Some New

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Some New ( Old) Tree Insects

• Bob Hammon
• Tri River Area Extension
• Grand Junction

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• Banded Elm Bark Beetle
• Twig beetles in Conifers
• Walnut Twig Beetle /
• 1000 Cankers Disease
• Aspen/Poplar/Willow Scale

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CAPS Exotic Wood Borer Survey
Orthotomicus erosus Mediterranean Pine
Engraver Hylurgus ligniperda Goldenhaired Bark
Beetle Ips typographus European Spruce Bark
Beetle Tomicus piniperda Pine Shoot
Beetle Sirex noctilio European Wood
Wasp Agrilus planipennis Emerald Ash
Borer Anoplophora glabripennis Asian Longhorn
Beetle A. chinensis Citrus Longhorn Beetle
CAPS has been very good for cataloguing our
native fauna
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Banded elm bark beetle Scolytus schevyrewi

• Identified from CO in 2003
• Abundant in western CO
• CAPS survey side-capture
• Elms other hardwoods

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S. schevyrewi

• Host plants
• Elm
• Russian olive
• Prunus
• Willow
• Scolytis
• Apex of elytra extends beyond abdomen

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S. schevyrewi Life History

• Overwinter as mature larvae
• 2-3 generation/year in GJ
• Adults present Jun Oct

Adult beetles feed on bark near twig crotches
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Females bore into trunk and construct egg
galleryMales enter gallery and mate
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Female chews egg niches along gallery and lays
individual egg in eachNiches are filled with
sawdust Usually gt60 egg per female
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Larval galleries are initially perpendicular to
egg gallery, but eventually turn up or down
Galleries may cross
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Pupation within feeding gallery
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Bark Beetle Damage
Feeding Galleries
What You See
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You Can Help

• We are interested in host records in trees other
  than elm
• Prunus
• Apple/crabapple
• Willow

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Twig Beetles

• Pines
• Walnut twig beetle/1000 Cankers Disease

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Ips vs Twig beetle
Parts of trees Outside-in
Whole tree/branch All-at-once
The pinyon Ips outbreak is over, twig beetles are
still a threat
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Twig Beetles
Damage on smaller twigs Larvae feed under
bark Adults seldom seen Control timing similar to
Ips
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Adult Twig Beetles
Adults are tiny About 1 mm long Early
generations appear to be synchronized 0-0-0-3500-
0-0-0
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Diagnosing Twig Beetles in Pine
Damage on small twigs Round exit holes lt2 mm
diameter Larval feeding damage under bark peel
with knife
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Controlling Twig Beetles

• Keep the trees healthy!!!
• Pyrethroid sprays can prevent infestations
• Larval feeding is close to surface
• pyrethroids can be used for rescue
• Neonicitinoids have a place in control
• Soil drench
• Trunk injection
• Trunk drench

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Walnut Twig Beetle and 1000 Cankers Disease
Whitney Cranshaw Ned Tisserat Curtis Utley
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Thousand Cankers Disease An Insect/Fungal
Disease Complex Affecting some Juglans spp.
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Unexplained decline of black walnut in Colorado
has been observed since about 2001
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Walnut decline hot spots in Colorado - 2008
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In affected trees there is an associated twig
beetle the walnut twig beetle (Pityopthorous
juglandis)
First records of this insect from Colorado were
established in 2004 (Boulder, Westminster)
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The walnut twig beetle is a minute bark
beetle. It is one of few Pityophthorus species
that develop in hardwoods. Pityophthorus bark
beetles are collectively known as twig beetles
because they normally restrict damage to small
diameter twigs.
Jim LaBonte, OR Dept. Agriculture!
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Other Recent New State Records for Walnut Twig
Beetle

• Idaho 2004 record associated with die-off of
  black walnut in Boise-Meridian area (Frank
  Merickel)

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Other Recent New State Records for Walnut Twig
Beetle

• Idaho 2004 record associated with die-off of
  black walnut in Boise-Meridian area (Frank
  Merickel)
• Utah Widespread die-off occurred in late 1990s
  in Provo area. State records from that time
  period (1996). State record of a single beetle
  August 22, 1988 from Provo. (Shawn Clark, Diane
  Allston)

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Other Recent New State Records for Walnut Twig
Beetle

• Idaho 2004 record associated with die-off of
  black walnut in Boise-Meridian area (Frank
  Merickel)
• Utah Widespread die-off occurred in late 1990s
  in Provo area. State records from that time
  period (1996). State record of a single beetle
  August 22, 1988 from Provo. (Shawn Clark, Diane
  Allston)
• Oregon Common in 2004 traps samples in the
  Dalles area. Review of samples identified 1997
  sample from Portland (Jim LaBonte)

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Other Recent New State Records for Walnut Twig
Beetle

• Idaho 2004 record associated with die-off of
  black walnut in Boise-Meridian area (Frank
  Merickel)
• Utah Widespread die-off occurred in late 1990s
  in Provo area. State records from that time
  period (1996). State record of a single beetle
  August 22, 1988 from Provo. (Shawn Clark, Diane
  Allston)
• Oregon Common in 2004 traps samples in the
  Dalles area. Review of samples identified 1997
  sample from Portland (Jim LaBonte)
• WA Recovered from Prosser area

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Since 1992 there have been new state records for
the walnut twig beetle in many western states
CO, UT, ID, OR and, in 2008, WA
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Most all of these new detections of walnut twig
beetle have been associated with black walnut
die-offs.
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Where did it come from?
Arizona walnut (Juglans major) Host associated
with original descriptions of the walnut twig
beetle
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Distribution of Arizona walnut
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J. major common in canyons and along riverways
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In Arizona walnut the insect acts as a typical
twig beetle
Dieback of lower, shaded branches
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In Colorado black walnut, beetles regularly
attack all diameter branches and are even found
in the trunk.
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Trees typically die within three years after
initial symptoms of leaf yellowing and dieback
are first detected.
Dark cankers are present in phloem limbs
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Massive trunk cankers are observed in end
stages These large cankers are in the cambium
area
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The Big Question

• How can a little twig beetle be killing healthy
  trees???

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Geosmithia sp. fungus associated with the twig
beetle Fusarium
associated with lesions
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• 1000 Cankers Disease
• The Geosmithia fungus is carried into the tree
  when the beetles feed in bark
• The fungus produces small cankers in the area
  around its introduction by the twig beetle
• Both twig beetle and fungus act very
  aggressively in black walnut
• Twig beetles can be present in huge numbers
• Massive numbers of cankers girdle the trees
  leading to dieback and decline.

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Walnut twig beetle life cycle in Colorado?
Spring colonization by adult beetles occurs in
late April and early May
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Walnut Twig Beetle Captures in Yellow Sticky
Traps. Boulder, 2006
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Patterns of attack

• Base of twigs, rough areas of bark frequent
  points of entry
• Underside of branches preferred
• Possible orientation of trunk attacks

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Larval development takes about 6-8 weeks to
complete. There are probably two generations per
season.
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At the end of the summer, beetles move into the
trunk to spend the winter in chambers excavated
in the bark. This is where they are now!
Jim LaBonte
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Twig Beetle Management?

• Drenching branch sprays
• Soil-applied systemic insecticides
• Late summer trunk treatment

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Spread of walnut twig beetle through the western
states involves human transport of infested wood
products
Long distance movement of walnut wood killed by
1000 cankers disease will be a huge issue due to
the high value of the saw logs
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Drenching branch sprays for walnut twig
beetle Pyrethroids with residual Timing based
on trap captures Early summer?
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• Neonicitinoid soil drenches/injections?

The fungus grows ahead of the beetle. Cankered
areas may prevent movement of insecticide to the
beetle feeding site.
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Soil treatments and Walnut Twig Beetle - Anecdotes

• Imidacloprid may assist in prevention or slowing
  spread of walnut decline if it is applied
  prophyllactically
• Dinotefuran may work better for this application

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Does the overwintering hibernation habit provide
a point for management?
Management of walnut twig beetle using the
management model for the native elm bark beetle.
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Establishing the distribution of 1000 cankers
disease in CO Has anyone seen this in western CO?
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This information gleaned from many people
including Whitney Cranshaw Curtis Utley, Ned
Tisserat, Don Bright, Dave Leatherman, Kathleen
Alexander, Steve Seybold.
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The Aspen ScaleAKA Willow ScaleAKA Poplar
ScaleDiaspidiotus gigasAKA Quadrispidiotus
gigasAKA Aspidiotus (Euraspidiotus) gigas
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Many thanks to
Vince Urbina Colo St Forest Service Chris
Forman City of Aspen CO Todd Mayhew Valent
Corp Ed Berkheimer Earth-Wise Horticultural
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The Situation

• Found attacking street side trees in Aspen CO in
  2006
• Detected in Durango, CO aspen cottonwood in
  2007
• Present in Sun Valley, Haley, Ketchum ID in
  2007
• Vail, Carbondale CO 2008
• Limited occurrence in natural stands

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Most incidence in urban street plantings Appears
in high stress situations
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Often an association with wooly aphids (at least
in Aspen)
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Natural stands, Ketchum ID
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Not Part of Sudden Aspen Decline
Predisposing factors Mature forests S W
Aspect Inciting factors Drought Other
stress Contributing factors Cytospora
canker Borers Bark beetles
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Tree Damage in ID
Bark death
Bark pitting
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Bark splitting on Narrowleaf Cottonwood
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D. gigas Identification

• Id by
• Dr Whitney Cranshaw (Colo St Univ)
• Dr. Ferenc Kozar, Hungarian Acad of Sci.
• Dr Greg Hodges, Fl Dept of Agric
• Dr Doug Miller, USDA
• All agree on Diaspidiotus gigas

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Aspen Scale Appearance

• Armored (hard) scale
• ? cover circular
• 2mm diameter
• Moderately convex
• Gray
• Orange-yellow center
• Ventral aspect

Top
Bottom
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• Soft Scales
• secrete an attached, thin, waxy layer over
  themselves.
• soft covering cannot be separated from the
  scale's body.
• typically move between branches and leaves during
  lifecycle.
• produce honeydew.
• Armored (Hard) Scales
• use shed skins and wax that is unattached to
  their body to form their hard, shell-like cover.
• covers can be separated from the scale's body.
• do not move to leaves during their lifecycle and
• not produce honeydew.

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Armored (Hard) Scales
Soft Scales
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Soft Scales Include Pine Tortoise Scale,
Striped Pine Scale, European Elm Scale, Cottony
Maple Scale
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Like aphids, soft scales suck sap from the phloem
and excrete honeydew.
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European elm scale produces large amounts of
honeydew. Where it lands and persists, sooty
molds grow.
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Soft Scales Armored Scales
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Armored Scales Include Oystershell Scale, Pine
Needle Scale, Walnut Scale and others
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Black Pineleaf Scale
Pine Needle Scale
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Imidacloprid Control Range
Yes
No
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Safari (Dinotefuran)

• Neonicotinoid insecticide
• Primarily labeled to control insects that suck
  sap (Order Hemiptera)
• Aphids
• Soft scales
• Armored scales
• Has systemic activity in plants
• Apparently more mobile in plant than other
  neonicotinoids

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Relative Water Solubility of Neonicotinoids
Water Solubility (Active Ingredient)
Milligrams A.I./ liter
Information sources Clothianidin (Celero),
Acetamiprid (Tristar), Dinotefuran (Safari) EPA
Pesticide Fact Sheet Imidacloprid (Marathon),
hiamethoxam (Flagship) MSDS for Products
Slide information courtesy J. Chamberlin
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San Jose ScaleDiaspidiotus perniciosus

• Polyphagous
• Likes Rosaceae
• Destructive to fruit trees
• Widespread in US
• Similar to D. gigas

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Oystershell scaleLepidosaphes ulmi

• Widespread in US
• Wide host range
• Populus
• Ash
• Willow
• Dissimilar to D. gigas
• often confused

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Aspen vs Oystershell
Oystershell
Aspen
Top Bottom
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The morphology, metamorphosis, and the life cycle
of the scale insect Quadraspidiotus
gigasLellakova-Duskova, 1963Acta Entomol. Mus.
Nat. Prague

• 4 year study in Czechslovakia
• Preferred smooth bark areas on trunks thick
  branches
• One generation per year
• 2nd instar males and females overwinter
• Transferred to Tilia cordata, Ulmus scabra,
  Fraxinus excelsior
• Eggs in late June to early Sep

Scale Insects of Central Europe Kosztarab Kozar

• One generation per year

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Armored Scale Insect Pests of Trees and
ShrubsMiller Davidson

• Probably native to Europe
• Restricted to Salix Populus in US
• Specimens from ID, MT, OR, UT, WA, WY in western
  US

Scale Insects of Northeastern North America
Kostarab, 1996

• NY, OH, PA, RI, WI, central western US, Canada,
  Europe
• Can cause deformation on bark and death of
  branches when infestations are severe.

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• Aspen Scale
• Natural History Observations
• Overwinters as mature female
• Eggs? Crawlers?
• Males present in spring
• Other times also?
• Crawlers present in winter
• Year round?
• Multiple overlapping generations

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D. Gigas in February (Aspen CO)
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Overwintering forms in Aspen CO Mature (?) Female
Crawler (?)
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Male ??
Common, according to lit April 13, 2007 Growth
stage ???
Winged males caught on sticky tape Mid/late May
to early June
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Coccinellid Eggs?
Early spring 2007, not difficult to find
Winter 2008. a few at one site. Small orange dots
are crawlers, eggs larger than crawlers
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Scale Parasitoids
Exit holes in scale covers Ketchum ID Have not
seen in CO
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Parasitoid Poop!
Black fecal pellets from ectoparasitic wasp
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Controlling the Aspen Scale

• Safari (dinetofuran)
• 12 gm/in DBH
• May application
• Expensive
• Oil
• Spring (pre leaf) and
• Fall (pre color/color) applications
• Best on low/moderate infestations

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Aspen Mites

• A perennial problem in Aspen CO
• ID unknown
• Symptoms are black spotting / leaf drop
• Present from leaf flush to leaf drop
• Many sprays used
• Abamectin, Neem, Floramite, Tetrasan
• Merit flares them!

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2008 Research

• Safari, Safari 2G
• 3,6,9,gm/ DBH, soil injection
• Leaf flush/expansion and 4 wk later
• No scale morality
• Gallonage?
• Rate?
• Research in cooperation with Valent, City of
  Aspen

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Thank You!

• Bob Hammon
• Colorado State University
• Tri River Area Extension
• Grand Junction CO
• bob.hammon_at_mesacounty.us
• http//wci.colostate.edu