Bud, Flower, and Stem Diseases Disease/ hosts Cause Symptoms Management Fungal Powdery mildew Many plants, Erysiphe spp., White, powdery spots ▪ Practice sanitation throughout the especially aster, Golovinomyces appear on upper leaf growing season; prune, clean-up, and begonia, dahlia, spp., Oidium spp., surfaces and stems; white destroy plant debris as symptoms mum, peony, and others fungal growth may develop, especially in autumn. petunia, phlox, eventually cover entire leaf ▪ Provide adequate spacing for air rudbeckia, shasta surfaces. Older leaves are circulation. daisy, spirea, generally affected first. ▪ Maintain dry foliage; avoid overhead yarrow, and watering. zinnia ▪ Use disease-resistant cultivars when available. Replace susceptible plant Red spot material with tolerant species/cultivars Peony Cladosporium Glossy, dark purple spots when appropriate. paeoniae appear on upper leaf ▪ Apply fungicides as needed to protect surfaces during moist new growth. weather; spots on the under -- Once plants are infected, fungicides surface are brown. Reddish will not cure disease. lesions may also develop on -- Remove diseased plant parts and thin stems and petioles. plants as needed before applying fungicides. -- When applying fungicide to plants with waxy foliage, a wetting agent (adjuvant/surfactant) can be added so sprays adhere to foliage. -- Check fungicide label to be sure both host and pathogen are listed. Sheryl Pirone Sheryl John Hartman, UK John Hartman,

Powdery mildew (zinnia, left; phlox, right) Leaf, Bud, Flower, and Stem Diseases Disease/ hosts Cause Symptoms Management Fungal Rust Aster, Puccinia spp., Reddish-brown powdery ▪ Practice sanitation throughout the delphinium, iris, Coleosporium spp. pustules form on leaves, growing season; prune, clean-up, and daisy, daylily, stems, and seed pods. destroy plant debris as symptoms hollyhock, Leaves turn brown and die develop, especially in autumn. snapdragon, and when infections are ▪ Provide adequate spacing for air others numerous. circulation. ▪ Maintain dry foliage; avoid overhead Zonal rust watering. Geranium Puccinia pelargonii- Reddish-brown lesions ▪ Use disease-resistant cultivars when zonalis appear in circular patterns available. Replace susceptible plant on foliage. Dusty reddish material with tolerant species/cultivars spores can be brushed from when appropriate. spots. Leaves yellow, dry, ▪ Apply fungicides as needed to protect and drop prematurely. new growth. -- Once plants are infected, fungicides will not cure disease. -- Remove diseased plant parts and thin plants as needed before applying fungicides. -- When applying fungicide to plants with waxy foliage, a wetting agent (adjuvant/surfactant) can be added so sprays adhere to foliage. -- Check fungicide label to be sure both host and pathogen are listed. Paul Bachi, UK Bachi, Paul Sandra Jensen, Cornell University, Bugwood.org University, Jensen, Cornell Sandra

Zonal rust (geranium, left); Rust (hollyhock, right) Leaf, Bud, Flower, and Stem Diseases Disease/ hosts Cause Symptoms Management Fungal Botrytis blight/Gray mold Many plants, Botrytis cinerea Dead blotches appear on ▪ Practice sanitation throughout the including leaves, flowers, and stems. growing season; prune, clean-up, and begonia, Stems may rot causing plants destroy plant debris as symptoms geranium, lily, collapse. Flower buds may develop, especially in autumn. marigold, peony, fail to open; diseased flowers ▪ Provide adequate spacing for air periwinkle, that open become decayed circulation. petunia, and drop prematurely. ▪ Maintain dry foliage; avoid overhead snapdragon, Affected plant tissues may watering. tulip, and zinnia be covered with gray fuzzy ▪ Use disease-resistant cultivars when fungal growth and spores. available. Replace susceptible plant material with tolerant species/cultivars Leaf & stem blight when appropriate. Pachysandra Volutella Brown blotches appear on ▪ Apply fungicides as needed to protect pachysandricola leaves; dark cankers may new growth. form on stems. Leaves die -- Once plants are infected, fungicides as foliar blotches expand and will not cure disease. cankers girdle stems. -- Remove diseased plant parts and thin plants as needed before applying fungicides. -- When applying fungicide to plants with waxy foliage, a wetting agent (adjuvant/surfactant) can be added so sprays adhere to foliage. John Hartman, UK John Hartman, -- Check fungicide label to be sure both host and pathogen are listed. MC Shurtleff, University of IL, Bugwood.org University MC Shurtleff, John Hartman, UK John Hartman, Volutella leaf and stem blight in planting (pachysandra, top left) and close-up of Volutella stolon lesions (lower left); Botrytis blight/gray mold (marigold, above) Leaf, Bud, Flower, and Stem Diseases Disease/ hosts Cause Symptoms Management Fungal Web blight/Rhizoctonia aerial blight Boston fern, Rhizoctonia solani Brown, dried lesions appear ▪ Completely remove and destroy mum, pansy, on leaves; these spread to infected plants. periwinkle, vinca, involve large portions of ▪ Plant only healthy planting material. etc. leaves. Under humid ▪ Do not crowd plants; provide adequate conditions, a fine webbing of spacing for air circulation, and thin plants fungal mycelia covers as they mature. blighted portions of plants. ▪ Protectant fungicides can be used in commercial plantings. Water molds (Fungus-like organisms; Oomycetes) Phytophthora aerial blight Pansy, vinca Phytophthora spp. Irregularly-shaped, ▪ Remove and destroy infected plants watersoaked, light brown promptly. spots develop on leaves. ▪ Avoid overhead irrigation. Disease can spread rapidly ▪ Do not crowd plants; provide adequate over large portions of plants. spacing for air circulation, and thin plants Once stems are girdled, plant as they mature. death follows. Nicole Ward Gauthier, UK Gauthier, Ward Nicole Nicole Ward Gauthier, UK Gauthier, Ward Nicole

Web blight (mum/chrysanthemum, left) and close-up of Rhizoctonia fungal strands (right) Leaf, Bud, Flower, and Stem Diseases Disease/ hosts Cause Symptoms Management Nematodes Foliar Manynematodes plants, Aphelenchoides Areas bounded by veins turn ▪ Do not introduce infected plants into including spp. brown and die, forming a planting site. anemone, coral- patchwork or long streaks of ▪ Remove and destroy diseased plants. bells, geranium, dead tissue on leaves. ▪ Chemical treatment is available for hosta, iris, commercial use. peony, and phlox Elizabeth Bush, Virginia Tech, Bugwood.org Tech, Bush, Virginia Elizabeth NC State University, Plant Pathology Archive, Bugwood.org Bugwood.org Archive, Plant Pathology University, NC State

Foliar nematode (coral bells, above; hosta, upper & lower right) NCSU, Plant Pathol0gy Archive, Bugwood.org Bugwood.org Archive, PlantNCSU, Pathol0gy Leaf, Bud, Flower, and Stem Diseases Disease/ hosts Cause Symptoms Management Other Aster yellows (phytoplasma) Aster, cosmos, Aster yellows Leaves become discolored ▪ Plants will not recover; completely coreopsis, phytoplasma (light green, yellow, white, remove and destroy infected plants. echinacea, red or purple) and stunted. ▪ Remove nearby perennial weeds that marigold, mum, Flowers are small and can serve as a source of inoculum. petunia, purple deformed; may never color coneflower, properly. Stems are weak snapdragon, and may form a clump vinca, zinnia, etc. (witches broom). Bud blast (abiotic) Peony Usually due to poor Young buds turn dark, dry ▪ Promote plant vigor by providing good growing conditions up, and fail to open. growing conditions (proper planting, (e.g., potassium fertilization, irrigation, etc.) deficiency, drought, cold spring weather, excess shade, planted too deeply, etc.). Whitney Crenshaw, CO State University, Bugwood.org University, State CO Crenshaw, Whitney Whitney Crenshaw, CO State University, Bugwood.org University, State CO Crenshaw, Whitney

Aster yellows (cosmos, left; marigold, right) Leaf, Bud, Flower, and Stem Diseases Disease/ hosts Cause Symptoms Management Other Mosaic; Ringspot (virus) Columbine, Various viruses, Leaves become mottled with ▪ Remove and destroy infected plants dahlia, gladiolus, including alfalfa dark and light green areas or immediately. petunia, and mosaic virus (AMV), develop yellowish-green ▪ Plant only healthy planting material. others cucumber mosaic ringspots. Plants may be ▪ Control aphid vectors. virus (CMV), dahlia stunted and flowering mosaic virus (DMV), reduced. Gladiolus flowers and tobacco mosaic become abnormally virus (TMV) streaked.

Vascular Wilts and Root, Crown & Lower Stem Diseases Disease/ hosts Cause Symptoms Management Fungal Black root rot Many plants, Thielaviopsis Affected plants are stunted, ▪ Do not introduce diseased plants into including basicola slow growing, and less planting. marigold, pansy vigorous than healthy plants ▪ Infected plants should be removed and (viola), due to decaying roots. destroyed; dig up as much of the rootball periwinkle, Plants wilt and turn yellow as and surrounding soil as possible. petunia, the disease progresses. ▪ Replant site with tolerant/resistant ranunculus, and Brown to black lesions plants or cultivars. zinnia develop on roots; they are in sharp contrast to healthy white roots. & Consumer Protection, Bugwood.org Protection, & Consumer Elizabeth Bush, Virginia Tech, Bugwood.org Tech, Bush, Virginia Elizabeth Anette Phibbs, WI Dept. of Agriculture, Trade Trade of Agriculture, WI Dept. Anette Phibbs, Alfalfa mosaic virus (petunia, left); Black root rot (zinnia, right) Vascular Wilts and Root, Crown & Lower Stem Diseases Disease/ hosts Cause Symptoms Management Fungal Fusarium wilt Astilbe, mum, Fusarium Plants turn yellow, wilt, and ▪ Do not introduce diseased plants into petunia, and oxysporum die. Yellowing and wilting planting site. others may affect only one side of a ▪ Infected plants should be removed and plant; a branch or leaf may destroyed; dig up as much of the rootball also be half yellow, while the and surrounding soil as possible. other half remains green. ▪ Replant site with tolerant/resistant plants or cultivars. Southern stem blight Many plants, Sclerotium rolfsii; S. Plants wilt and die in patches including hosta, delphinii in plant beds. Small, brown phlox and to yellow-brown spherical rudbeckia; on sclerotia may be observed ajuga, this clinging to rotted stems at disease is the base of plants. Sclerotia referred to as are often embedded in white 'ajuga crown rot' fungal mycelium on the stem surface. Cheryl Kaiser, UK Cheryl John Hartman, UK John Hartman,

Ajuga crown rot in ajuga planting (left) and potted plant

(upper right); close-up of sclerotia (lower right) Bugwood.org David Langston, University of GA, University Langston, David Vascular Wilts and Root, Crown & Lower Stem Diseases Disease/ hosts Cause Symptoms Management Fungal White mold/Timber rot Many plants, Sclerotinia spp. Plants collapse following a ▪ Do not introduce diseased plants into including aster, soft, mushy decay at the nurseries or landscapes. begonia, base of stems. Hard, black, ▪ Infected plants should be removed and geranium, liatris, irregular sclerotia resembling destroyed; dig up as much of the rootball peony, petunia, small raisins may be found and surrounding soil as possible. and zinnia inside rotted stems and on ▪ Replant site with tolerant/resistant the ground. plants or cultivars. Rhizoctonia root & stem rot All plants Rhizoctonia solani Seedlings, roots, and lower ▪ Practice sanitation throughout the stems develop brown lesions growing season; prune, clean-up, and and decay. Plant tops yellow destroy plant debris as symptoms and wilt. Wirestem develop, especially in autumn. (constricted, wiry stem) may ▪ Provide adequate spacing for air develop, especially in older circulation. plants. ▪ Maintain dry foliage; avoid overhead watering. ▪ Use disease-resistant cultivars when available. Replace susceptible plant material with tolerant species/cultivars when appropriate. Kenny Seebold, Uk Kenny Seebold, Bugwood.org Jody Fetzer, MD Capital & Planning Commission, Bugwood.org Bugwood.org & Planning Commission, MD Capital Fetzer, Jody RK Jones, NC State University, University, NC State RK Jones,

White mold (zinnia, left), close-up of sclertium (upper right), and Rhizoctonia stem rot (petunia, lower right) Vascular Wilts and Root, Crown & Lower Stem Diseases Disease/ hosts Cause Symptoms Management Fungal Stem canker & dieback Periwinkle Phoma exigua Dark, brown-to-black lesions ▪ Practice sanitation throughout the (vinca) girdle lower stems and growing season; prune, clean-up, and shoots. Foliage and stems destroy plant debris as symptoms wilt and die. develop, especially in autumn. ▪ Provide adequate spacing for air circulation. ▪ Maintain dry foliage; avoid overhead watering. ▪ Use disease-resistant cultivars when available. Replace susceptible plant material with tolerant species/cultivars when appropriate. ▪ Apply fungicides as needed to protect new growth. -- Once plants are infected, fungicides will not cure disease. -- Remove diseased plant parts and thin plants as needed before applying fungicides. -- Check fungicide label to be sure the host and pathogen are listed. Elizabeth Bush, Virginia Tech, Bugwood.org Tech, Bush, Virginia Elizabeth Bruce Watt, University of Maine, Bugwood.org University Bruce Watt,

Stem canker & dieback (periwinkle/ vinca) in planting (left) and close- up of diseased stem (right) Vascular Wilts and Root, Crown & Lower Stem Diseases Disease/ hosts Cause Symptoms Management Water molds (Fungus-like organisms; Oomycetes) Root, stem & crown rots All plants Pythium spp., Roots, lower stems, and/or ▪ Improve surface and subsoil drainage. Phytophthora spp. crown decay. Plant tops ▪ Once plants are infected, they cannot be yellow, wilt, and die back. cured. Remove and destroy diseased plants, as well as root balls and surrounding soil. ▪ Specialized soil drenches may be used to protect nearby healthy plants against infection. Read package label for specific plants that can be treated. Nematodes Root knot nematode Many plants, Meloidogyne spp. Plant growth is stunted, and ▪ Do not introduce diseased plants into including petunia plants decline. Roots have planting site. abnormal swellings or knots. ▪ Once plants are infected, they cannot be cured. Infected plants should be removed and destroyed; dig up as much of the rootball and surrounding soil as possible. ▪ Replant site with tolerant/resistant plants or cultivars. Jeffrey Lotz, FL Dept. of Agriculture & Consumer Services, Bugwood.org Services, & Consumer of Agriculture FL Dept. Lotz, Jeffrey

Root knot nematode (petunia) Bulb, Corm & Rhizome Diseases Disease/ hosts Cause Symptoms Management Bacterial Soft rot Iris Erwinia spp. Leaves may wilt, turn brown ▪ Control insect borers, which create at the tips, and then die. wounds for entry of bacteria. Rhizomes develop a soft, ▪ Remove decayed portions of rhizomes slimy rot. and, when necessary, entire plants. Fungal Basal rot Narcissus Fusarium spp. Basal portion of bulb shows ▪ Avoid injuring bulbs when digging; dry a brown, dry decay. Infected them rapidly before replanting. plants are stunted with ▪ Discard decayed bulbs. yellow leaves. Corm rot Gladiolus Fusarium spp. Brown, sunken, decayed ▪ Avoid injuring corms when digging. areas develop on corms. ▪ Store corms in a dry location that is 35°F to 40F. ▪ Dust corms with a fungicide before planting. RK Jones, NC State University, Bugwood.org University, NC State RK Jones, Dept. of Platn Pathology, NC State University, Bugwood.org University, NC State Pathology, of Platn Dept.

Iris soft rot (left), Fusarium bulb rot (narcissus, upper right), and Fusarium corm rot (gladiolus, lower right) Additional Resources

� Plant Pathology Extension Publications-- � Plant Pathology Extension Publications-- Herbaceous Ornamentals Greenhouse http://plantpathology.ca.uky.edu/extension/publicat http://plantpathology.ca.uky.edu/extension/ ions#HERBACEOUSORNAMENTALS publications#GreenhouseCrops

May 2017 Acknowledgement The authors are grateful to Sladana Bec, University of Florida Plant Diagnostic Center, for her review of this publication. Editor: Cheryl Kaiser, Extension Support Staff Revised from the original fact sheet, Guide for Control of Annual and Perennial Flower and Ground Cover Diseases in landcscapes (ID87), written by John Hartman, Mary Witt, and Cheryl Kaiser

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