Common Conifer Diseases of Forests · Jack pine and white spruce ... *Sporax by Wilbur-Ellis is a...
Transcript of Common Conifer Diseases of Forests · Jack pine and white spruce ... *Sporax by Wilbur-Ellis is a...
Nancy R. PatakyDirector, Plant Clinic University of Illinois
Common Conifer Diseases of Forests
Illinois (University of Illinois)Plant Clinic1401 W. St.Mary’s RdUrbana, IL 61802http://plantclinic.cropsci.illinois.edu/
Iowa (Iowa State University)Plant and Insect Diagnostic Clinic327 Bessey HallAmes, IA 50011http://plpfserve.plp.iastate.edu/pdc/welcome
Wisconsin (University of Wisconsin)Plant Disease Diagnostics Clinic1630 Linden DriveMadison, WI 53706-1598http://www.plantpath.wisc.edu/pddc/
Tri-State University Plant Clinic Contacts
Plant Clinic 1401 W. St. Mary’s Rd. Urbana, IL 61802
217-333-0519
May thru mid-September
Today Our Focus is on the Forest
Forest
NurseryLandscape
Plant Disease
Pyramid
Conditions necessary for plant disease to occur
Host
Pathogen Favorable Environment
Time
Pathogen-Agent causing theinfectious disease
A.Fungi
B.Bacteria
C.Virus
D.Nematodes
Most conifer diseases are caused by a fungal pathogen.
One disease discussed today is caused by a nematode.
Conifer Diseases Prevalent in Forests
1.Foliar Disease
2.Foliar & Stem Disease
3.Stem Disease
4.Wilts
5.Root / Butt Rots
Needle cast – New needles green, one year old needles brown, two year old needles cast (dropped)
Lophodermium
Swiss needle cast
Rhizosphaera needle castCyclaneusma needle cast
Needle blight – affects needles of any age with affected needles usually remaining attached
Brown Spot Needle Blight Dothistroma Needle Blight
Management of Needle DiseasesForest Trees: Most have no impact
But…be certain of your diagnosis
Ornamental:
Improve air flow
Resistant varieties, where possible • Ex. Norway Spruce resistant to Rhizosphaera
Protective fungicides• Rhabdocline, Rhizosphaera, Swiss Needle Cast in Spring
• Cyclaneusa & Lophodermium in Summer
Conifer Diseases Prevalent in Forests
1.Foliar Disease
2.Foliar & Stem Disease
3.Stem Disease
4.Wilts
5.Root / Butt Rots
Diplodia Blight of Pine•Symptoms appear on both foliage and stems•Cankers may be present
Diplodia Blight of Pine – Fruiting bodies and spores
Fruiting bodies on needles
Spores
Fruiting bodies on cones
Diplodia Canker Phase
Diplodia/Sphaeropsis tip blight and canker
• Hosts– Austrian, Scotch, &
Ponderosa pine (& other stressedconifers)
• Symptoms & signs– Shoot tip die-back– Branch cankers on
stressed trees– Fruiting bodies at
base of needle clusters and on cone scales
Diplodia ManagementForest Trees: Impact mostly to seedlings
Ornamentals: Serious
Remove infected wood or cones when dormant
Do not plant susceptible pines near mature, infected trees
Fungicides ? – three sprays: bud break, half candle, full candle
Efficacy of Sprays for Diplodia?•Latent infection of healthy Austrian & Scotch pines is common. (Kentucky study, 2001)
•If fungicides are used, pick systemic product
•Stressed trees more susceptible (multiple studies) – especially drought
Conifer Diseases Prevalent in Forests
1.Foliar Disease
2.Foliar & Stem Disease
3.Stem Disease
4.Wilts
5.Root / Butt Rots
Stem DiseasesCankers are the primary symptom. Dieback follows. Often stress related. Cytospora
on spruce
Cytosporaof Spruce
Typically affects lower part of tree first and moves upward each year
CytosporaCanker of Spruce
Cytospora (Leucostoma) Canker of Spruce
Gummy exudate and canker below. Probably won’t see fruiting bodies.
Management: Cytospora Canker of SpruceForest Trees: Not an issue. Urban
stress absent
Ornamentals:•Find source of stress•Correct stress•Remove dead wood•Improve vitality
Scleroderris Canker (Gremmeniella abietina)
•Causes shoot and possibly tree death
•Scotch, Jack, Red pines –Northern Wisc
•Stress is definitely a factor
•Infection 1o May-July via buds or needles, but symptoms next spring
Scleroderris Canker of Conifers1. Lake Strain
Young trees 6’ or lessBud dieback, orange base to needlesCankers on young trees – lowest branches under snowYellow-green stain in cambium
2. European StrainAll pines
Much more serious –may kill treesNot in Midwest
Orange base to needles in Spring
Threat to young trees 6’ or less
Scleroderris Canker Management
Ornamentals: Not an issue
Forest Trees:
Do not replant in an affected area
Use only disease-free stock in the Spring
Chemicals available in nurseries
Quarantines on Christmas trees grown in areas with European strain
Some resistant varieties
White pine blister rustHosts – Needs both
White Pine Ribes (currant and gooseberry)
Currant
White pine
Favored by cool, moist conditions and in low lying areas
White pine blister rust
Spores released by Ribes specis in midsummer to early fall cause yellow or reddish spots on pine needles.
Infected pine needles may turn yellow and drop.
Fungus moves into branch and swollen and blistered pine twigs & branches develop 2-3 years later.
Girdled branches are blister rust flags…..Probably what we see first
White Pine Blister Rust Cankers Later Exude Resin
White pine blister rust Management•Prune infected branches well before they reach the trunk
May work on ornamental trees
Not practical for forest
•Remove alternate hosts within 1,000 ft
•Seek rust-resistant planting stock
**Interesting Note:
The first quarantine laws were enacted in 1912, because of the need to control movement of this fungus. The fungus is from Asia but white pine is native. Imported on European white pine breeding stock
Pine gall rusts• Hosts
– Austrian and Scotch pine• Symptoms & signs
– Swellings and galls on main stems or branches
– 2 yr-old galls release yellow spores in spring
• W. gall rust pathogen re-infects pine only
• E. gall rust pathogen infects oak (red/black) then back to pine (all within 3-4 wks)
Pine
Mature & active gall
Immature gall
Pine gall rustsGalls often not noticed
during first year after infection
Before spring, remove infected pine branches or whole trees
Check nearby wild areasApply Bayleton or
mancozeb every 7-14 days during pine shoot elongation.
Gouty Oak GallCaused by an insect
(wasp)
Management of Rust Diseases•White pine blister rust branches pruned and removed. Remove Ribes alternate hosts. No fungicides
•Pine gall rusts are pruned in early spring. Fungicides may help ornamental or nursery stock.
•Problem in nurseries
•Problem in Jack pine plantations
Conifer Diseases Prevalent in Forests
1.Foliar Disease
2.Foliar & Stem Disease
3.Stem Disease
4.Wilts
5.Root / Butt Rots
Vascular Diseases
Pine Wilt is the only vascular disease of conifers in the Midwest.
Pathogen invades the water conducting system of the tree
Pine
Pine Wilt caused by pinewood nematode
Kills trees in a season
All pines are host except white pine (usually)
Vector – Pine Sawyer Beetle
Wood extract for PWN assay
Pinewood nematodes viewed through a dissecting microscope
Pine Wilt Management• Correctly Identify• Remove tree before mid-March• Chip, burn, or bury tree• No chemicals effective
Conifer Diseases Prevalent in Forests
1.Foliar Disease
2.Foliar & Stem Disease
3.Stem Disease
4.Wilts
5.Root / Butt Rots
Root RotsSymptoms include off-color foliage, smaller than normal leaves, stem dieback, leaf scorch, branch death, wilt, decline, and possible plant death.
White Pine
Armillaria root rot• Hosts
– Hundreds of woody plants• Symptoms & signs
– Young trees suddenly turn yellow, then reddish-brown, then die. (usually following moisture stress)
– White mycelium under the bark at the base of the tree
– Spongy or stringy white wood rot
– Honey mushrooms
Look for white mycelial fans of growth between bark wood
Aka Shoestring Root Rot because of rhizomorphs
Armillaria Root Rot Fruiting Bodies
FBs Produced in late summer or fall
Armillaria root rot spreadAirborne spores (occasional)
Growth of fungus from tree to tree
Rhizomorphs
Root grafts
Armillaria ManagementAvoid using recently cleared land, especially deciduous forests.
Remove infested stumps and roots –may survive for decades in large stumps (for high value sites)
Reduce stress. Use local seed source.
No effective, practical control
Annosum Root Rot (Heterobasidion annosum) (Fomes annosus)
•Decay of roots and butt
•Often kills
•Over 200 hosts including red, white, Jack pine and white spruce
•Infects through freshly cut stumps and moves to healthy trees via roots
Image by Joseph O’Brien
Symptoms•Reduced growth, but often none aboveground until the tree dies
•Windthrown trees
•Stained and resin soaked wood in butt of tree and roots leak resin
•Wood soft and stringy
•Stringy yellow decay in roots
Image by William Jacobi
Annosum Root RotWhite mycelium under bark
Basidiocarps around base of stump
mid-summer popcorn appearance
fall bracket shaped
Image by Paul A. Mistretta
Annosum Root Rot Management•Treat cut stumps to prevent establishment
Big problem in plantations where thinned
Not so much of a forest problem
Sporax* or other registered product
•Avoid planting in site formerly used for agriculture
•Avoid areas with a pH>6
•Disease favored by well drained, sandy soils
*Sporax by Wilbur-Ellis is a borate based fungicide registered for use to control this fungus
Schweinitzii Root and Butt Rot (Phaeolus schweinitzii)•Common on conifers, espDouglas fir
•Enters wounds
•Primarily root rot
•Forms very ornamental conks on stumps and roots (dye source)
Start yellow-green
then yellow-brown
then dark brown
By Andrej Kunca
by Larry Grand
Image by James Byler
Schweinitzii causes a brown cubical rot of upper roots and lower bole
White Pine Decline
White Pine Decline
•Delayed bud break•Reduced shoot elongation•Wilting and browning•Dead needles hold on•Exact Cause Unknown
White Pine Roots
White Pine Decline Healthy
Procerum root diseaseHosts
E. white, Austrian, & Scotch pine
Vector implicatedWeevils & bark beetles
Symptoms & signsDelayed bud-break &
reduced shoot lengthWilting and uniform
browning of needlesResin at base of tree &
evidence of insect attack
Procerum root disease
• Conditions– Various stress factors– Common on wet or poorly
drained sites• Management
– Avoid using stress-prone planting sites
– Remove infected stumps.
Leptographium procerum
Stained wood near the base of the tree and excessive sap exudate at the soil line are symptoms of this disease.
Causal fungus
Management of Root Rot Diseases
•Promote tree health to ward off problems
•Plant in well drained sites
•Plant in site appropriate to species needs
•Remove stumps and roots of dead trees
•Fungicides may help in nursery setting
•Does it help to remove conks? NO!
Helpful References are Listed in Handout
http://www.aces.uiuc.edu/~vista/rpd.html
How to Submit a Sample to a Plant Clinic
•Address to local plant clinic
•Provide Information
•Sample live, symptomatic areas
•Provide enough to work with and share
•Do not use plastic
•Use sturdy box
•Provide Pictures
What do I send to a lab?
What do I send to a lab from these spruces?
Illinois (University of Illinois)Plant Clinic1401 W. St.Mary’s RdUrbana, IL 61802http://plantclinic.cropsci.illinois.edu/
Iowa (Iowa State University)Plant and Insect Diagnostic Clinic327 Bessey HallAmes, IA 50011http://plpfserve.plp.iastate.edu/pdc/welcome
Wisconsin (University of Wisconsin)Plant Disease Diagnostics Clinic1630 Linden DriveMadison, WI 53706-1598http://www.plantpath.wisc.edu/pddc/
Tri-State University Plant Clinic Contacts
Nancy PatakyUniv of IllinoisPlant Clinic [email protected]