Tree Pests and Diseases - Advanced Master Gardener
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Transcript Tree Pests and Diseases - Advanced Master Gardener
Trees Pests and Diseases
Developed by:
Janet Anastasi, Master Gardener Volunteer
Frank Reilly, Advanced Master Gardener & Tree Steward
Leslie Paulson, Advanced Master Gardener & Tree Steward
With input from
Page Thacker, Unit Coordinator & Extension Agent
And the
Prince William County Tree Team
http://advancedmastergardener.org/public.htm
Trees Pests and Diseases
Environmental and other Non-Living
Factors
Developed by:
Janet Anastasi, Master Gardener Volunteer
in cooperation with:
Chuck Hoysa, Past Extension Agent and Soil & Water Conservation
District Educator
Joe Murray, Consulting Arborist and Assistant Professor of Biology
Arboriculture Program Director, Blue Ridge Community College
Mila Pearce, IPM Diagnostic Lab, &
Gary Peiffer, County Extension Agent,
The University of Georgia
Cooperative Extension
Environmental
Factors
Why Plant a Tree?
Provide shade
Provide aesthetics in the
landscape
Improve air quality
Reduce storm-water runoff
and improve water quality
Create wildlife habitat
Reduce noise levels
Provide screening and
privacy
Tree Roots – where they are?
TYPES OF CONSTRUCTION
DAMAGE
Environmental Changes
Soil
compaction
Excessive thinning
Moisture stress
Soil fill
Soil cuts
Soil Compaction
Causes:
Running of heavy
equipment over root
zones
Piling of debris on top
of tree roots
Parking under a tree
Soil Contamination
Prevent soil contamination that
can damage or kill trees!
Watch out for fuel leaks.
Do not allow on-site paint
dumping.
Plan for cement or mortar
wash out areas.
Is this a good home
building site?
Site Factors
Environmental
Conditions
Light
patterns
Temperature
extremes
Precipitation
Wind
patterns
Air quality
Site Factors
Soil characteristics
Texture
Compaction
Moisture &
drainage
Fertility and pH
Temperature
Contamination
Salt
Non-Living Factors
Nutrient Deficiency
Water Stress
Temperature Stress
Other
What is the Right Tree?
Growth factors
Soil requirements
Other
Environmental
requirements
Maintenance
requirements
Right Tree
Other environmental
factors
Hardiness zone
Wind and storm
damage
Light requirements
Pollution tolerance
Insect and disease
tolerance
Tree Care after Construction
Aerate or use other soil alteration
methods to re-introduce oxygen and
reduce compaction.
Water deeply – to encourage new root
development and reduce tree stress.
Inspect frequently – look for visible signs
of insect or disease attack.
Mulch – them well but correctly!
Fertilize – in a year or two after they have
recovered from construction stress.
Non-living and Cultural
Factors
Can be tricky to diagnose
Good to know what is ‘normal’
Knowledge of past weather conditions
Knowledge of past cultural practices
Often referred to as disorders
Chlorosis
Yellow leaves with
green veins
Indicates nutrient
deficiency
Can be a fertilizer or
pH problem
Can affect all trees pin oak - dogwood
Leaf Scorch
Lack of water
Common on newly
planted trees
Can occur on
established trees
during drought
Common on trees
with restricted roots
Winter Damage
Timing is key
Late winter, early
spring, before new
growth emerges
Most common on
broad leaf
evergreens
Can show up as leaf
scorch, dead
branches
Herbicide Damage
Knowledge of use
Distorted growth,
especially at
growing points
Most susceptible in
spring as new
growth emerges
Damage can be
widespread
Needle Shedding
Common on pines,
especially white pine
Also occurs on other
evergreens
Knowledge of plant
is helpful
Look at other plants
in neighborhood
Trees Diseases
Developed by:
Frank Reilly, Advanced Master Gardener Volunteer
in cooperation with:
Chuck Hoysa, Past Extension Agent and Soil & Water Conservation
District Educator
Joe Murray, Consulting Arborist and Assistant Professor of Biology
Arboriculture Program Director, Blue Ridge Community College
Mila Pearce, IPM Diagnostic Lab, &
Gary Peiffer, County Extension Agent,
The University of Georgia
Cooperative Extension
Conditions Necessary for
Plant Disease
Pathogen
Susceptible
Host
Telephone call to
Cooperative
Extension!
Favorable Environment
Take Home Message
Right Plant Right Place
If you paid attention to the rest of these
classes you can ignore most of the rest
of this talk.
Diagnosis
Accurately ID the plant – THE MOST
important step!
Look for patterns of abnormalities
Diagnosis
Examine the site
Diagnosis
Look at the foliage
Diagnosis
Look at the trunk
and branches
Diagnosis
Look at the roots and
root collar
Diagnosis
Symptoms vs. signs
Symptoms - expressions of disease
initiation that differentiate them from
healthy plants nearby
Signs - vegetative or fruiting
(reproductive) structures of the
organism that is causing the disease
Disease Symptoms
Spots - circular or irregular lesions on
leaves, flowers, and stems
Blights - sudden death of leaves,
flowers, and twigs
Galls - abnormal growths or swelling
Cankers - dead places on bark and
stems
Rots - general decomposition of tissue
Insect Damage
Leslie will talk about this
Some insect
damage can look
like disease
Sooty mold - grows
on honeydew
Scales, mealybugs,
mites, adelgids,
borers can all cause
damage that looks
like disease
Top 10 Diseases
You are “likely” to encounter.
Powdery mildews:
*Found world wide
*Over 7000 species
*Gymnosperms are not infected
*Obligate parasites
Powdery mildews:
Found world wide
Over 7000 species
Gymnosperms are not infected
Favorable conditions:
Obligate parasites
*Dry, warm days
*Cool nights
*Water inhibits germination,
but humidity does not
Anthracnose: Fungal disease of a wide
variety of broad-leaved trees causing symptoms
that vary from small necrotic leaf spots to
blight of leaves.
Primary causal agents:
Colletotrichum
Kabetiella
Phyllosticta
Gloeosporium
Discula
many more…..
Discula on Dogwood
Dieback caused by Discula
Discula petal blight
Control: Anthracnose on some species is not warranted because of location or
the disease presents no long term damage. Maintain tree vigor with proper
watering, fertilization, good drainage, etc.Valuable shade trees may be pruned to
reduce severity and increase life span of the tree.
Septoria leaf spot
- circular spots formed when a fungus
attacks at bud break. Control should
therefore be attempted at that time.
Septoria species attack a wide variety
of trees.
Fire blight - common to several Prunus species greatest
damage on apples, crabapples and pears
Symptomology:
Sudden blighting, death of blooms
Bacterial ooze may be visible
Blighted leaves stay attached
Forms shepard’s crook
Control:
Plant tolerant varieties
Prune infected branches
Disinfect pruning tools
Maintain plant vigor
Control insect vectors
Sprayed on antibiotics are
also recommended but they
are very costly and the
coverage and timing are the
keys to any success.
Cankers and Galls on trunks/branches - Seiridium Canker
Distinct, sunken lesions which lead to
dieback and death
Spores are dispersed throughout
the summer, but infection periods
are unknown
Dieback is from the inside out
Hosts include :
Oriental arborvitae
Baldcypress
Arizona cypress
Italian cypress
Leyland cypress
Junipers
Flattened cankers are associated with bleeding and resin.
Control:
Remove cankers in winter
Do not prune in May or June
Increase plant health
No chemicals available
Phomopsis Tip Blight –
Disease of conifers causing
needle cast, dieback, and
death of highly susceptible
trees.
Control:
Fungicides can be effective if
applied according to label directions.
Pruning branches will limit inoculum
build-up.
Black Knot
Common gall on cherries,
plums, and peaches.
Symptoms include dieback of branches, thin
crowns, and gnarly black galls on trunk
or branches.
Control: Prune branch galls six to eight inches
below infection. It is impractical to remove trunk
galls.
Wetwood and Slimeflux
Caused by bacteria.
Hosts:
Oaks
Popular
Elms
Other symptoms:
fermentation smell, swarming
insects
Wetwood or slime flux
•bacterial infection
•initiated through root and/or
trunk wounds.
•Oozing occurs when bacterial
pressure builds up
•Trunk and bark staining
usually results.
•weakens trees but does not
directly cause their death.
Control:
•Cosmetic only.
•Use 10-20% bleach solution
•clean the bark surface.
•Do not drill to insert drain
tubes
•That spreads infection.
Wood Decay Fungi
Ganoderma
Inonotus
Hypoxylon
Hispidus Canker
Irpex Canker
Hypoxylon Canker
Symptomolgy:
Slighty sunken irregular areas on bark
Canker becomes blistered with clusters of perithecia
immersed in stromata causing the tree bark to exfoliate.
Colors vary from black, gray to tan.
Hypoxylon canker is most prevalent in
situations of weakened or stressed
hardwoods.
Hosts:
Oak
Beech
Hickory
Maples
Tupelo
Control measures include pruning out
branch cankers, surgically removing small
trunk cankers, fertilizing and watering to
improve tree vigor. These controls can slow
disease spread but do not often totally
eliminate it!
Hispidus Canker
Entry point for this fungus is usually through
old branch stubs or wounds. Causes a soft,
white heart rot.
Hispidus Canker
Primarily found on oak species
Once trunk decay fungi are actively growing, there is no
control. Improve tree vigor to add to its lifespan!
Vascular Wilts
Diseases that interfere with the
uptake and flow of water
and nutrients.
Verticillium
Wilt
Sample Hosts:
Maple, Ash, Elms,
Magnolia, Redbud
Tulip Poplar
Symptoms include:
•curling,
•drying,
•interveinal chlorosis
or
•reddening,
•defoliation,
•wilting,
•dieback and death.
•Infection occurs on
stressed trees
•initiated through the
roots and wounds.
Dutch Elm Disease DED
Yellowing, flagging and
branch dieback
Staining under bark
Control:
Prune infected branches and monitor insect vectors (elm bark beetles).
Prevent root grafts through appropriate use of trenching methods.
Plant resistant varieties such as Chinese Elms and Zelkova Elms.
Annosum Root Rot
PrimaryHosts:
Cedar
Hemlock
Pines
Symptoms include general
tree decline and wind-throw.
What Next?
Most diseases we encounter are cosmetic
Sanitation - prune and rake
Remove problem trees
Plant appropriate or disease resistant
trees
Spraying is often not an option
Get a positive ID before any treatment
Start with a good sample
What makes a good sample?
Distinct symptoms
Fresh sample
Whole section of
branch or handful
leaves
Junction of live and
dead tissue
What plant is it!
What makes a bad sample?
All dead tissue
Single leaf
Been on dashboard
for a week
Damage occurred
months ago
Don’t know what
plant it is
Some Cool Ones to
Know
HOW AM I DOING ON TIME?
Oak Leaf Blister (caused by a fungus) is more common during cool,
wet springs. Leaves remain attached therefore little long term harm
to tree.
Witches’ Broom caused by powdery mildew on Witchhazel
but there are many causes such as diseases, insects,
frost, drought, etc.
Witches’ Broom caused by
mites and powdery
mildew on Hackberry tree.
Cedar Apple Rust
Galls are abnormal growth responses
caused by fungi, insects, and bacteria
Mature gall
Actively sporulating
galls
Alternate host leaf spot.
Most often seen on apples and
crabapples.
NEW DISEASES ON THE HORIZON
Sudden Oak Death, SOD, Phythophthora ramorum
Phythophthora ramorum
is a soil-borne fungus
accidentally shipped to
the Eastern USA in
nursery stock
shown to affect over 60
different ornamental
plants.
damaged and/or killed
many western tree
species but
we do not know what it
will do to eastern
varieties, especially our
oaks.
www.suddenoakdeath.org
Trees Pests
Developed by:
Leslie Paulson, Advanced Master Gardener Volunteer
in cooperation with:
Chuck Hoysa, Past Extension Agent and Soil & Water Conservation
District Educator
Joe Murray, Consulting Arborist and Assistant Professor of Biology
Arboriculture Program Director, Blue Ridge Community College
Mila Pearce, IPM Diagnostic Lab, &
Gary Peiffer & Jule-Lynne Macie, County Extension Agent,
The University of Georgia
Cooperative Extension
Insect Damage
Some insect
damage can look
like disease
Sooty mold - grows
on honeydew
Scales, mealybugs,
mites, adelgids,
borers can all cause
damage that looks
like disease
Insects are often blamed for
other’s damage:
Sapsuckers
Beaver
Herbicide damage
Deer
Lightning
Secondary pests
Too much or not
enough water
Squirrels, roof rats
String trimmer
Ants
Bees
Long horned beetles
Termites
When looking at damage:
Think mouthparts
– chewing
Wilting, yellowing – piercing sucking
Speckling – rasping sucking
Holes
The Real Boring Insects
Chewing mouthparts, so think
‘holes’
Bark Beetles
3 different beetles –
southern pine
beetle, Ips engraver,
Black turpentine
Needles turn yellow
from tips back
Larvae feed under
bark
Under the Bark
Beetles attack
stressed native pine
trees
Second generation
beetles attack
surrounding trees
Blue stain fungus
Galleries
Pitch Tubes
A sign of attack.
Beetles are
sometimes ‘stuck’ in
pitch
Control for Homeowners
Sanitation!
Homeowners do not
have equipment to
spray preventatively
Asian Ambrosia Beetles
Attack smooth bark
trees in early spring
when leaves expanding
Bore deep into
heartwood
Need moist wood
Toothpicks
No good chemical
control
Cut down
Various Wood Boring Beetles
Attack various
trees
Female lays eggs
on trunk and larva
bore under bark
E.g. Poplar Borer,
Emerald Ash Borer,
Lilac Borer, Bronze
Birch Borer
Emerald Ash Borer
aggressive wood borer
Responsible for fire wood
quarantine
“D”-shaped exit hole
Caterpillars
Chewing mouthparts so think
‘holes’
Bagworms
Deciduous and
evergreens
Insecticides only if
early in season
Fall – move to ends of
branch and pupate
Males fly to females
Lay eggs in bag
Prune and discard!
Tent Caterpillars
Spring pest
Tents in interior of tree
Prefer fruit trees
Pretty caterpillars
Capable of total
defoliation
Will not kill a tree
(usually)
Orange Striped Oakworm
Fall Pest of Oaks
Caterpillars feed
together
Begin life light green
and turn black with
stripes
Fall Webworms
fall webworm
appears I late
summer
nests grow until
entire branches are
covered
Seldom a danger to
the tree
Hickory Horned Devil
Regal Moth
Largest
Butterfly/moth
north of Mexico
Beetles
Both adult and larvae can cause
damage
Japanese Beetles
Turf pest
Adults difficult to
control
Attack the grubs
Sucking Insects
Needle-like mouth so think
yellowing, wilting and deformity
Bark Aphids
Wooly Alder Aphids
Piercing sucking
Suck plant sap
Honeydew
Sooty mold
30 generations a
year
Live birth
Wings at times
Aphids in general
Clients will often say
their problem is ants
on their plants
Aphids like tender
Nitrogen rich plant
tips
Can cause mildew
due to sweet
honeydew
Natural controls (e.g.
lady beetles)
Scales – Soft, Armored, Pit,
Oystershell, etc.
Piercing sucking
Crawlers – only
control stage
Waxy covering
Systemic
insecticides
Sooty mold
Other Insects
Miscellaneous damage, but is it
really necessary to control?
Galls
Leaf Miners
Death to
plant
uncommon
Discolors or
browns
leaves
Hard to
control –
remove
fallen leaves
Time
applications
exactly
Cicadas
Annual
Periodic
No long damage
except to young
saplings
Flagging
Different species (at
least 3)
Different broods
Lacebugs
Oak
Sycamore
Hawthorn
Azalea,
rhododendron
The End
Any Questions?
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