Camellia Diseases and Insect Pests in South Carolina

Quick Guide / At-a-Glance

Affected Plants:

• Sasanqua camellia (Camellia sasanqua, C. hiemalis, C. vernalis)
• Japanese camellia (Camellia japonica)

Primary Disease Types:

• Dieback & canker
• Flower blight
• Root rot
• Leaf gall
• Algal leaf spot
• Viral infection

Primary Insect Pests:

• Tea scale (Fiorinia theae)
• Cottony camellia scale (Pulvinaria floccifera)

Primary Causes:

• Fungal pathogens (Glomerella cingulata, Ciborinia camelliae, Phytophthora cinnamomi, Exobasidium camelliae)
• Parasitic alga (Cephaleuros virescens)
• Virus transmission through grafting
• Sap-feeding scale insects

Most Important Prevention Strategy:

• Maintain proper drainage, sanitation, and plant vigor
• Monitor regularly for scale infestations

Chemical Control:

• Fungicides (thiophanate-methyl, copper fungicides, mancozeb, captan, mefenoxam)
• Insecticides (horticultural oil, insecticidal soap, acephate, dinotefuran)
• Apply according to label directions

Camellias are one of the most desirable and well-adapted plants in South Carolina landscapes. Many common problems in sasanqua camellia (Camellia sasanqua, C. hiemalis, and C. vernalis) and the common Japanese camellia (Camellia japonica) can be prevented or minimized by following proper cultural recommendations.

The three most serious camellia diseases in South Carolina are camellia dieback and canker, flower blight, and root rot. The most important insect pest to watch for is tea scale. More information on successfully growing camellias is available in HGIC 1062, Camellia.

Camellia Diseases in South Carolina

Camellia Diseases: Camellia Dieback and Canker on Camellia

Camellia dieback and canker are among the most serious fungal diseases affecting camellias in South Carolina.

Cause

Camellia dieback and canker are caused by the fungus Glomerella cingulata.

Symptoms

• Leaves on affected branches suddenly turn yellow and wilt
• Branch tips usually die back
• Gray blotches appear on the bark and stem
• Sunken areas (cankers) develop and may girdle the stem
• Portions of the plant above the stem canker lose vigor, wilt, and die
• Symptoms worsen during hot, dry weather

Prevention & Treatment

Maintaining healthy camellia plants is the primary defense against dieback and canker.

Cultural Controls

• Plant camellias in well-drained acidic soil
• Avoid wounding stems and branches
• Fertilize properly
• Prune diseased twigs several inches below the affected areas
• Disinfect pruning tools between cuts using one part household bleach to nine parts water

Chemical Control

Fungicides can be applied during wet periods and during normal leaf-drop periods to protect newly formed leaf scars from infection.

• Thiophanate-methyl
• Copper-based fungicides

Apply all chemicals according to directions on the label. See Table 1 for examples of products.

Camellia Diseases: Camellia Flower Blight on Camellia

Camellia flower blight is a serious fungal disease that affects camellia blooms in South Carolina.

Cause

Camellia flower blight is caused by the fungus Ciborinia camelliae and appears in early spring when moisture is present.

Symptoms

• Small, brown, irregular-shaped spots on the flower petals
• Spots enlarge rapidly and may cover most of the flower
• Entire flower turns brown
• Flowers drop within 24 to 48 hours
• Only flowers are affected

Distinguishing features:

• Brown area rapidly spreads toward the center of the flower
• Dark, brown veins in the petals distinguish flower blight from cold injury

Prevention & Treatment

Sanitation is the most effective management strategy for camellia flower blight.

Cultural Controls

• Remove and destroy infected flowers immediately
• Rake up and remove fallen leaves, flowers, and plant debris
• Replace the mulch under the plant
• Apply control measures to nearby camellia plants in the landscape

Note: This fungus survives in the soil, and spores can be wind-borne for up to a mile.

Chemical Control

Fungicide sprays recommended for camellia flowers include:

• Mancozeb (flower spray application)
• Mancozeb or captan (soil drenches every 2 weeks from late December through January)

See Table 1 for product examples. Apply all chemicals according to label directions.

Camellia Diseases: Root Rot on Camellia

Root rot is a destructive fungal disease that affects camellia roots and may lead to plant decline or death in South Carolina.

Cause

Root rot on camellia is caused by the soilborne fungus Phytophthora cinnamomi.

Symptoms

• Uniform leaf yellowing
• Poor growth and general decline
• Wilting of the entire plant
• Loss of small feeder roots
• Infected roots are a red-brown to dark-brown color (healthy roots are white)
• Rapid plant death or long-term gradual decline

Prevention & Treatment

Root rot is difficult to control once infection occurs, so prevention is critical for camellia health.

Cultural Controls

• Choose well-drained planting sites
• Improve drainage using raised beds
• Purchase healthy plants that show no signs of wilting or yellowing of the leaves
• In affected areas, plant Camellia sasanqua cultivars
• Use Camellia japonica cultivars grafted onto a sasanqua rootstock

Resistant Varieties

• All varieties of Camellia sasanqua are resistant
• All varieties of Camellia japonica are susceptible

Chemical Control

Fungicides are preventative only and will not cure infected plants.

• Mefenoxam (Subdue GR)

Repeat applications are required. Due to cost and application accuracy, homeowners may consider hiring a licensed landscaper for soil-applied fungicides. Apply all chemicals according to directions on the label.

Camellia Diseases: Leaf Gall on Camellia

Leaf gall is a fungal disease common on sasanqua camellias and causes abnormal leaf growth in spring.

Cause

Leaf gall is caused by the fungus Exobasidium camelliae.

Symptoms

• Enlarged, thickened and fleshy new shoots and leaves
• Abnormal leaf shape
• Leaf color changes from light green to nearly white or pink
• Galls harden and turn brown over time
• Severe plant damage is uncommon
• Whitish spore mass visible on the undersides of the leaves after galls rupture (sign)

Prevention & Treatment

Remove young galls early to reduce disease pressure the next year.

Cultural Controls

• Remove and destroy young galls before lower leaf surfaces turn white
• Rake up and remove fallen leaves
• Avoid wetting the leaves when watering.
• Reduce humid, moist, shady conditions when possible

Chemical Controls

Chemical controls are only partially effective and must be applied before infection occurs.

• Mancozeb (start sprays at budbreak and continue through the first of June at 7 to 14 day intervals)

See Table 1 for examples of products. Apply all chemicals according to directions on the label.

Camellia Diseases: Camellia Yellow Mottle Virus on Camellia

Camellia yellow mottle virus is a viral disease affecting foliage and flowers and is spread through root grafts and propagation of diseased stock.

Cause

Camellia yellow mottle virus is transmitted through:

• Root grafts
• Propagation of infected plant material

Symptoms

• Irregular, yellow, mottled, or splotchy patterns on leaves
• Leaves may turn entirely yellow
• Irregular white blotches appear on infected flowers

Prevention & Treatment

There is no chemical control for camellia yellow mottle virus.

Cultural Controls

• Plant only virus-free plants from reputable sources

Camellia Diseases: Algal Leaf Spot on Camellia

Algal leaf spot is a disease of camellia foliage caused by a parasitic alga and is common in warm, humid conditions in South Carolina.

Cause

Algal leaf spot on camellia is caused by the parasitic alga Cephaleuros virescens.

Symptoms

• Circular or blotchy spots on leaves
• Slightly raised lesions on leaves
• Wavy or feathered spot margins
• Spots vary from a crusty gray-green to greenish-brown
• Velvety, red-brown appearance in summer during spore production
• Premature yellowing and leaf drop with heavy infestations

Prevention & Treatment

Management focuses on reducing environmental conditions that favor algal growth.

Cultural Controls

• Improve air circulation around plants
• Reduce excess moisture on foliage
• Maintain proper plant spacing
• Promote overall plant vigor

For more information and control measures for algal leaf spot, please see HGIC 2060, Algal Leaf Spot.

Camellia Insect Pests in South Carolina

Camellia Insect Pests: Scale Insects on Camellia

Scale insects are the most common and damaging insect pests of camellia in South Carolina, feeding by piercing plant tissue and sucking sap.

Cause

Scale insects feed on plants by piercing plant tissue and sucking sap. They do not look like typical insects.

• Small and immobile
• No visible legs
• Appearance varies depending on species and sex
• Often resemble small fish scales attached to the plant
• May go unnoticed until populations reach damaging levels

On camellia, scales usually attach to leaves, although some species may also attach to stems.

Heavy infestations weaken plants and may result in:

• Yellowing of upper leaf surfaces
• Fewer and smaller blossoms
• Leaf drop
• Twig dieback
• Plant death

Common Scale Species

Tea scale (Fiorinia theae)

Tea scale is the most serious scale insect on camellia.

• Attaches on the underside of leaves
• Oblong shape with a ridge down the center
• Female about ¹/₂₀-inch long
• Males are about two-thirds the size of the females
• Females dark brown, gray, or nearly black
• Males are white

Reproduction and life cycle:

• Females lay 10 to 16 eggs, which remain protected under their bodies
• Eggs hatch in one to three weeks
• Bright yellow crawlers emerge and disperse

Typical infestation signs and symptoms:

• Yellow splotches on the upper leaf surfaces
• Cottony masses covering leaf undersides during heavy infestations

Cottony camellia scale (Pulvinaria floccifera)

Cottony camellia scale is a soft scale that feeds on camellia, as well as holly, hydrangea, English ivy, euonymus, maple, rhododendron, yew, and pittosporum.

• Adult scale flat and about 1/8-inch in diameter
• Yellowish-tan in color
• Produces large amounts of sugary honeydew
• Honeydew attracts ants and leads to black sooty mold development

Life cycle characteristics:

• Females produce white cottony ovisacs in early summer
• Eggs hatch in summer
• Crawlers (small mobile immatures) move to lower leaf surfaces to feed

Heavy infestations may cause:

• Pale green or yellow foliage
• Sooty mold on leaves

Symptoms

Scale infestations on camellia reduce plant vigor and flowering performance.

General symptoms may include:

• Yellow splotches on upper leaf surfaces
• Pale green or yellow foliage
• Fewer and smaller blossoms
• Leaf drop
• Twig dieback
• Reduced plant vigor
• Black sooty mold on leaves (associated with honeydew production) (sign)
• Cottony egg masses or scale coverings on leaf undersides (sign)

With heavy infestations, long-term decline or plant death may occur.

Prevention & Treatment

Effective control of scale insects on camellia depends on proper timing and targeting the crawler stage.

Cultural Controls

• Scrape off light infestations by hand
• Remove and destroy heavily infested leaves
• Monitor crawler emergence using:
  • Sticky cards
  • Tape wrapped around a branch
  • Place an infested shoot in a sealed bag to observe crawler movement

Encouraging plant vigor reduces susceptibility to severe infestations.

Biological Control

Natural predators and parasites help suppress scale populations. Avoid unnecessary use of broad-spectrum insecticides that may disrupt these beneficial organisms.

Chemical Control

Chemical control is most effective when directed at the crawler stage.

Horticultural Oil

• Apply refined horticultural oil in late winter or early spring. This will kill many adults, crawlers, and eggs by smothering them.
• Use a 2% solution (5 tablespoons of oil per gallon of water)
• Spray thoroughly to run off on leaves, twigs, and stems
• Apply when temperatures will be above 45°F for the next 48 hours
• Do not spray when rain is expected within 24 hours

Do not apply when temperatures exceed 90°F or to drought-stressed plants. Spray late in the day.

Insecticidal Soap

• Apply during crawler activity
• Make two applications 10 days apart
• Spray when the temperatures are between 45 and 90°F
• Apply in the evening to increase effectiveness

Contact Insecticides (Crawler Stage Only)

• Acephate
• Bifenthrin
• Cyfluthrin
• Cyhalothrin
• Malathion
• Permethrin

Acephate may give the best control due to foliar systemic activity.

Systemic Soil Application

Dinotefuran (apply in the early spring or early fall)

Note: Soil-applied products containing imidacloprid do not effectively control armored scales, such as tea scale,  soft scales, such as cottony camellia scale.

Refer to Table 1 for examples of products for property owners. Apply all pesticides according to label directions.

Camellia Physiological & Environmental Problems

Camellia Problems: Bud Drop on Camellia

Camellia flower buds may drop from the plant before opening, or the tips of the young buds may turn brown.

Cause

• Large fluctuations in temperature
• Irregular moisture (too wet or too dry)
• Freezing temperatures
• Hot weather in fall or spring
• Poor drainage
• Nutrient deficiency
• Camellia bud mites
• Variety sensitivity
• Improper planting location

Symptoms

• Flower buds drop before opening
• Bud tips turn brown
• Buds develop slowly
• Buds open late or fail to open

Prevention & Treatment

Cultural Controls

• Plant in areas with consistent soil moisture
• Avoid sites that are excessively wet or dry
• Avoid planting late-blooming varieties in frost-prone locations
• Choose cooler, shadier planting sites when appropriate
• Improve drainage if needed
• Correct nutrient deficiencies based on soil testing (Soil Testing (HGIC 1652))
• Transplant if site conditions are unsuitable

Camellia Problems: Sunscald on Camellia

Sunscald is a physiological injury that occurs when camellia foliage is exposed to excessive direct sunlight.

Cause

Sunscald typically occurs when:

• Camellias are planted in full sun
• Plants are placed against south- or west-facing walls
• Shaded plants are transplanted into sunny locations

Symptoms

• Scorched or bronzed leaf areas
• Damage on the sun-exposed side of the plant
• Secondary leaf-spot fungi on damaged leaves

Prevention & Treatment

Cultural Controls

• Plant camellias in partial shade
• Provide shade in excessively sunny locations
• Avoid sudden transition from shade to full sun

Leaves that have turned brown will not recover.

Camellia Problems: Oedema on Camellia

Oedema (sometimes spelled edema) is a physiological disorder of camellia leaves caused by excessive water uptake by the roots and a reduced ability of the foliage to transpire (or give off) this buildup of water within the leaves.

Cause

Oedema occurs when:

• Soil moisture is excessive
• Cool temperatures reduce transpiration
• Extended cloudy weather increases relative humidity
• Roots absorb more water than leaves can release

Symptoms

• Small, water-soaked, greenish-white raised areas on lower leaf surfaces
• Blisters rupture
• Rust-brown or yellow-brown corky patches
• Wart-like dead tissue
• Most common in late winter or early spring

Prevention & Treatment

Cultural Controls

• Improve air circulation
• Increase sunlight by pruning adjacent plants and overhanging tree limbs
• Avoid overwatering
• Monitor soil moisture
• Plant in well-drained soil
• Maintain proper soil fertility through soil testing (HGIC 1652, Soil Testing)

Oedema does not significantly harm plant health, and no spray controls are effective.

Camellia Problems: Magnesium Deficiency in Camellia

Magnesium deficiency is a nutritional disorder affecting older camellia foliage.

Cause

• Soil contains excessive calcium
• Soil contains excessive potassium
• Nutrient balance is disrupted

Symptoms

• Interveinal chlorosis on older leaves
• Yellowing between leaf veins
• Yellowing along leaf margins (edges)
• Premature leaf drop (in severe cases)

Do not confuse deficiency-related leaf drop with normal evergreen seasonal leaf drop in late spring as new foliage emerges.

Prevention & Treatment

• Fertilize based on soil test recommendations (HGIC 1652, Soil Testing)
• Apply Epsom salt solution (1 tablespoon per gallon of water) if deficiency is confirmed

Note: Control of diseases and insects on large shrubs and trees is usually not feasible, since adequate coverage of the foliage with a pesticide cannot be achieved.

Fungicides and Insecticides to Control Camellia Diseases and Insect Pests (Table 1)

The following active ingredients are labeled for the management of camellia diseases and insect pests. Products are organized alphabetically by active ingredient.

Insecticides

Active Ingredient	Examples of Products
Acephate	BioAdvanced Science-Based Solutions 2-in-1 Systemic Rose & Flower Care Granules with 6-9-6 Fertilizer Bonide Systemic Insect Control II
Bifenthrin	Hi-Yield Bug Blaster Bifenthrin 2.4 Ready to Spray Hi-Yield Bug Blaster II Bifenthrin 2.4 Ready to Spray Monterey Mite & Insect Control Monterey Mosquito Control Martin’s FLEE Ready to Use Yard Spray Ortho Outdoor Insect Killer Concentrate Ortho Bug B Gon Insect Killer for Lawns & Gardens1 Ortho BugClear Insect Killer for Lawns & Landscapes Bifen I/T Talstar P Professional Insecticide Up-Star Gold Insecticide Hi-Yield Vegetable & Ornamental Insect Control Granules Bonide Eight Insect Control Flower & Vegetable Above & Below Soil Insect Granules
Cyfluthrin	BioAdvanced Science-Based Solutions 24 Hour Lawn Insect Killer Ready-to-Spray BioAdvanced Science-Based Solutions Complete Brand Insect Killer for Soil & Turf Ready-to-Spray I BioAdvanced Science-Based Solutions Insect Killer for Lawns Ready-to-Spray BioAdvanced Science-Based Solutions Rose & Flower Insect Killer Ready-to-Use
Dinotefuran	Gordon’s Zylam Liquid Systemic Insecticide Valent Safari 20 SG Insecticide
Horticultural oil	Bonide All Seasons Horticulture Spray Oil Ready-to-Use Bonide All Seasons Horticulture & Dormant Spray Oil Ready-to-Spray Ferti-lome Horticultural Oil Spray Monterey Horticultural Oil Concentrate Monterey Horticultural Oil RTU Safer Brand Horticultural & Dormant Spray Oil Concentrate Southern Ag Parafine Horticultural Oil Summit Year-Round Spray Oil
Cyhalothrin	Bonide Eight Insect Control Garden & Home II Ready to Use Cutter Backyard Bug Control Spray Concentrate Cyzmic CS Controlled Release Insecticide Martin’s Cyonara Lawn & Garden Insect Control Martin’s Cyonara Lawn & Garden Insect Control Ready-to-Spray Spectracide Triazicide Insect Killer for Lawns & Landscapes
Malathion	Bonide Malathion 50% Insect Control Gordon’s Malathion 50% Spray Hi-Yield 55% Malathion Insect Spray Martin’s Malathion 57% Ortho Max Malathion Insect Spray Concentrate Southern Ag Malathion 50% EC Spectracide Malathion Insect Spray Concentrate Tiger Brand 50% Malathion
Permethrin	Bonide Eight Insect Control Vegetable, Fruit, & Flower Concentrate Bonide Eight Yard & Garden Ready to Spray Hi-Yield 38 Plus Turf, Termite & Ornamental Insect Control Hi-Yield Lawn Garden Pet & Farm Insect Control Southern Ag Permetrol Lawn & Garden Insecticide Tiger Brand Super 10 Brand
RTS = Ready to Spray (hose-end applicator) RTU = Ready to Use (pre-mixed spray bottle)

Fungicides

Active Ingredient	Examples of Products
Captan	Arysta LifeScience Captan 50 Wettable Powder Fungicide Drexel Captan 50W Fungicide Southern Ag Captan Fungicide
Copper Fungicide	Bonide Captain Jack’s Liquid Copper Fungicide Bonide Copper Fungicide Spray or Dust Ready to Use Camelot O Fungicide/Bactericide Monterey Copper Fungicide Garden Spray Liqui-Cop Natural Guard by ferti-lome Copper Soap Fungicide Concentrate Natural Guard by ferti-lome Copper Soap Fungicide Ready to Use Southern Ag Liquid Copper Fungicide
Horticultural oil	Bonide All Seasons Horticulture Spray Oil Ready-to-Use Bonide All Seasons Horticulture & Dormant Spray Oil Ready-to-Spray Ferti-lome Horticultural Oil Spray Monterey Horticultural Oil Concentrate Monterey Horticultural Oil RTU Safer Brand Horticultural & Dormant Spray Oil Concentrate Southern Ag Parafine Horticultural Oil Summit Year-Round Spray Oil
Mancozeb	Bonide Mancozeb Flowable with Zinc Concentrate Southern Ag Dithane M-45
Thiophanate Methyl	Southern Ag Thiomyl Systemic Fungicide
RTS = Ready to Spray (hose-end applicator) RTU = Ready to Use (pre-mixed spray bottle)

Pesticide Safety and Pollinator Protection

• Do not apply horticultural oils above 90°F or to drought-stressed plants
• Spray late in the day
• Avoid unnecessary pesticide use
• Apply sprays in the evening to reduce impact on pollinators
• Prioritize cultural controls before chemical options
• Use less toxic alternatives when chemicals are necessary
• Less toxic alternatives include: insecticidal soap, horticultural oil, neem oil extract, Spinosad, Bacillus thuringiensis (B.t.), botanical oils
• If soil-applied systemic insecticides are used, apply immediately after flowering
• Always read and follow all label instructions and precautions

Pesticides are updated annually. The last updates were made on 2/26 by N. Jordan Franklin.

Originally published 05/99