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
–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
Root Rot Management
•Remove
diseased
plants and
roots
•Fumigate soil
before
replanting
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!
Root Knot Nematodes
•Endoparasitic
nematode
•Feeds on root tissues
•Dieback, decline,
chlorosis
•Identify under
microscope
Roots infected with
Meloidogyne are swollen.
Nematode Management
egg mass
•Fumigate
Meloidogyne sp.
•Solarize soil
•Buy plants grafted with resistant varieties
•Provide adequate water and fertilizer
•Remove and replace plants and soil
Magnesium Deficiency
• 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
Gardenia augusta
•
Acid loving plant
•
Fragrant flowers
Gardenia- Key Pests
Diseases
•Stem
Canker
Other
•Nematodes
•Manganese
deficiency
•Environmental
stress
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 gardeniae
Notice 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
Meloidogyne sp
•Solarize soil
•Buy plants grafted with resistant varieties
•Provide adequate water and fertilizer
•Remove and replace plants and soil
Manganese Deficiency
• Interveinal chlorosis
on new growth
• Reduced leaf size
• Necrotic distortion
of new growth
• Common in alkaline
soils high in
phosphorous
Management
Use a complete fertilizer with micronutrients
Environmental Stress
• 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
Chlorosis
Bud drop
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
•Galls can appear
on any plant part
and may be due
to bacteria, fungi,
nematodes, or
insects.
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.
Petal Blight
• 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
Cibornia camelliae
(formerly Sclerotinia)
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.
Fungal Leaf Spot
• Circular or irregular lesions
• Margins raised
• Brown - gray
• Fungus favors high
humidity and partial shade
Management
• Limit overhead irrigation
• Avoid crowding
• Copper fungicides
Cerscospora caloloma
Algal Leaf Spot
•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
Cephaleuros virescens
Twig Dieback
•Fungus
•Summer-winter:
Glomerella cingulara
• cankers
•Spring:
• Young shoots
wilt and die
• Brown leaves
remain on the
dead shoots
Twig dieback and a healthy camellia.
Twig Dieback
• 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
Management
• Prune infected areas,
including cankers
• Fungicides
Environmental Stress
•High heat and light
•Temperature
fluctuation
•Drought
•Mechanical damage
Bud Drop
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
Erwinia amylovora
• Spread by bees
and splashing
water
Fireblight
• Bacteria enter through
flowers and infection
spreads into the stem
Management
• Limit overhead
irrigation
• Remove infected
branches
• Use resistant varieties
Acknowledgements
Authors:
Reviewers:
Funding:
Photos:
Rebecca McNair
Dr. Russ Mizell, Dr. Norman Leppla, Dr. Doug
Caldwell, Celeste White, and Christine KellyBegazo
Florida Yards and Neighborhoods
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. Lance Osborne
Dr. Norman Leppla
Bill Graves
Holly Glenn
Dr. Eileen Buss
Dr.
Dr.
Dr.
Dr.
Dr.
Catherine Mannion
Avas Hamon
George Agrios
Doug Caldwell
Tim Schubert