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Bark Beetle Management in Pines
Bill Schaupp, Entomologist, USDA Forest Service,
Forest Health Protection, Southwest Oregon
Jackson-Josephine Small Woodlands Association,
November 15, 2012
•Supervised by the Resources Staff Officer, Rogue River-
Siskiyou NF with offices and laboratory space
at the J. Herbert Stone Nursery
•Serving southwest Oregon from Cottage Grove to the
California border and the Pacific Coast to the Crest of the
Cascades
•Federal Clients include: Rogue River-Siskiyou and Umpqua
NFs, Coos Bay, Medford, and Roseburg BLM Districts, Oregon
Caves National Monument, Siletz BIA and Tribes served
•Work closely with our partners at ODF and ODA and
collaborate with researchers at OSU, and PSW and PNW
USDA-FS Research Stations
USDA Forest Service, Forest Health Protection Southwest Oregon Forest Insect and Disease Service Center
USDA Forest Service, Forest Health Protection
Southwest Oregon Forest Insect and Disease Service Center
Staff:
Josh Bronson -- Pathologist
(541-858-6124) or [email protected]
Ellen Michaels Goheen – Pathologist and Leader
(541-858-6126) or [email protected]
Bill Schaupp -- Entomologist
(541-858-6125) or [email protected]
Bob Schroeter – Natural Resource Specialist and Aerial Observer
(541-858-6123) or [email protected]
Recent retirees: Don Goheen, Entomologist/Pathologist
Katy Mallams, Pathologist
Frank Betlejewski, USFS Port-Orford-cedar Program Manager
Presentation Outline
1. Know the pests --- biology and ecology
2. Signs and symptoms
3. Bark beetle management strategies
4. Why thinning works
5. Considerations and cautions
6. Individual tree protection
7. Synthesis
WOODBORING INSECTS
• Primary: Bark Beetles
– Western & Mtn. pine beetle
– Pine engraver (Ips spp.)
– Fir engraver
– Douglas-fir beetle
• Secondary: Woodborers
– Flatheaded & Roundheaded
Woodborers
– Wood wasps
– Ambrosia beetles
Bark Beetles… What are they ??
• Small insects (beetles),
typically the size of a
grain of rice
• Native to local forests
• Integral parts of forest
ecosystems
• Many bark beetles are
tree species specific
WHAT DO BARK BEETLES EAT?
C-shaped larvae
BARK BEETLE DEVELOPMENT
Egg Larva Pupa Adult
What are they doing?
• Bark beetles colonize and kill trees
• They breed, feed and develop beneath the bark
of host trees
• Numbers of bark beetle generations vary
• Beetles introduce wood staining fungi and
bacteria that help disrupt moisture conducting
tissues in host trees
• Beetle populations can expand over short
periods of time, taking advantage of large
areas of susceptible forest
BARK BEETLES • Most important group of forest insects
in western North America
• Despite variety, many common features
1. Opportunistic - infest trees weakened by
other agents and/or factors
2. Communicate chemically - pheromones
aggregate and repel, yield group tree kills
3. Inoculate host tree with fungi and bacteria,
some with essential role in beetle life
4. Most of life spent beneath the bark
BARK BEETLE IMPACTS
• Forest dynamics
• Fire/fuels management
• Timber
• Recreation
• Wildlife
• Hydrology
• Forest Planning – “How many trees will they
kill?”
Bark Beetle
Population
Stand
Conditions
Weather
Conditions
BARK BEETLE DYNAMICS
• Outbreaks are common and driven by many factors
• Stand conditions (density, structure, tree species)
• Moisture levels / climate (drought, temperatures)
• Tree damaging events (storms, fire, defoliation)
Warner Mtns, Southcentral OR
Blowdown, Coastal OR
Pines Stressed by
• Mechanical Injuries
•Lightning
•Fire
•Disease
•Drought
•Old Age
•Competition
BARK BEETLE MANAGEMENT
STRATEGIES
• Alter bark beetle habitat
- thinning, salvage, stress reduction, non-hosts
• Kill beetles
- sanitation, burning infested, trapping
• Protect trees
- chemical pesticides, pheromones
Primary Bark
Beetles of Pines
Western Pine Beetle
(Dendroctonus brevicomis)
Host: Ponderosa Pine
Mountain Pine Beetle
(Dendroctonus ponderosae)
Hosts: All Pines
Pine Engravers
(Ips paraconfusus and I. pini)
HOSTS: All Pines
Smaller diameter material
Tops of larger trees
Breed in newly-created pine
slash
WHERE BARK
BEETLES
ATTACK ……
Evidence of infestation
1
2
3
4
Evidence of infestation (continued)
5
6
7
The Host vs. The Beetles
Pitch Tubes
(not always present)
Boring Dust
Woodpecker
Activity
Bark Beetles
Mountain Pine Beetle
Dendroctonus ponderosae
Western Pine Beetle
Dendroctonus brevicomis
Pine Engravers
What Eats Bark Beetles?
Pine Mortality
In SW Oregon
Are bark beetles
active near you ?
http://www.fs.usda.gov/goto/r6/fhp/ads
Forest Health Monitoring
Aerial Survey Program - Annual tree mortality survey
• Flown annually since 1951
• Cover ALL forested lands in WA and OR
• Same way each year
– 2 observers
– Fixed wing
– 4-mile grid
• Ground-checking for Quality Assurance and Quality Control
• Southwest Oregon data digitized back to 1951
Ponderosa Pine Mortality Attributed to Bark Beetles*
Aerial Sketchmap Surveys Southwest Oregon 1951 - 2004
and
Average Annual Precipitation at Medford, OR Airport
0
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25000
30000
51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 01 03
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(m
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dead trees detected
precipitation (mm)
Overall average precipitation = 464 mm
* Western pine beetles, mountain pine
beetles and pine engravers
Relationship of precipitation and bark beetle
infestation of pines in SW Oregon
BARK BEETLE MANAGEMENT
STRATEGIES
• Alter bark beetle habitat
- thinning, salvage, stress reduction, non-hosts
• Kill beetles
- sanitation, burning infested, trapping
• Protect trees
- chemical pesticides, pheromones
SILVICULTURAL
MANAGEMENT
Promote host vigor!
Manage stocking levels below thresholds
Thin, under-burn, or both in overstocked stands
Basal Area Thresholds For Elevated Risk of
Pine Bark Beetle Infestation in
Southwest Oregon
Ponderosa Pine - poor to moderate sites = 80 ft²/acre
Ponderosa Pine - high sites = 120 -150 ft²/acre
Sugar or Western White Pines
on Ultramafic Soils = 80 ft²/acre
Sugar or Western White Pines
on Non-Ultramafic Soils = 140 - 180 ft²/acre
Basal area thresholds for bark beetle risk are site dependent
1 acre
Basal area: the cross-sectional area of tree stems
measured at breast height and expressed per unit
of land area [e.g. square feet per acre = ft²/acre]
Thinning across pine
stands or stand
components
Thinning around
individual pines
Tree Crown
Pines Need Space!
Clump of Pines
~same age/cohort
Give the clump space
Pines Need Space!
<13 rings per inch •Higher vigor
•Less susceptible to bark beetles
>13 rings per inch •Lower vigor
•More susceptible to bark beetles
Assessing tree vigor by measuring number of rings per inch (most recent growth)
using an increment core
Second growth ponderosa pine
Non-declining growth rate •Higher vigor
•Less susceptible to bark beetles
Declining growth rate •Lower vigor
•More susceptible to bark beetles
Assessing tree vigor by determining growth rate (most recent growth)
using an increment core
Mature/old growth ponderosa pine
THEN…
1914-1924
<0.5 percent per year
Present
1.0 to 3.0 percent per
year
Ashland Experimental Station
Bureau of Entomology
WHY
Now
MANAGEMENT
Promote host vigor!
Manage stocking levels below thresholds
Thin, under-burn, or both in overstocked stands
Pine Engravers
Manage Slash!!
Options for Pine Engravers
Remove or burn slash before beetles complete life cycle
Reduce risk by treatment design:
- Time thinning appropriately
- Avoid shaded slash piles near hosts
- Lop and scatter slash in the open,
exposing it to the sun
- Pay particular attention to large
diameter slash (> 3 inches diameter)
Using prescribed fire
1997 2010
Plot 8, Survey Pine 436
10 feet
25 feet 25 feet
Control Compressed radius clearing
Extended radius clearing Extended radius large tree retention
N = 58
N = 55
N = 58
N = 58
Based on results so far in the Wolfpine study:
It appears that thinning around large sugar pines contributes to increased
growth, decreases likelihood of bark beetle infestation, and promotes sugar
pine regeneration.
On sites with ridge tops exposed to high winds, stem breakage can be a
sugar pine mortality factor. It seems less of a factor where thinning has
been done with retention of one to several large trees around a large sugar
pine than in unthinned stands or situations where sugar pines are exposed
by themselves in wide openings.
Among treatments, the extended radius clearing with reserve trees retained
shows evidence of being the best for the objective of retaining large old
sugar pines in mixed stands, while at the same time promoting adequate
new sugar pine regeneration.
BARK BEETLE MANAGEMENT
STRATEGIES
• Alter bark beetle habitat
- thinning, salvage, stress reduction, non-hosts
• Kill beetles
- sanitation, burning infested, trapping
• Protect trees
- chemical pesticides, pheromones
WESTERN PINE BEETLE
Dendroctonus brevicomis
• Affects ponderosa pine in two ways
– Scattered mortality in larger trees (>20”dbh)
– Clumped mortality in small diameters
• Strongly associated with drought
conditions or fire damage
• Increased mortality of large & small
ponderosa in recent years (assoc. w/ MPB)
– Long-term damage trends similar
to that of fir engraver
WESTERN PINE BEETLE
What to look for • April-September
– Fine boring dust in bark crevices
– Appearance of small pitch tubes
(1/4-1/2” diameter) on bole
– Pitch tubes may appear multiple
times (2-4 generations/yr)
• September-March
– Foliage of successfully attacked
trees fades (pale green-yellow-orange)
– Attacked trees change from fall to spring
– Woodpecker activity (bark removed) or
presence of beetle gallery (S-shaped
patterns etched into sapwood)
WESTERN PINE BEETLE
Infestation characteristics
• Usually 2 generations per year
– 3-4 possible in southern OR
• Sapwood shows dark staining
– Associated with blue-stain fungus
introduced by beetles
• Operations can increase susceptibility
– Soil compaction or mechanical damage
• Often associated with other beetles
– Pine engraver in upper crown
– Mountain pine beetle on lower bole
– Red turpentine beetle at root collar
WESTERN PINE BEETLE
Management
• Silvicultural
– Thin stands according to site index
recommendations
(See OSU Extension Guide)
• Sanitation and Salvage
– Remove newly infested trees during
winter (contain the most live beetles)
• Individual tree protection
– Spray high-value trees with insecticide
(up to 30’ on stem) prior to spring flight
– Sprays during summer can also reduce attacks
(expensive & requires re-application)
MOUNTAIN PINE BEETLE
Dendroctonus ponderosae
• Endemic / low levels normally occur
• Scattered mortality of often stressed / damaged pines
• Outbreaks initiate in older, overstocked lodgepole stands
• > 60 yr old; Avg. > 6” dbh; Basal area >100 ft2
• 5-needle pines also highly susceptible
• Ponderosa pine usually a more “resistant” host
• Outbreaks continue and intensify (highly variable)
• Sustained by abundance of susceptible lodgepole pines
• Large numbers overwhelm more resistant hosts
• May persist >10 yr and cause significant mortality
MOUNTAIN PINE BEETLE
What to look for • Similar to other pine bark beetles
• Pitch tubes on tree bole
(1/2 - 1” in diameter)
• Rapid foliage change
(off-green / yellow / red)
• Galleries parallel to wood grain
(long 12-36”, J-shaped end)
• Presence of life stages
MOUNTAIN PINE BEETLE
Management in Forests
• Natural controls
• Host depletion
• Severe freeze in fall / spring
• Prolonged cold conditions
• Predators / parasitoids unable
to control outbreaks
• Silvicultural strategies
• Remove infested trees
(containing live beetles)
• Thin overstocked stands
(OSU Extension Guides:
lodgepole vs. ponderosa?)
Clerid beetle
MOUNTAIN PINE BEETLE Management of High Value Trees
• Chemical treatments for individual tree protection
• Bark cover sprays most effective treatment to date
• Systemic applications remain inconclusive
• Variable results with repellent pheromones (Verbenone)
Pheromones
Systemics
Cover spray
PINE ENGRAVERS
Ips spp.
• Hosts include most pines
– Ips pini in Central-Eastern Oregon
– Ips paraconfusus (CA 5-spined Ips)
in western Oregon
• Multiple generations
– 1st generation infests small diameter
down materials (storm breakage, slash)
– 2nd-4rd generation can attack
sapling to pole-sized trees
• Aggressive during drought years
– Long-term trend more variable,
often affects young plantations
PINE ENGRAVERS
What to look for
• March-October
– Orange-brown boring dust in bark
crevices of slash / down wood
– Adult beetle present (spines on abdomen)
– Galleries radiate out from a central
chamber (Y- or H-shaped, 5-10”)
• July-August
– Rapid changes to crown
(yellow to reddish-brown)
– Prefer slash, but if not available
may attack young trees (3-8”dbh)
or cause top-kill in older trees
PINE ENGRAVERS
Infestation characteristics
• Usually 2 generations per year
– 3-4 generations in Southern OR
• Populations build-up in fresh slash or
storm breakage/blowdown
– Following generations cause mortality
– Damage increases when spring moisture
<75% of normal levels
• Operations often linked to damage
– Creating/ abundant >3” dbh slash
during late winter-early summer
– Piling slash in shade or near tree base
PINE ENGRAVERS
Management
• Silvicultural
– Do not leave abundant slash >3” dbh
during the early flight period
– Scatter slash in openings to dry or
dozer-trample/use slash-buster
– Cover / tarp slash piles tightly
– “Green chain” method (create
continual supply of slash)
• Individual tree protection
– Spray high-value trees using
insecticide (up to a 3” top)
– Multiple generations require
re-application (expensive & time-consuming)
BARK BEETLE MANAGEMENT
STRATEGIES
• Alter bark beetle habitat
- thinning, salvage, stress reduction, non-hosts
• Kill beetles
- sanitation, burning infested, trapping
• Protect trees
- chemical pesticides, pheromones
INDIVIDUAL TREE PROTECTION
Protective Cover Sprays
• Only preventative, not curative
• Kills adults as they penetrate bark
• Need proper timing / good coverage
• Registered “ornamental” products in OR
• Carbaryl (Sevin)
• Permethrin (Astro)
• Bifenthrin (Onyx)
• Need experienced applicator
• High-pressure equipment
• Applied to run-off up to 4”
• May need re-application
PROTECTIVE COVER SPRAYS Fettig, et al. 2006
• Objective
• Evaluate efficacy of Bifenthrin (Onyx) and Carbaryl (Sevin)
for protection of high-value Western pines
• Methods
• Cover sprays for MPB, Western pine beetle, and Ips confusus
• Trees baited to initiate attacks (>50% control mortality)
• Findings • High variation but significant
reductions in tree mortality
(Sevin: Avg. 7% mort.; 2-yr protection)
(Onyx: Avg. 20% mort.; 1-yr protection)
• Issues with contract applicators
PROTECTIVE COVER SPRAYS Fettig, et al. 2008
• Objective
• Evaluate drift of carbaryl (Sevin) during protective cover
sprays of individual trees
• Methods
• Assessed drift at 4 distances
(20, 50, 75, 100’) from bole
• Evaluated potential damage
to aquatic species
• Findings • 97% of total spray deposition
remained within 50’ of bole
• Application efficiency approx. 80%
• No-spray buffer of 25’ sufficient for most aquatics
• No-spray buffer of 75’ for more sensitive spp.
• Ongoing evaluations for bark beetles
• Do sufficient levels reach phloem (?)
• High variation by tree species
• Delivered via stem or soil
• Imidacloprid (Pointer, Merit)
• Emamectin benzoate (Tree-äge)
• Requires experienced applicator
• Reduces threat to non-targets
• Potential multi-year protection
• Can be time-consuming and
expensive
INDIVIDUAL TREE PROTECTION
Systemic Insecticides
SYSTEMIC TREATMENTS Grosman, et al. 2010
Emamectin benzoate was effective in providing protection of P. ponderosa
from D. brevicomis during the third year following a single application…These
results are promising, but additional tests are required before we can
conclude that emamectin benzoate is an effective preventative treatment for
any bark beetle – host system.
“To our knowledge, this is the first demonstration of the
successful application of a systemic insecticide for
protecting individual conifers from mortality due to
bark beetle attack in the western United States.”
http://www.fs.fed.us/psw/publications/fettig/psw_2010_fettig(grosman)001.pdf
STRIVING FOR IPM
The Goal
• Natural
• Are natural mortality factors at work or expected?
• Endemic population phase vs. outbreaks?
• Silvicultural
• Tree species, densities, etc. appropriate for site?
• Have contributing factors / stressors been addressed?
• Biological / Chemical
• Are biological products / options recommended?
• What is the relative value of tree or resource?
• Can chemical treatments be used safely / effectively?
CONCLUSIONS
• Pine bark beetles can cause substantial
impacts
• Stands, stand components, or individual
trees that are at high risk are identifiable
• Management treatments exist
• Should be integrated in management
strategies to attain objectives
• Integration with fire and fuels management
STUDY REFERENCES
• Fettig, C.J., K.K. Allen, R.R. Borys, J. Christopherson, C.P. Dabney, T.A.
Eager, K.E. Gibson, E.G. Hebertson, D.F. Long, A.S. Munson,
P.J. Shea, S.L. Smith, and M. I. Haverty. 2006. Effectiveness of
bifenthrin (Onyx ) and carbaryl (Sevin SL) for protecting
individual, high value trees from bark beetle attack in the western
United States. J. Econ. Entomol. 99: 1691-1698.
• Fettig, C.J., A.S. Munson, S.R. McKelvey, P.B. Bush, and R.R. Borys.
2008. Spray deposition from ground based applications of carbaryl
to protect individual trees from bark beetle attack. J. Environ. Qual.
37: 1170-1179.
• D. M. Grosman, C. J. Fettig, C. L. Jorgensen, and A. S. Munson. 2010.
Effectiveness of Two Systemic Insecticides for Protecting Western
Conifers from Mortality Due to Bark Beetle Attack. W. Jour.
Applied Forestry 25(4): 181 – 185
ACKNOWLEDGMENTS
• USDA-Forest Service
• Oregon State University
• Oregon Dept. of Agriculture
• Industrial & Private Cooperators
• Photos: ForestryImages.org, USDA-FS Archives & ODF
*Further Information available from:
Oregon Department of Forestry, Forest Health Unit:
Rob Flowers, Entomologist, [email protected]
Website: http://www.oregon.gov/odf/privateforests/fh.shtml
Oregon State University – Extension Service:
Dave Shaw, Forest Health Specialist, [email protected]
Website: http://extensionweb.forestry.oregonstate.edu/
USDA Forest Service, Forest Health Protection
Bill Schaupp, Entomologist, [email protected]
Website: http://www.fs.usda.gov/goto/r6/foresthealth
Aerial Survey Group, Regions 5&6
And if there is time and/or interest, more
info on other insects of import follows…
WOODBORERS
• Generally secondary agents that
attack dead/dying trees
• Large number of species
– Flatheaded borers (Buprestidae)
– Roundheaded borers (Cerambycidae)
– Wood wasps (Siricidae)
– Pinhole borers - Ambrosia beetles
(Trypodendron, Gnathotrichus spp.)
• Extensive galleries, often extend into
sapwood & heartwood
– Impact wood quality & value
– High-profile non-native species
FLATHEADED BORERS
• Many conifer & hardwood hosts
• What to look for
– Galleries are S-shaped & packed with
fine boring dust in concentric crescents
– Emerging adults leave “D-shaped”
or oval exit holes
– Adults often metallic with short antennae
• Exception: Flatheaded fir borer acts as
a tree-killer in Douglas-fir
– Attacks mature trees on low-elevation,
drought-prone sites
– Fire damaged trees very susceptible
Flatheaded fir
borer
(Phaenops
drummondi)
Public
Enemy
Number One!
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Douglas-fir Mortality Attributed to Flatheaded Fir Borer Annual Aerial Sketchmap Surveys 1974 - 2011
and Annual Precipitation 1971-2010
Medford International Airport, Medford, OR
Number of dead trees detected Annual Precipitation Average Annual Precipitation
ROUNDHEADED BORERS
• Many conifer & hardwood hosts
• What to look for
– Larval galleries are S-shaped & loosely
packed with coarse boring materials
– Emerging adults leave circular exit holes
– Adults usually have long antennae
(also called “longhorn” beetles)
• Native woodborers often confused
for non-native species
– Fir sawyer & Banded alder
borer (right) often mistaken
for Asian longhorn beetles (left)
WOOD WASPS (Horntails)
• Many conifer & hardwood hosts
– Tunnel through sapwood & heartwood
– Larvae have spine on tip of abdomen
– Adults wasp-like with projection on
abdomen (longer on females)
• Non-native wood wasp (Sirex noctillio)
of increased concern
– Significant damage when introduced
to new areas
– Recently detected in Eastern US
– Trapping & monitoring underway
in Western US
AMBROSIA BEETLES
• Many conifer & hardwood hosts
– “Pinhole” tunnels & dark staining
in sapwood
– Abundant fine boring dust produced
– Do not feed on wood, but construct
tunnels for growing fungus
– Adults are very small (2-5 mm)
• Greater damage in wetter/coastal
areas of Oregon
– Can quickly degrade wood quality
– Often survive pre-export treatments
(Potential invasive species)
INVASIVE SPECIES: CURRENT EFFORTS
• Oregon Invasive Species Council,
– “100 Least Wanted” published annually
• ODA Trapping & Inspections
– Gypsy moth, Nun moth & Japanese
beetles (pheromone traps)
– Asian longhorn beetle & European
wood wasp (surveys & inspections)
– Emerald ash borer (trap trees, traps)
– Granulate ambrosia beetle (traps)
• No detections in 2011 in OR
– Recent gypsy moth eradication projects
in Bend, Shady Cove, & Eugene