an upgraded and comprehensive list of diseases that affect flowers

Here is an upgraded and comprehensive list of diseases that affect flowers, including stamens (anthers) and pistils (stigma/style/ovary), with scientific details:

🌸 1. Fungal Diseases Affecting Petals, Stamens, Pistils

Botrytis Blossom Blight (Gray Mold)

• Pathogens: Botrytis cinerea, B. elliptica

• Hosts: Plums, roses, lilies, petunias, etc.

• Symptoms: Light-brown necrotic lesions on petals → stamens & pistils browning, fuzzy gray mold development researchgate.net+12apsjournals.apsnet.org+12academic.oup.com+12gardentech.com+1en.wikipedia.org+1

• Conditions Favoring: Cool temperatures (15–20 °C), high humidity, poor airflow

• Impact: Flower abortion, reduced fertility, necrosis of reproductive organs

• Management: Remove infected blooms, increase ventilation, apply chlorothalonil or copper-based fungicides for prevention

Narcissus Fire

• Pathogen: Botryotinia polyblastis

• Hosts: Daffodils (Narcissus spp.)

• Symptoms: Water-soaked, browning petals, wilted flowers; can spread to leaves pmc.ncbi.nlm.nih.gov+2researchgate.net+2plantpathology.ca.uky.edu+2gardentech.com+2hort.extension.wisc.edu+2publications.gc.ca+2en.wikipedia.org+9en.wikipedia.org+9plantpathology.ca.uky.edu+9

• Conditions: Cool, wet spring

• Impact: Flower death, corm health compromised

• Management: Avoid irrigation on flowers, sanitize pruning tools, apply fungicides before bloom

Ovulinia Petal Blight (Azalea Flower Blight)

• Pathogen: Ovulinia azaleae

• Hosts: Azaleas, rhododendrons

• Symptoms: Slimy tan petals on bloom/stamens/pistils; black sclerotia on blooms en.wikipedia.org+11en.wikipedia.org+11content.ces.ncsu.edu+11hort.extension.wisc.edu+1en.wikipedia.org+1sciencedirect.com+4apsnet.org+4academic.oup.com+4

• Conditions: Cool, moist spring

• Impact: Complete bloom collapse

• Management: Remove fallen blooms, apply fungicide just before bloom, improve airflow

Stamen Blight (on Rubus spp.)

• Pathogen: Hapalosphaeria deformans

• Hosts: Raspberry/blackberry

• Symptoms: Swollen petals, white fungal growth on stamens, impaired pollen release

• Impact: Reduced pollination, poor fruit set

• Management: Remove affected canes; prune pre-flower

Carnation Blight

• Pathogen: Alternaria dianthi

• Hosts: Carnation (Dianthus caryophyllus)

• Symptoms: Brown/yellow round spots on petals and flower base; undeveloped stamens apsnet.org+15en.wikipedia.org+15plantpathology.ca.uky.edu+15plantpathology.ca.uky.edupmc.ncbi.nlm.nih.govgardentech.com

• Management: Apply difenoconazole or mancozeb; maintain low humidity in greenhouse

Flower Smut (False Smut of Rice)

• Pathogen: Ustilaginoidea virens

• Hosts: Rice

• Symptoms: Reproductive organ (pistil) hypertrophy; flowers replaced by spore masses apsjournals.apsnet.org

• Management: Fungicide sprays at anthesis, and good sanitation practices

Anther Smut (e.g., on Silene latifolia)

• Pathogens: Microbotryum violaceum, M. silenes-dioicae

• Hosts: Silene spp., Caryophyllaceae family

• Symptoms: Stamens filled with spores instead of pollen; flowers act as pathogen spore vessels plantpathology.ca.uky.edu+8en.wikipedia.org+8en.wikipedia.org+8

• Impact: Sterilizes host, reduces seed production

• Management: Remove infected plants; no chemically resistant options

🦠 2. Bacterial Diseases in Reproductive Structures

Bacterial Shot Hole / Canker

• Pathogen: Pseudomonas syringae pv. syringae/morsprunorum

• Hosts: Cherry, apricot, plum, ornamental Prunus

• Symptoms: Necrotic spots, holes in petals → exudate and stamen/pistil infection

• Conditions: Cool, wet spring

• Impact: Flower deformities, reduced fertility

• Management: Copper sprays in dormancy, sanitize pruning equipment

Bacterial Wilt of Carnation

• Pathogen: Paraburkholderia caryophylli

• Hosts: Carnations

• Symptoms: Stem cracks at the flower base, flower collapse, withered stamens

• Conditions: Warm, high-humidity greenhouses

• Impact: Flower bud mortality

• Management: Use pathogen-free stock, sterilize tools; no chemical cure available

🧬 3. Phytoplasma / Viral Flower Disorders

Phyllody / Floral Virescence

• Pathogens: Phytoplasma (e.g., Aster Yellows) or certain viruses

• Hosts: Aster, rose, citrus, others

• Symptoms: Conversion of petals, stamens, pistils into leafy tissue; sterile or malformed flowers apsjournals.apsnet.org+1pubmed.ncbi.nlm.nih.gov+1missouribotanicalgarden.orgpublications.gc.ca+2researchgate.net+2pmc.ncbi.nlm.nih.gov+2en.wikipedia.org

• Impact: No pollen/ovules; zero fruit set

• Management: Remove infected plants, insect vector control, resistant strains

Pistil Smut (in Buffalograss)

• Pathogen: Salmacisia buchloeana (formerly Tilletia) pubmed.ncbi.nlm.nih.gov+1researchgate.net+1

• Hosts: Buffalograss

• Symptoms: Male flowers develop pistils; pistils filled with fungal spores; stamens in females become enlarged

• Impact: Induced hermaphroditism; complete sterilization of infected flowers

• Management: Remove infected plants; no chemical treatment exists

🛡️ Summary Table

✅ Management Highlights

1. Prompt Removal of infected blooms and stems

2. Maintain airflow and avoid moisture on flowers

3. Apply appropriate fungicides/bactericides before or at early bloom

4. Sterilize tools between pruning/grafting

5. Use disease-resistant varieties where available

6. Remove and isolate infected plants to break disease cycles

7. Control insect vectors especially for phytoplasma viruses