Transcript Tree Diseases - Advanced Master Gardener

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
Non-Living Factors
Often cause disease-like symptoms
AND contribute to disease susceptibility
Janet will cover this aspect
 Nutrient Deficiency
 Water Stress
 Temperature Stress
 Other
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?