Advances in Understanding Ambrosia Beetle Chemical Ecology

Jason Oliver1, Chris Ranger2, Mike Reding2, and Pete Schultz3

1 Tennessee State University, School of Agriculture and Consumer Sciences,Otis L. Floyd Nursery Research Center, McMinnville, TN

2 USDA-ARS, Horticultural Insects Research Laboratory, Wooster, OH3 Virginia Tech, Hampton Roads Center, Virginia Beach, VA

Advances in Understanding Ambrosia Beetle Chemical Ecology and Utilizing the Findings to Improve Insecticide Management

2.0 mmUSDA-ARS, Wooster

Outline

1) General Biology and Information

2) Research

3) Management Issues / Options

TrappingInducing Tree AttacksInsecticide StudiesPlant Stress Studies

Subfamily Scolytinae

Ambrosia, Bark Beetles, and Engravers

~ 5,812 species worldwide

- Many are attracted to volatiles probably related to plant stress (e.g., ethanol)

Ethanol Lure Pack

Theysohn (“slot”)LindgrenFunnel

Vane Panel

- Dark silhouettes

Ambrosia Beetles

24 Species Trapped at Tennessee Nursery Center (1998 / 1999)

Granulated (Asian) Ambrosia Beetle(Xylosandrus crassiusculus [Motschulsky])

Actual Size

Lesser Shothole Borer, Fruit-Tree Pinhole Borer(Xyleborinus saxeseni Ratzeburg)

Black Stem Borer, Smaller Alnus Beetle, Tea Root Borer(Xylosandrus germanus Blandford)

Species Attacking Nursery Stock in Tennessee

Thysanoes fimbricornis LeConte


- Numerous reports of damage across eastern U.S.

- Introduced to South Carolina in 1974

- Now widely distributed

Granulated Ambrosia Beetle (“Asian AB”)

5 – 10 GAB will kill most trees under 3 inch caliper (Mizell and Riddle 2004)

- Seems to be more problematic in northern states

- Introduced at Long Island New York about 1932

- Now widely distributed

Black Stem Borer

- Multiple reports of being problematic in walnut production


CherryChestnutElmMapleOakPersimmonSweetgumBuckeyeCrape myrtleDogwoodFig

Golden raintreeMagnoliaPeachPearPecanPersimmonPlumRedbudStyraxSweetgum

Major HostsCherryChestnutElmMapleOakPersimmonSweetgumAlderAppleBeechCypress

GrapeHickoryHornbeamMulberryPineRhododendronSpruceTulip poplarTupeloWalnut

Major Hosts

Over 100 known hosts Over 34 plant genera hosts

Walnut???


Lesser Shothole Borer, Fruit-Tree Pinhole Borer(Xyleborinus saxeseni Ratzeburg)

Black Stem Borer, Smaller Alnus Beetle, Tea Root Borer(Xylosandrus germanus Blandford)

Ambrosia Beetles Reported as Problematic on Walnut

Pear Blight Beetle, European Shot-Hole Borer(Xyleborus dispar [Fab.])

Cosmopolitan Ambrosia Beetle, Black Twig Borer(Xyleborus ferrugineus [Fab.])

Oak Timber Beetle(Xyleborus xylographus [Say])

J.R. Baker & S.B. Bambara,NCSU, Bugwood.org

Pest & Disease Image Library, Australia, Bugwood.org

Pest & Disease Image Library, Australia, Bugwood.org

(Solomon 1995)

Importance: Most have broad host ranges, primarily preferring hardwoods

Range: Most introduced from Asia or Europe and occur over most of U.S.

Habits: Adults usually over-winter in galleriesFemales mate before leaving galleries. Males do not fly.Bore into sapwood, usually not the heartwood.Galleries consist of branches or enlarged brood chambersLarvae and adults feed on symbiotic ambrosia fungusAdults “culture” fungi along gallery wallsSome continue to extend galleries over timeSome begin galleries and are then joined by others of their speciesSome have one generation per year and others have multiple

Peak Activity: Emerge as early as February (X. saxeseni), but usually peak emergence is March through May

Host Preference: Unthrifty, injured, and dying trees. Moisture contentimportant. Attracted to stressed trees.

Generalities Among Walnut Attacking Ambrosia Beetles

Damage: Prefer to attack before “bud-break”Wilting, flagging, branch dieback, basal sprouts, tree deathLumber staining and reduced quality from galleriesPossible vectors of other pathogenic fungi

Generalities Among Walnut Attacking Ambrosia Beetles

Control: Natural enemies (predaceous beetles / true bugs)Cultural practices promoting healthy treesPrompt harvest and use of timberSeed sources listed as important for X. germanus (Weber)Plantings near water sources may be more susceptibleTraps to time judicious insecticide treatments

Shot holes

- Adult boring produces “shot holes”

- Boring activities can result in “sawdust” or “toothpick” like particles

- Tunnels (galleries) generally made deep into sapwood

1 inch

Granulated Ambrosia Beetle Gallery

- Adults carry species-specific symbiotic “ambrosia” fungus in mycangia

Doug Stone, Miss. St. Univ.,Bugwood.org

Jack C. Nord, USDA For.Serv.www.forestryimages.org

- Larvae and adults eat ambrosia fungus

Doug Stone, Miss. St. Univ., Bugwood.org

- Female progeny emerge from host trees and fly to new host trees

- Males do not fly, but will exit trees

- Ambrosia beetles are more serious nursery and landscape peststhan other scolytids

- Attack living, recently killed trees, or dead trees (high moisture content)

Dead tree in river under attack

ResearchTrap Studies

1) Used to direct scouting activities (esp. when sprays not made)

2) Used to direct timing of spray treatments

Value of Traps

Ambrosia beetles:Over-winter as adultsNo temperature dependent larval development period in springRemain inactive until conditions favorableEmerge suddenly in large numbersGenerally attack before bud breakHowever, emergence can vary widely between years and locations

Bee

tles

Cap

ture

d P

er D

ay

0

10

20

30

40

50

60

70

80

60 80 100 120 140 160 180 200

Site-1

Site-2

2007

0

1

2

3

4

60 80 100 120 140 160 180 200

Site-1

Site-2

2006

Apr May Jun JulMar

0

0.2

0.4

0.6

0.8

1

1.2

1.4

60 70 80 90 100 110 120 130 140 150 160 170 180

Site-1

Site-2

0

2

4

6

8

10

12

60 70 80 90 100 110 120 130 140 150 160 170 180

Site-1

Site-2

2007

2006

Apr May JunMar

2006 2006

2007 2007

Site 1Site 2

- Peaks at different times in different years- Within years, similar between sites and X. crass and X. germ

Xylosandruscrassiusculus

Xylosandrusgermanus

3) Extension assistanceWidely-spaced Contiguous

Procoxae

Xylosandrus Other

Identifying the Granulated (Asian) Ambrosia Beetle

1) Color – Reddish-brown to orange-brown(may appear two toned)

2) Non-shiny patch on abdomen tip(visible with 10x hand lens)

Lindgren Trap

Chestnut Trees with Gallery Cages

Trapping / Tree Attack Study (1999)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan

Tota

l Num

ber

0

25

50

75

100

500

550

600

Tree AttacksTrap Collections

Other Findings During Study- More galleries on southwest side of tree

X. germanus – 195.2 + 13.1X. crassiusculus – 238.6 + 22.0

- Females vs. Males emergingX. germanus – 16 : 1X. crassiusculus – 15 : 1

Males did emerge

- Mixed species emergence from same gallery

- Emergence occurred in spurtsX. germanus – Up to 7 events from 54 to 89 daysX. crassiusculus – Up to 4 events from 55 to 94 days

- Greater progeny production by X. crassiusculusX. germanus – 4.4 + 0.5 per galleryX. crassiusculus – 9.9 + 4.0 per gallery

Trap Features Evaluated:

Trap typeLure typeKilling agentsCostEase of use

Ambrosia Beetle Trap Comparisons (2003)

X.crass

X.germ

X.sax

Species

Traps With Greater Collections Than a Non-Baited Lindgren Trap

All baited with pill bottle ethanol lure

- Traps with highestcapture rates

- Bottle trap was best all around trap- Cheapest to make- Easiest to operate- Effective on problem ambrosia beetles

Improved- Best lure (pill bottle with wick)had highest ethanol release rate)

Trap Height Study – Bottle Trap (2006 - 2008)

3 m (9.8 ft)

1.7 m (5.6 ft)

0.5 m (1.6 ft)

TN

0 100 200 300 400 500

A

B

C

OHH

eigh

t

Average Cumulative Trap Captures (+ SE)

Xylosandrusgermanus

F = 544.64, df = 2, 14, P < 0.0001

0 5 10 15 20 25

A

B

BTN

Hei

ght (

m)


F = 21.57, df = 2, 14, P = 0.0001

0 10 20 30 40 50 60 70

A

B

BVA

Hei

ght (

m)


F = 50.48, df = 2, 46, P < 0.0001


0 10 20 30 40

A

B

AB

Hei

ght

0 20 40 60 80

A

B

A

Hei

ght

VA (2006)

VA (2007)

0 2 4 6 8 10 12 14

A

B

C

Hei

ght

TN (2006)

0 40 80 120 160

A

B

A

Hei

ght

TN (2007)

Average Cumulative Trap Captures (+ SE)Average Cumulative Trap Captures (+ SE)

Xylosandruscrassiusculus

F = 34.47, df = 2, 14, P < 0.0001

F = 21.36, df = 2, 14, P = 0.0001

F = 8.61, df = 2, 14, P = 0.004

F = 3.93, df = 2, 14, P = 0.044

Ohio Virginia Tennessee

Tota

l

0

1000

2000

3000

4000

Ohio Virginia Tennessee0

1000

2000

3000

4000

Total Captures in Three States During 2007


ResearchInducing Tree Attacks

Injecting Trees With Ethanol

After Ethanol Injection

Attacks Induced on Previously Healthy Trees (Trunk Size ~ 4 Inches)

Attacks on Adjacent Tree Shoots Attacks High in Tree


Injection Point


Beetle Attempting to Enter TreeCheckered Beetle Attacking

Ambrosia Beetle Boring Into the Tree

Ethanol-Baited Trap

Versus

Trap with Ethanol-Injected Bolt

ResearchInsecticide Studies

Insecticide / Biopesticide Sprays

Injecting Trees With Ethanol Using an Arbojet

Ambrosia Beetle Attacks Triggered

Insecticide Test – April 24 to May 22, 2009

I. Trees Treated:A. Systemic Soil Drenches Rate / 100 gallons

- Acelepryn 32 floz- Safari 24 oz

B. Systemic Trunk Sprays- Safari 8 oz- Safari + PentraBark (wetting agent) 8 oz

C. Contact Pyrethroid Trunk Sprays- Onyx Pro Insecticide 32 floz- Perm-Up 3.2 EC 160 floz - Scimitar CS 5 floz

II. Trees Injected With Ethanol(75 ml of 50% ETOH)

- 34 days after systemic drenches- 1 day after trunk sprays

III. Trees Monitored for New Attacks (~ 1 month)

IV. Attacked Trees Then Held in Lab to Rear Beetles

Apr24 Apr27 Apr30 May5 May11 May15 May220

3

6

9

12Acelepryn Drench

Total hits = 75


0

3

6

9

12Safari Drench

*Total hits = 94

Mea

n N

ew A

mbr

osia

B

eetle

Atta

cks

(+ S

EM

)

Systemic Soil Drenches


3

6

9

12Control (Ethanol Injected)

Total hits = 70

Indicates significant difference from control (P < 0.05)*

(chlorantraniliprole)

(dinotefuran)

Mea

n N

ew A

mbr

osia

B

eetle

Atta

cks

(+ S

EM

)


3

6

9


Total hits = 70

Systemic Trunk Sprays



3

6

9

12Safari Trunk Spray + Pentra Bark

Total hits = 49(dinotefuran)


3

6

9

12Safari Trunk Spray

*Total hits = 59

(dinotefuran)

Mea

n N

ew A

mbr

osia

B

eetle

Atta

cks

(+ S

EM

)


3

6

9


Total hits = 70

Contact PyrethroidTrunk Sprays



3

6

9

12Perm Up Trunk Spray

* *

Total hits = 5(permethrin)


3

6

9

12Onyx Trunk Spray

*

Total hits = 42(bifenthrin)


3

6

9

12Scimitar Trunk Spray

Total hits = 59(lambda-cyhalothrin)

Biopesticide / Insecticide Test – June 24 to July 16, 2009

I. Trees Treated:A. Contact Pyrethroid Trunk Sprays (160 ml / 100 gal)

- Perm-Up 3.2 EC - Perm-Up 3.2 EC + PentraBark

B. Biopesticides (421 ml / gallon ~ 10% )- Cinnacure (30% cinnamaldehyde)- Cinnacure + PentraBark- EcoTrol (10% rosemary oil; 2% peppermint oil)

II. Trees Injected With Ethanol(75 ml of 10% ETOH)

- 1 day after trunk sprays

III. Trees Monitored for New Attacks (~ 1 month)

IV. Attacked Trees Then Held in Lab to Rear Beetles

Most antennallyactive on X. germanus

Mea

n N

ew A

mbr

osia

Bee

tle A

ttack

s (+

SE

M)

Biopesticide Trunk Sprays


Cinnacure

Jun24 Jun25 Jun26 Jun29 Jun30 Jul1 Jul2 Jul9 Jul160

2

4

6

Total hits = 11

EcoTrol


2

4

6

Total hits = 29

Cinnacure + PentraBark


2

4

6

Total hits = 14

Control (No Injection)


2

4

6

Control (Ethanol Injected)


0

2

4

6

Total hits = 34

Total hits = 13

Pyrethroid Trunk Sprays

Control (No Injection)


2

4

6

Control (Ethanol Injected)


0

2

4

6

Total hits = 34

Total hits = 13

Permethrin


2

4

6

Total hits = 9

Permethrin + PentraBark


2

4

6

Total hits = 18

Mea

n N

ew A

mbr

osia

Bee

tle A

ttack

s (+

SE

M)

Biopesticide ambrosia beetle test - 2009Total Average Attacks

Permeth

rin

Cinn. +

Pen

tra

Cinnac

ureW

ater

Permeth

rin +

Pentra

Ethano

l Injec

ted

Ecotro

l

Mea

n +

SE

M

0

2

4

6

8

10

ResearchPlant Stress Studies

Ambrosia Beetle Tree Stress Test

Stress Treatments:1) Planting to deep2) Root drowning3) Delayed dormancy break4) Defoliation5) Drought stress

Data Collected:1) Number of new galleries

(3 times / week)2) Sticky trap catches3) Species reared from trees

Drought stress treatment

Average Attacks + Standard Error

0 4 8 12 16 20

Delay May

Drought

Delay April

Defoliation

Plant Depth

Root Drowning

Control

Average Attacks + Standard Error

0 4 8 12 16 20

Delay May

Plant Depth

Drought

Delay April

Root Drowning

Defoliation

Control

Redbud Tulip Poplar

Stress Treatments – Average Total Attacks (April 24 to May 15, 2009)

No significant differences between treatments (P < 0.05)

Thysanoes fimbricornis

Asian or Granulated Ambrosia Beetle

Average Attacks (+ SEM) Average Attacks (+ SEM)

Average Sticky Trap Captures (+ SEM)

0 20 40 60 80

Defoliation

Delay April

Plant Depth

Delay May

Root Drowning

Drought

Control

Average Attacks (+ SEM)

0 4 8 12 16 20

Delay May

Drought

Delay April

Defoliation

Plant Depth

Root Drowning

Control

Stress Treatments – Redbud Trees (Apr. 24 to May 15, 2009)

No significant differences between treatments (P < 0.05)

Tree Attacks(Thysanoes fimbricornis)

Sticky Trap Captures(all Scolytids)

ManagementPlan

Preventing Damage

Factors Increasing Attack Risk

1) Plants still dormant, but beetles being trapped

7) Planting near water sites (high humidity)

6) Time of year (March to May)

5) Fertilization terminated after July

4) Last pyrethroid spray over 4 weeks ago

3) Stressed crop (New transplant, drought, disease, freeze, poor drainage, trunk injury, etc.)

2) Susceptible species (Cherry, chestnut, dogwood, golden rain tree, lilac, maple, hydrangea, redbud,weeping mulberry, yellowwood, or others with past problems)

Ethanol release

Use Traps for Early Detection of Activity

Look for Key Indicator Species


- Thorough spray coverage

- Use effective insecticides:

Permethrin: Perm-Up 3.2 ECBiopesticides ???? (Future)

Insecticide Management

Management too lateif toothpick strands are present

Not labeled for ambrosia beetles

in walnutLabel Site: http://www.cdms.net/manuf/default.asp

Some Conclusions- 3 species problematic in Tennessee nurseries (Xcrass, Xgerm, Xsax)

- Ethanol-baited traps catch large variety of ambrosia beetles- Different species have different activity periods- Within species peak captures varies by year (value of traps)- Trapping Xcrass, Xgerm, and Xsax coincides with tree attacks- Bottle trap was cheap and effective- Low height settings are best

- Ethanol injections induce Xylosandrus attacks - Value:- Trap trees ????- Timing insecticide sprays- Facilitate insecticide studies

- Attacks were induced in summer with ethanol

- Most induced attacks occurred during first week and then declined:- Change in host suitability ?????- Drop in ethanol release ????

Some Conclusions

- Need more work to understand relationship between:- Types of plant damage and associated stress signals- Ambrosia beetle host selection factors- Host quality factors for the ambrosia fungus

Acknowledgments

USDA-ARS, Wooster, OHJames Moyseenko Alane RobinsonBetsy Anderson Abby HartGerald Hammel Leona Horst

Multiple Commercial Nurseries

FundingUSDA-ARS Floriculture and Nursery Research InitiativeUSDA-ARS Specialty Crop Block GrantHorticultural Research Institute and American Nursery & Landscape Association USDA-APHIS Middle Tennessee Nursery Association

Virginia TechCarmella Whitaker

Tennessee State UniversityNadeer YoussefJoshua BashamJoshua MedleySamuel Patton

Documents

Advances in Understanding Ambrosia Beetle Chemical Ecology