Cranshaw. Management of Wood Boring insects

Management of
Wood Boring
Insects
Whitney Cranshaw
Colorado State University
Several Insects Work as Borers
• Some beetle larvae
– Flatheaded borers/Metallic wood borers
– Roundheaded borers/Longhorned beetles
• Some moth larvae
– Clearwing borers
– Carpenterworms
– Pyralid borers
• Some wasp larvae
– Horntails
Flatheaded Borers/
Metallic Wood Borers
Coleoptera:
Buprestidae
Flatheaded Borer
Thinning of the crown is a
common symptom of
flatheaded borer infestation
Pupation occurs under the bark
Photo sequence by David Shetlar, Ohio State University
D-Shaped Exit Hole Produced by Emerging Metallic Wood Borer
Metallic Wood Borer,
Adult Form of a
Flatheaded Borer
Metallic Wood Borer
- Adult form of a
Flatheaded Borer
Some metallic wood
borers have bright
coloration
Four Agrilus sp. Borers
found in Colorado
Top Row - Rose stem girdler (left), Bronze birch
borer (right)
Bottom Row – Honeylocust borer (left), Gambel
oak borer (right)
D-Shaped Exit Hole Produced by Emerging Metallic Wood Borer
Diagnosis – Flatheaded
Borer Injury
• Meandering tunnels produced
under the bark
–Tunnels packed with fine sawdust
• Plant shows decline/thinning
crown
• D-shaped exit holes in bark
Roundheaded Borers/
Longhorned Beetles
Coleoptera:
Cerambycidae
Pine Sawyers
Cottonwood Borer
Banded Alder Borer
Locust Borer
Poplar Borer
Dave Leatherman
Ponderous Borer
Dave Leatherman
Roundheaded Borer
Coarse sawdust expelled from
tree by roundheaded borer
Locust Borer tunneling
Photographs by David Leatherman
Life stages of a
poplar borer
Photograph courtesy John
Ghent/IPM Images
Diagnosis – Roundheaded
Borer Injury
• Tunneling penetrates into
heartwood of the tree
–Riddling, structural weakening
• Coarse sawdust typically
produced
• Oval exit holes in bark
Clearwing Borers
Lepidoptera: Sesiidae
Some Common Clearwing
Borers of Colorado
•
•
•
•
•
•
Peach tree borer (Prunus spp.)
Lilac/Ash borer (ash, lilac, privet)
Currant borer (Ribes spp.)
Viburnum borer (Viburnum spp.)
Raspberry crown borer (raspberry)
Cottonwood crown borer (Cottonwood)
Peach tree borer larval
tunneling in base of plant
Top: Peach tree borer larva
Right: Prolegs on the abdomen,
tipped with hooked crochets, are
characteristic of borers that develop
into moths (Order Lepidoptera)
Small hooks on the underside of the abdomen
(crochets) indicate the larva is a type of moth.
Beetles do not have prolegs on the abdomen
with these hooks.
Upper left: Peach tree borer female
Upper right: Peach tree borer male
Lower left: Pupal skin extruded from
case of silk and wood fragments
Raspberry crown borer larva in base of raspberry
Raspberry crown borer adults –
mimics of yellowjacket wasps
Lilac/Ash borer adult – mimic of a paper wasp
Lilac/ash borer injury to base of ash - exterior
Lilac/ash borer damage to base of ash -interior
Lilac/ash borer larvae
The pupal skin often
extrudes when the
adult emerges
Exit holes are slightly oval, nearly round
Lilac/Ash Borer Mating Pair
Diagnosis – Clearwing
Borer Injury
• Tunneling often concentrated
at the base (root crown) of the
plant
• Tunneling an irregular gouging
• Pupal skins often are pulled out
upon adult emergence
Wood Borer Management
• Optimize conditions for
plant growth
• Sanitation
• Preventive applications of
insecticides
Plant Health Care and Wood
Borer Prevention
• Proper selection of plant material
• Appropriate siting in the landscape
• Good site preparation, planting
conditions
• Provision of adequate
watering
Note: Fertilization can produce mixed effects on borer resistance
Example: Birch and
bronze birch borer
Wood Borers and Plant Stress
• Plant defensive responses are
diminished
–Related to stored photosynthate
and water availability
• Plants may be slightly more
attractive to adults when they
lay eggs
Sanitation and Wood Borers
• Elimination of potential brood
wood
• Prune-out of infested wood
Proper disposal of
infested wood is
important.
Preventive Use of
Insecticides
Treatments are not
available for borers
currently in a plant
Preventive Use of
Insecticides
Timed for Egg
Laying/Egg Hatch
Period!
Evidence of adult
borer activity –
observation of the
adults on plants
Evidence of borer
adult activity –
fresh exit holes
Evidence of
clearwing borer adult
activity – new pupal
skins
For most borers flight
periods can be estimated
Fact Sheet 5.530
(Borers) or Bulletin
506A
Approximate flight periods of
some wood borers
• Lilac/Ash borer
– early May
• Bronzed birch borer (and other Agrilus spp.)
– mid-June
• Poplar borer
– late June
• Peachtree borer
– early July
• Locust borer
– mid-August
Pheromone Traps – A tool for monitoring some insects
Pheromones and Insect
Management
• Pheromones are chemicals used to
communicate between members of the
same species
• Insects use many kinds of pheromones
– Sex
– Aggregation
– Alarm…… and many other things
• Sex pheromones of some moths are
used in pest management
Pheromone trap
data for lilac ash
borer
Active Ingredients of Wood
Borer Insecticides
•
•
•
•
•
Permethrin (Astro, etc.)
Carbaryl (Sevin)
Bifenthrin (Onyx, Talstar, etc.)
Acelypryn
Imidacloprid
– Soil applied drench
Key Timing Point in Wood
Borer Prevention
Egg Laying/Egg Hatch
(Coincident with adult activity)
Acelepryn
• New class of insecticides –
anthrinilic diamides
– Derivatives of ryania (natural product)
• Activity against most chewing
insects
• Labels being developed for both
turfgrass and woody ornamentals
Acelepryn
• Very low toxicity to vertebrates
–LD50 greater than 5000 mg/kg
• Class 4 – No Caution label
• Protective equipment
–Long sleeved shirt, long pants
–Shoes with socks
Acelypryn labeled use – Lace bugs (soil treatment)
Acelypryn labeled use – Caterpillars (foliar treatment)
Acelepryn labeled use –
clearwing borers (trunk
spray)
Future of Acelepryn?
• Low risk a huge plus
• Soil-applied systemic activity a huge
plus – but poorly understood
• Activity probably includes most leaf
chewing insect groups
• Activity as wood borer treatment very
good (clearwing borers…and others?)
Active Ingredients of Wood
Borer Insecticides
•
•
•
Permethrin (most available)
Carbaryl/Sevin (limited availability)
Bifenthrin (no over-the-counter products at
present)
• Imidacloprid
– Soil applied drench - systemic
insecticide
– Only effective against
flatheaded borers
Imidacloprid for Borers?
Yes…..but
Imidacloprid will not
work well on borers
that are the larval
stage of moths (i.e.
insect order
Lepidoptera)
Peach tree borer larval
tunneling in base of plant
Zimmerman
pine moth
injury
Imidacloprid soil
drenches will work
poorly against
roundheaded borer
larvae that spend little
time in cambium
Imidacloprid soil
drenches will work
poorly against
flatheaded borer
larvae after they have
caused extensive
damage
Imidacloprid soil
drenches may work
well against
flatheaded borer
larvae (aka metallic
wood borers) – if the
plant has not already
been badly damaged
Four Agrilus spp. borers
Top Row - Rose stem girdler (left), Bronze birch
borer (right)
Bottom Row – Honeylocust borer (left),
Emerald ash borer (right)
Dan Herms
David Cappaert
Some Currently Used
Neonicotinoid Insecticides
• Imidacloprid (Merit, Marathon,
Criterian, Provado, Admire - many generics)
• Clothianidin (Celero, Arena, etc.)
• Dinotefuran (Safari)
Relative Water Solubility of Neonicotinoids:
Water Solubility (Active Ingredient)
500
0
Slide information courtesy J. Chamberlin
2950
4100
39830
Dinotefuran
327
Thiamethoxam
10000
Acetamiprid
20000
Imidacloprid
30000
Clothianidin
40000
Koc Values of Neonicotinoids:
Source Data: EPA Pesticide Fact Sheets
Dinotefuran
0
245
Thiamethoxam
267
Acetamiprid
Clothianidin
166
Imidacloprid
440
26
Implications for Dinetofuran
(Safari) Soil Applications
• Dinotefuran requires moist soils
for uptake
– Can move through thin bark
• Uptake into plant is relatively fast
– Ability to control aphids in days
• Persistence in plant much shorter
than other neonicotinoids
Safari trunk sprays have
been developed as a tool to
manage emerald ash borer
Bark Beetles
Coleoptera: Curculionidae
(Scolytinae)
Mountain Pine Beetle
Dendroctonus ponderosae
Western Pine
Beetle
Photograph courtesy of Ladd Livingston/IPM
Images
Friday Seminar – 9:00
What’s Happening in
Idaho’s Forests
Carl Jorgenson
USDA Forest Service
Thousand
Cankers
Disease (TCD)
– An Insect/Fungal
Disease Complex
affecting some
Juglans spp.
A beetle – walnut
twig beetle
A fungus –
Geosmithia
morbida
Jim LaBonte
Walnut Twig Beetle
Pityophthorous juglandis
Jim LaBonte
Adults enter trees
and excavate
galleries
Larval feeding produces a loose network of meandering
tunnels in the cambium
A full grown larva, preparing to pupate.
Teneral adults and pupa, covered with Geosmithia spores
The Pathogen - Geosmithia morbida
Geosmithia is
introduced into
wounds made by
walnut twig beetles
Growth of the fungus beyond the inoculation site
creates a dead region (canker) in the cambium.
Multiple cankers produce girdling that seriously
restricts movement of nutrients.
Flagging symptoms
emerge in end
stages of 1000
cankers on black
walnut
Foliage wilting may occur rapidly on TCD-compromised limbs
Crown symptoms July 2009 – Tree died in 2010
September 2008
June 2008
June 2009
Death by TCD – Working
Hypothesis
Walnut twig beetle exit holes
• Girdling from cankers (and bark beetle
tunneling) restricts movement of
nutrients.
• Trees weaken as stored energy
reserves become depleted.
– External symptoms develop in end stages
of infestations
• Trees ultimately die from energy
depletion.
Symptoms of Thousand
Cankers Disease
develop following
sustained introductions
of Geosmithia by walnut
twig beetles in
susceptible hosts.
Origin of Thousand
Cankers Disease
The walnut twig beetle
was originally described
(1928) from Arizona
walnut, Juglans major.
Great picture by Jim LaBonte,
OR Dept. Agriculture!
Original collections of the
beetle were made in 1896.
Published distribution of Arizona walnut
Arizona walnut (Juglans major) – Host associated with
original descriptions of the walnut twig beetle
Arizona walnut is a common species found in canyons
and along riverways
In 2008-2009 surveys, walnut twig beetle was repeatedly
found in Arizona walnut at several sites in NM and AZ
Walnut twig beetle in AZ walnut
functions as a “typical”
Pityophthorus species of twig
beetle. Attacks are normally
limited to small diameter
branches and function as a
form of natural pruning.
Progression to fullblown Thousand
Cankers Disease has
not been observed in
AZ walnut.
Geosmithia morbida is
also likely to be a native
fungus.
The Geosmithia fungus
is has been found
consistently
associated with the
tunnels and frass of
walnut twig beetles –
regardless of Juglans
spp. or site of
collection.
Resistance to
Thousand Cankers
Disease may often
result from
differences in
susceptibility to
Geosmithia morbida
Canker formation in
black walnut
Canker formation in
Southern California
walnut
How did this happen?
- Somehow the beetle jumped hosts.
Walnut Twig Beetle Range
Expansion
“Big Bang” or
“Buttheads”
Spread of walnut twig
beetle through the
western states
involved human
transport of infested
wood products
States reporting presence of walnut twig beetle -2009
Native Distribution of Black Walnut,
Juglans nigra
What I said last spring…….
Good News: Walnut twig
beetle has likely not yet
reached the native range of
Juglans nigra (we think).
July 20, 2010 – Very, very bad news:
Thousand cankers and walnut twig beetles
found in the center of the native range of
Juglans nigra
Knoxville, Tennessee
Note: The local
foresters thought that
the trees were
suffering from
drought stresses
Thousand Cankers
has now breached the
geographic barrier of
the Great Plains!!!!
Implications of TCD Finding in
Native Range
• There are now no ecological or geographic
barriers that will prevent TCD spread
throughout the entire range of Juglans nigra
– Natural spread will be slow (comparably) but
inexorable
• Containment through restrictions on
movement of walnut wood products may
slow spread
• Aggressive management at edges of
infestation may slow spread
Slow the Spread of Thousand Cankers Disease!
Good News: Other Juglans species are
not as susceptible to TCD as is Juglans
nigra (black walnut). Pecan (Carya) are
apparently TCD resistant.
Good News: It takes a long
time (Decade? More? A bit
less?) for a tree to die
following initial colonization
by walnut twig beetles.
Bad News: By the time symptoms appear it can
be assumed that the walnut twig beetle is
generally distributed in the area.
Bad News: Prospects
for effective chemical
control of walnut twig
beetle are poor.
Drenching branch
sprays for walnut
twig beetle
Treatments have failed
to slow progress of
thousand cankers in
trees showing
symptoms
Systemic insecticide soil drenches/
trunk injections?
The fungus grows ahead of the beetle.
Cankered areas may prevent movement of
insecticide to the beetle feeding site.
Thousand Cankers Management &
Pesticides
What kind of crop is
black walnut?
Pesticides Used on Black Walnut Must
be Consistent with Labels for Nutbearing Crops
• Probably legal
– Imidacloprid
– Chlothianidin
• Not apparently legal for use on black
walnut
– Dinotefuran
– Abamectin
– Enamectin benzoate
Bad News: Prospects
for effective control of
walnut twig beetle are
poor. Insecticides
may slightly slow, but
will not stop the
progress of TCD.
Bad News: Walnut wood
with bark intact is
extremely infectious.
Two logs, ca 5 1/2-in diameter, 18-in length
23,040 Beetles/2 logs
= 35+
Beetles/inch2
Bad News: 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.
What about chipping?
Walnut twig beetles
were able to complete
development in larger
pieces following
chipping
A walnut log in Denver waiting for Uncle Benny from
Chicago
Beetle infested black walnut from Boulder area with bark
attached as advertised on the internet
What Needs to Be Done
• Strong public education on the threat
of Thousand Cankers Disease to black
walnut in its native range
• Immediate restriction, aided by national
quarantine, of all Juglans material that
may spread walnut twig beetle into the
native range of black walnut.
Immediate Action Needed:
Institute quarantine of all Juglans
wood of where thousand cankers
is present
X
A Juglans Quarantine
• Would affect logs/wood with bark
intact
• Would not need affect
– Milled wood without bark
– Logs that have sufficiently dried so live
beetles cease production (3 years?)
– Kiln-dried wood (questions remain about
reinfestation potential)
– Nuts
States with Existing or Proposed
TCD Quarantines
• Missouri
• Iowa
• Kansas
• Wisconsin?
• Michigan
• Indiana
• Nebraska
• North
Carolina
Slow the Spread of Thousand Cankers Disease!
TCD Training Workshops – Many states are
now trained in TCD diagnosis
An Interim Web Site for TCD information
Department of Bioagricultural
Sciences and Pest Management
Colorado State University
Click on “Extension and Outreach”