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Key Plants and Key Pests in North Florida Landscapes Podocarpus, Gardenia, Camellia, and Pyracantha. Rebecca McNair University of Florida Extension. IPM Integrated Pest Management. Natural processes of control are emphasized Host plant resistance Pest exclusion - PowerPoint PPT Presentation
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Key Plants and Key Pests in North Florida
Landscapes Podocarpus, Gardenia,
Camellia, and Pyracantha
Rebecca McNair
University of Florida Extension
IPMIntegrated Pest
Management•Natural processes of control are emphasized
–Host plant resistance–Pest exclusion–Prevention and through cultural practices–Physical Control–Biological control through natural enemies–Chemical control as a last resort
•Tolerance •Monitoring
Podocarpus
Nageia nagi
Podocarpus- Key Pests
Diseases
•Mushroom root rot
Other
• Nematodes
• Magnesium deficiency
Mushroom Root Rot •Slow decline,
thinning of canopy
•Gray-green color
•White mycelia under bark at soil line
Armillaria tabescens
•Remove diseased plants and roots
•Fumigate soil before replanting
Root Rot Management
Armillaria tabescens fruiting body appears in fall.
Root nodules •Beneficial nitrogen-fixing blue green algae
•Often mistaken for root knot nematodes
•Active nodules have a pink milky fluid in their centers
Hemoglobin within the nodule fixes atmospheric nitrogen. When exposed to
oxygen, the fluid inside changes from blue to pink!
•Endoparasitic nematode
•Feeds on root tissues
•Dieback, decline, chlorosis
•Identify under microscope
Roots infected with Meloidogyne are
swollen.
Root Knot Nematodes
Nematode Management
Meloidogyne sp.•Fumigate•Solarize soil•Buy plants grafted with resistant varieties•Provide adequate water and fertilizer•Remove and replace plants and soil
egg mass
•Yellow inverted “V”
•Occurs on mature leaves
•Low soil pH
•Lack of soil Mg
Management
•Increase pH with dolomite
•Apply Epsom salts or Mg fertilizers
Magnesium Deficiency
Gardenia augusta
• Acid loving plant
• Fragrant flowers
Gardenia- Key Pests
Other
•Nematodes
•Manganese deficiency
•Environmental stress
Diseases
•Stem Canker
Stem Canker
•Sudden wilting
•Chlorosis
•Leaf spots
•Yellow halo around lesions
•Stem cankers
•Galls, usually at the soil line
•Girdling may occur
Stem Canker
•Fungus pathogen enters injured tissue
•Spores spread by splashing water
Management
•Minimize plant injury
•Avoid overhead irrigation Phomopsis
gardeniaeNotice the yellow halo around the leaf spots on this gardenia.
Nematodes
•Roundworms
•Root Knot nematodes live inside plant roots
•All live in liquids, i.e. water in soil
•Feed on plant sap
•Damage roots
•Inhibit growth
Root-Knot Nematodes•Decline and thinning of canopy
•Roots brown, stunted and galled
Decline due to root knot nematodes compared to a
healthy gardenia.
Nematode Management
•Fumigate•Solarize soil•Buy plants grafted with resistant varieties•Provide adequate water and fertilizer•Remove and replace plants and soil
Meloidogyne sp
Manganese Deficiency•Interveinal chlorosis on new growth
•Reduced leaf size
•Necrotic distortion of new growth
•Common in alkaline soils high in phosphorousManagement
Use a complete fertilizer with micronutrients
Environmental Stress
Bud drop
Chlorosis
•Excessive water or fertilizer•Cold or temperature fluctuation
•Nutrient Deficiency•Drought
•High pH
•Mechanical damage
Management•Correct cultural problems•Provide cold protection•Prune and re-grow
Camellia japonica
•Acid loving
•Prefers partial shade
•Fragrant flowers from late winter to early spring
Camellia- Key Pests
Diseases
•Crown Gall
•Petal blight
•Leaf spot
•Twig dieback
Other
•Environmental stress
Gall
Agrobacterium tumefaciens is a common soil bacterium that causes crown gall
disease by transferring some of its DNA to the plant host. This has enabled
scientists to genetically manipulate plants, a technique called transformation.
•Galls can appear on any plant part and may be due to bacteria, fungi, nematodes, or insects.
Petal Blight
Cibornia camelliae (formerly Sclerotinia)
•Irregular, brown spots
•Dark veins
•Blighted flowers drop
•Prefer warm, moist conditions
•Ascospores are spread by water
•Fungus overwinters as sclerotia, a hard black structure that remains viable for 5 years Sclerotia
Petal Blight Control
•Suppress sclerotia development
•Remove all infected flowers, leaves, and litter
•Promptly burn or bury diseased materials (at least 1 ft deep)
•Limit overhead irrigation Cibornia
camelliae fruiting body.
Cerscospora caloloma
•Circular or irregular lesions
•Margins raised
•Brown - gray
•Fungus favors high humidity and partial shade
Management
•Limit overhead irrigation
•Avoid crowding
•Copper fungicides
Fungal Leaf Spot
Algal Leaf Spot
Cephaleuros virescens
•Wide host range
•Smooth leathery leaves are more prone to infection
•One of the few green algae parasitic on higher plants
Management
•Limit overhead irrigation
Twig Dieback
Twig dieback and a healthy camellia.
•Fungus
•Summer-winter:
• cankers
•Spring:
•Young shoots wilt and die
•Brown leaves remain on the dead shoots
Glomerella cingulara
Twig Dieback
Management
•Prune infected areas, including cankers
•Fungicides
•Leaf scars are most common point of entry
•Often confused with root rots
•Plants can be infected by both
•Root rot increases the severity of twig dieback
Environmental Stress
Bud Drop
•High heat and light
•Temperature fluctuation
•Drought
•Mechanical damage
Management
•Maintain adequate water
Pyracantha coccinea
•Firethorn
•Prefers full sun
•Will grow in partial to fairly heavy shade
•Fast growing
Pyracantha- Key Pests
Diseases
•Fireblight
Fireblight
•Bacterium
•New shoots wilt suddenly and die
•Dead leaves remain on the shoots
•Spread by bees and splashing water
Erwinia amylovora
Fireblight•Bacteria enter through flowers and infection spreads into the stem
Management
•Limit overhead irrigation
•Remove infected branches
•Use resistant varieties
Authors: Rebecca McNairReviewers: Dr. Russ Mizell, Dr. Norman Leppla, Dr. Doug Caldwell, Celeste White, and Christine Kelly- BegazoFunding: Florida Yards and NeighborhoodsPhotos: Thanks to the Florida Dept. of Agriculture and Consumer Services, Division of Plant Industry, and University of Florida Extension faculty for providing photographs, including:
Dr. James Castner Dr. Catherine MannionDr. Lance Osborne Dr. Avas HamonDr. Norman Leppla Dr. George AgriosBill Graves Dr. Doug CaldwellHolly Glenn Dr. Tim SchubertDr. Eileen Buss
Acknowledgements