Polyphagous Shot Hole Borer+ Fusarium Dieback Field Identification Guide

Signs+ symptoms

on 31 host trees in Southern

California

ContributorsAkif EskalenUC Riverside

John KabashimaUC Cooperative Extension

Monica DimsonUC Cooperative Extension

ImagesAll images in this field guide provided by Akif Eskalen, John Kabashima, or Monica Dimson unless cited otherwise below.

p. 6(a), (b) Gevork Arakelian, LA County Dept. of Agriculture(d) Mike Lewis, UC Riverside

p. 9(a) Christoph Benisch<kerbtier.de>(d) UC IPM <ipm.ucanr.edu>

p. 10(a), (b), (e), (f ) UC IPM

p. 29Mesquite: Tim Thibault

All “Leaf ID” images provided by SelecTree (1995-2014. June 2014. <selectree.calpoly.edu>), excluding:p. 18, Castor bean: UC IPMp. 20, Red willow: Keir Morsep. 27, White alder: Keir Morsep. 28, Titoki: UCCE Orangep. 37, Camellia: UCCE Orange

FUNDING FOR THIS F IELD GUIDE PROVIDED BY

PRINTED NOV 2014

Contents

Photo: Galleries in box elder branch.

5 . . . . . . . Background6 . . . . . . . Beetle Biology and Identification7 . . . . . . . Signs and Symptoms9 . . . . . . . Look-Alike Pests11 . . . . . . Host Species

Host Species

13 . . . . . . Box elder Acer negundo14 . . . . . . Big leaf maple Acer macrophyllum15 . . . . . . Evergreen maple Acer paxii16 . . . . . . Trident maple Acer buergerianum17 . . . . . . Japanese maple Acer palmatum18 . . . . . . Castor bean Ricinus communis

19 . . . . . . California sycamore Platanus racemosa20 . . . . . . Red willow Salix laevigata21 . . . . . . Avocado Persea americana22 . . . . . . Silk tree/Mimosa Albizia julibrissin23 . . . . . . English oak Quercus robur24 . . . . . . Coast live oak Quercus agrifolia25 . . . . . . London plane Platanus x acerifolia26 . . . . . . Fremont cottonwood Populus fremontii27 . . . . . . White alder Alnus rhombifolia28 . . . . . . Titoki Alectryon excelsus

Contents

Photo: Galleries in castor bean branch.

29 . . . . . . Engelmann oak Quercus engelmannii30 . . . . . . Cork oak Quercus suber31 . . . . . . Valley oak Quercus lobata32 . . . . . . Coral tree Erythrina corallodendron33 . . . . . . Palo verde Parkinsonia aculeata34 . . . . . . Moreton Bay chestnut Castanospermum australe35 . . . . . . Mesquite Prosopis articulata36 . . . . . . Weeping willow Salix babylonica37 . . . . . . Camellia Camellia semiserrata

38 . . . . . . American sweetgum Liquidambar styraciflua39 . . . . . . Red flowering gum Eucalyptus ficifolia40 . . . . . . Chinese flame/ Goldenrain Koelreuteria bipinnata K. paniculata 41 . . . . . . Coast redwood Sequoia sempervirens42 . . . . . . Honey locust Gleditsia japonica G. triancanthos43 . . . . . . Olive Olea europaea44 . . . . . . Reporting a Suspect Tree

5

Background

The Polyphagous Shot Hole Borer (PSHB), Euwallacea sp., is an invasive beetle from southeast Asia that vectors three fungi: Fusarium euwallaceae, Graphium sp., and Acremonium sp. Adult females attack a wide variety of host species, tunneling galleries in which to lay their eggs and grow the fungi. Both adults and larvae feed on this fungus, which spreads from the galleries to attack the tree’s vascular tissue. This causes a disease called Fusarium Dieback (FD), which has been found to interrupt the transport of water and nutrients in over 130 tree species.

Beetle/Fungal ComplexPolyphagous Shot Hole Borer (a: immature female) + Fusarium euwallaceae, Graphium sp., and Acremonium sp. (b: in Avocado)

a b

Beetle Biology and ID

6

(c) Relative size of male and female. (d) Life stages from larva to adult (female). Most of the beetle’s life cycle is spent in the galleries.

Adult females (a) are black in color and 1.8-2.5 mm long.Adult males (b) are brown and smaller than females at 1.5 mm long. More females are produced than males, which are flightless and very rarely leave the galleries. Mature siblings mate with each other so that females are already pregnant when they leave to start their own galleries.

a b

c d

Signs and Symptoms

7

Entry/exit holes (e): ~0.85 mm (0.033 in) in diameter. Abdomen of female may be seen protruding from the hole. Photo to scale.

External Symptoms

Attack symptoms, a host tree’s visible response to stress, vary among species. Gumming (a), staining (b), sugary exudates (c), and/or frass (d) may be noticeable before the beetle itself.

a b

c d

e

Signs and Symptoms

8

Internal Symptoms

Fusarium euwallaceae causes brown to black discoloration in infected wood. Scrape away bark around the entry/exit hole to reveal dark staining surrounding the gallery (a, b). Cross-sections of cut branches (c) show the extent of infection.

Discoloration caused by Fusarium euwallaceae

Dieback

Advanced F. euwallaceae infections will eventually lead to branch dieback, as seen on this Engelmann oak (circled in yellow).

a b c

9

Look-Alike PestsLook out for damage caused by other wood-boring beetles and/or fungi that can be mistaken for signs and symptoms of PSHB/FD.

Secondary ambrosia beetle, Xyleborus saxeseniHosts: Stressed and dying treesLook for: beetles 2-2.4 mm long (a); smaller entry holes than those of PSHB (b); reddish frass and/or sap; wet discoloration and/or dead tissue around entry hole and beneath bark (c)

Western sycamore borer, Synanthedon resplendensHosts: Species of sycamore, oak, and ceanothusLook for: larvae 25-38 mm long (d); roughened bark (e); reddish sawdust-like frass and/or pupal cases (f ) in bark crevices or on

ground; bleeding

b

a

c

e fd

10

Look-Alike Pests

Oak ambrosia beetles, Monarthrum dentiger, M. scutellare (e)Hosts: Oak species, tanoak, CA buckeyeLook for: slightly larger beetles (M. scutellare: 3.5-4.1 mm long, M. dentiger: 1.9-2.4 mm) and entry-holes (1-1.5 mm diameter) with bleeding, frothing, bubbling, or white boring dust (f ) that is tan when oxidized; often attack stressed trees

Foamy bark canker, Geosmithia pallida + Western oak bark beetle, Pseudopityophthorus pubipennisHosts: Coast live oakLook for: beetles 1.7-2.3 mm long (a); reddish frass (b), reddish sap, wet discoloration, and/or foamy liquid (c) from smaller entry-hole than that of PSHB; dead tissue around entry hole, beneath bark (d)

a

b

c d

e f

11

Host Species

• Acacia (Acacia spp.)• American sweetgum

(Liquidambar styraciflua) • Avocado (Persea americana)• Big leaf maple

(Acer macrophyllum)• Blue palo verde

(Cercidium floridum) • Box elder (Acer negundo) • Brea (Cercidium sonorae)• California sycamore

(Platanus racemosa)• Camellia

(Camellia semiserrata)• Castor bean

(Ricinus communis)• Chinese holly (Ilex cornuta) • Coast live oak

(Quercus agrifolia)• Coral tree

(Erythrina corallodendron)• Cork oak (Quercus suber)

• Engelmann oak (Quercus engelmannii)

• English oak (Quercus robur)• Evergreen maple (Acer paxii)• Fremont cottonwood

(Populus fremontii)• Goodding’s black willow

(Salix gooddingii)• Japanese maple

(Acer palmatum)• Japanese wisteria

(Wisteria floribunda)• London plane

(Platanus x acerifolia)• Mesquite (Prosopis articulata)• Mimosa (Albizia julibrissin)• Moreton Bay chestnut

(Castanospermum australe)• Palo verde

(Parkinsonia aculeata)• Red flowering gum

(Eucalyptus ficifolia)

Reproductive HostsTree species suitable for reproduction of next generation of beetles + growth and development of symbiotic fungi. These species include (view most current list at eskalenlab.ucr.edu):

continued on page 12

12

Host Species

• Brazilian pepper (Schinus terebinthifolius)

• California bay laurel (Umbellularia californica)

• Camphor (Cinnamomum camphora)

• Chinese flame tree, Goldenrain (Koelreuteria spp.)

• Chinese plum (Prunus mume)

• Coast redwood (Sequoia sempervirens)

• Elm species (Ulmus spp.)

• Honey locust (Gleditsia spp.)• Japanese cherry

(Prunus serrulata)• Olive (Olea europaea)• Orange (Citrus sinensis)• Moreton Bay fig

(Ficus macrophylla)• Peach (Prunus persica)• Persimmon (Diospyrus kaki)• Shamel ash (Fraxinus uhdei)• Silk floss (Ceiba speciosa)• Silver birch (Betula pendula)• Victorian box

(Pittosporum undulatum)

Fusarium Dieback Susceptible HostsPSHB has been observed attacking over 300 tree species. At least 138 of those species are susceptible to Fusarium Dieback. PSHB is not known to reproduce in these species, but it can cultivate fungi in and stress the infected tree. These include:

• Red willow (Salix laevigata)• Titoki (Alectryon excelsus)• Tree of heaven

(Ailanthus altissima)• Trident maple

(Acer buergerianum)

• Valley oak (Quercus lobata)• Weeping willow

(Salix babylonica)• White alder

(Alnus rhombifolia)

Reproductive Hosts, cont.

13

Box Elder

Acer negundoNative reproductive host LEAF ID

SymptomsStaining, bleeding, frass

14

Big Leaf Maple

Acer macrophyllumNative reproductive host

LEAF ID

SymptomsStaining

15

Evergreen Maple

Acer paxiiReproductive host LEAF ID

SymptomsStaining

16

Trident Maple

Acer buergerianumReproductive host

LEAF ID

SymptomsStaining

17

Japanese Maple

Acer palmatumReproductive host LEAF ID

SymptomsStaining

18

Castor Bean

Ricinus communisInvasive reproductive host

LEAF ID

SymptomsStaining

19

California Sycamore

Platanus racemosaNative reproductive host LEAF ID

SymptomsStaining

20

Red Willow

Salix laevigataNative reproductive host

LEAF ID

SymptomsStaining, frass

21

Avocado

Persea americana Reproductive host LEAF ID

SymptomsSugary exudate, staining

22

Silk Tree/Mimosa

Albizia julibrissinReproductive host

LEAF ID

SymptomsStaining, gumming

23

English Oak

Quercus roburReproductive host LEAF ID

SymptomsStaining

24

Coast Live Oak

Quercus agrifoliaNative reproductive host

LEAF ID

SymptomsStaining

25

London Plane

Platanus x acerifoliaReproductive host LEAF ID

SymptomsStaining

26

Fremont Cottonwood

Populus fremontiiNative reproductive host

LEAF ID

SymptomsStaining

27

White Alder

Alnus rhombifoliaNative reproductive host LEAF ID

SymptomsStaining

28

Titoki

Alectryon excelsusReproductive host

LEAF ID

SymptomsGumming, staining

29

Engelmann Oak

Quercus engelmanniiNative reproductive host LEAF ID

SymptomsStaining

30

Cork Oak

Quercus suberReproductive host

LEAF ID

SymptomsStaining

31

Valley Oak

Quercus lobataNative reproductive host LEAF ID

SymptomsStaining

32

Coral Tree

Erythrina corallodendronReproductive host

LEAF ID

SymptomsStaining

33

Palo Verde

Parkinsonia aculeataReproductive host LEAF ID

SymptomsStaining, frass

34

Moreton Bay Chestnut

Castanospermum australeReproductive host

LEAF ID

SymptomsStaining, gumming

35

Mesquite

Prosopis articulataNative reproductive host LEAF ID

SymptomsStaining

36

Weeping Willow

Salix babylonicaReproductive host

LEAF ID

SymptomsStaining, gumming, frass

37

Camellia

Camellia semiserrataReproductive host LEAF ID

SymptomsStaining

38

American Sweetgum

Liquidambar styracifluaReproductive host

LEAF ID

SymptomsStaining

39

Red Flowering Gum

Eucalyptus ficifoliaReproductive host LEAF ID

SymptomsStaining

40

Chinese Flame/Goldenrain

Olea europaeaFD-susceptible host

LEAF ID

SymptomsGumming, staining

Koelreuteria bipinnata,K. paniculata

FD-susceptible hostsLEAF ID (K. BIPINNATA)

41

Coast Redwood

Sequoia sempervirensNative FD-susceptible host LEAF ID

SymptomsEntry/exit hole only

42

Honey Locust

Gleditsia triancanthos, G. japonica

FD-susceptible hostLEAF ID (G. TRIANCANTHOS)

SymptomsStaining

43

Olive

Olea europaeaFD-susceptible host LEAF ID

SymptomsGumming, staining

44

Reporting a Suspect Tree

1

2

PSHB/FD has been detected in Los Angeles, Orange, Riverside, San Bernardino, and San Diego Counties*.

Please report suspected tree infestations in California to the Eskalen Lab at UC Riverside at:

eskalenlab@gmail.com

Infestations in Orange County can be reported to the local UC Cooperative Extension office at:

pshb.ucce.oc@gmail.com

Submit the following information:

• Your contact information (name, city, phone number and/or email depending on method of submission)

• Suspect tree species• Description of suspect tree’s location (and/or GPS

coordinates)• Description of suspect tree’s symptoms• Photos of suspect tree and close-up photos of

symptoms (see examples on page 45)

Based on the symptom description and photos, UCCE Orange County or UC Riverside will decide whether a field assessment is needed to confirm the infestation.

A suspect tree reporting form can be downloaded at eskalenlab.ucr.edu/handouts/suspecttreereport.pdf.

*as of November 2014

45

Reporting a Suspect Tree

1 2

3

Take photos of suspect trees from several distances. Include photos of:

1. the trunk or symptomatic branches

2. the symptoms (close-up)

3. the entry/exit hole, if visible, with a ballpoint pen for scale (remove gumming or exudate if necessary)

If dieback is observed, include a picture of the entire tree.

Photos: Coast live oak, Quercus agrifolia

Stay up-to-date on the latest PSHB research atEskalen Lab (http://eskalenlab.ucr.edu) or the UC Riverside

Center for Invasive Species Research (http://cisr.ucr.edu).

It is the policy of the University of California (UC) and the UC Division of Agriculture & Natural Resources not to engage in discrimination against or harassment of any person in any of its programs or activities on the basis of race, color, national origin, religion, sex, gender, gender expression, gender identity, pregnancy (which includes pregnancy, childbirth, and medical conditions related to pregnancy or childbirth), physical or mental disability, medical condition (cancer-related or genetic characteristics), genetic informa-tion (including family medical history), ancestry, marital status, age, sexual orientation, citizenship, or service in the uniformed services (as defined by the Uniformed Services Employment and Reemployment Rights Act of 1994 [USERRA]), as well as state military and naval service. This policy is intended to be consistent with the provisions of applicable state and federal laws and University policies.University policy also prohibits retaliation against any employee or person in any of its programs or activities for bringing a complaint of discrimination or harassment pursuant to this policy. This policy also prohibits retaliation against a person who assists someone with a complaint of discrimination or harassment, or participates in any manner in an investigation or resolution of a complaint of discrimination or harassment. Retaliation includes threats, intimidation, reprisals, and/or adverse actions related to employment or to any of its programs or activities.In addition, it is the policy of the University and ANR to undertake affirmative action, consistent with its obligations as a Federal contractor, for minorities and women, for persons with disabilities, and for covered veterans. The University commits itself to apply every good faith effort to achieve prompt and full utilization of minorities and women in all segments of its workforce where deficiencies exist. These efforts conform to all current legal and regulatory requirements, and are consistent with University standards of quality and excellence.In conformance with Federal regulations, written affirmative action plans shall be prepared and maintained by each campus of the University, including the Division of Agriculture and Natural Resources. Such plans shall be reviewed and approved by the Office of the President and the Office of the General Counsel before they are officially promulgated.Inquiries regarding the University’s nondiscrimination policies may be directed to Linda Marie Manton, Affirmative Action Contact, University of California, Agriculture and Natural Resources, 2801 Second Street, Davis, CA 95618, (530) 750-1318.