UC Master Gardeners, Santa Clara County, CA
University of California
UC Master Gardeners, Santa Clara County, CA

Oak Root Fungus Resistant Varieties

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Plants Resistant or Susceptible to Armillaria mellea,
The Oak Root Fungus

Robert D. Raabe
Department of Environmental Science and Management
University of California, Berkeley

Introduction
Part A: Tested plants
   Resistant
   Moderately resistant
   Susceptible
   Resistant fruits and nuts
   Moderately resistant fruits and nuts
   Susceptible fruits and nuts
Part B: Not Tested
   Resistant
   Moderately resistant
   Susceptible

 

Armillaria mellea is a common disease producing fungus found in much of California. It commonly occurs naturally in roots of oaks but does not damage them unless they are weakened by other factors. When oaks are cut down, the fungus moves through the dead wood more rapidly than through living wood and can exist in old roots for many years. It also does this in roots of other infected trees. Infection takes place by roots of susceptible plants coming in contact with roots in which the fungus is active. Some plants are naturally susceptible to being invaded by the fungus. Many plants are resistant to the fungus and though the fungus may infect them, little damage occurs. Such plants, however, if they are weakened in any way may become susceptible and the fungus may kill them.

The plants listed here are divided into three groups. Those listed as resistant are rarely damaged by the fungus. Those listed as moderately resistant frequently become infected but rarely are killed by the fungus. Those listed as susceptible are severely infected and usually are killed by the fungus.

The fungus is variable in its ability to infect plants and to damage them. Thus in some areas where the fungus occurs, more plant species may be killed than in areas where other strains of the fungus occur.

The list is composed of two parts. In Part A, the plants were tested in two ways. Most were grown in an old orchard area known to be infested by the fungus at the University of California Deciduous Fruit Station in Santa Clara, California . Information about early procedures is not available. However, all plants tested since 1952 were planted in the infested soil. In addition, two six to eight inch pieces of woody branch material colonized by the fungus in the laboratory were put next to the root system at the time of planting. Isolates used in these pieces were selected for their ability to be highly virulent forms. Ten plants of each species were tested. Following planting, plants were monitored periodically and dead plants, particularly those with the oak root fungus were recorded. After ten years, all remaining plants were pulled and their root systems were rated as to the amount of infection found. In addition, some plants were tested in greenhouse experiments in which ten plants each were exposed up to one year to two strains of the fungus as listed above except this was done in unglazed ceramic pots. This project was supported by a grant from the Elvin J Slosson Fund and plants so tested are marked with a double asterisk**.

In the Fruits and Nuts section, many plants are included even though they may not be used in the production of crops. They are included here so that researchers may want to include them in their breeding experiments. If any of these plants have been known to be used as ornamental plants, they are included in that section.

Although when tested, pears have been found to be resistant, recently pears in Lake County are becoming infected. Research will determine the reasons for this. Also, the fungus in this area grows through the soil and can spread this way. This is the only known area where this occurs.

Plants listed with a double asterisk** were tested in pots in a research greenhouse. This research was funded by a grant from the Elvenia Slosson Fund.

Plants listed in Part B were not tested for resistance or susceptibility. Information presented is based on finding plants infected by the fungus, or finding plants that are not infected. Additional information was obtained from the California Plant Disease Host Index, published by the California Department of Food and Agriculture and the list of plant diseases published by the American Phytopathological Society, Fungi on Plants and Plant Products in the United States. Plants marked with an asterisk * are from information supplied by the staff of Quarryhill Botanical Garden, Glen Ellen.

 

PART A: TESTED PLANTS

TESTED: RESISTANT PLANTS (back to top)

Abies concolor Colorado or White Fir
Acacia longifolia Sydney Golden Wattle, Bush Acacia
Acacia mearnsii Black Wattle
Acacia verticillata Whorl-leaved or Star Acacia
Acer cappadoicum Caucasian Maple
Acer crataegifolium Hawthorne Maple
Acer macrophyllum Big-leaf Maple, Oregon Maple
Acer palmatum Japanese Maple
Acer saccharum Sugar Maple
Acer tataricum Tartarian Maple
Acer tataricum ssp Ginnala Ginnala Maple, Amur Maple
Ailanthus altissima Tree-of-heaven
Ailanthus giraldii  
Angophora cordifolia Gum Myrtle, Smooth Bark Apple
Arbutus menziesii Madrone
Asimina triloba Papaw, Pawpaw
Berberis polyantha  
Betula pumila Swamp Birch, American Dwarf Birch
Brachychiton pupulneus Kurrajong Bottle Tree
Broussonetia papyrifera Paper Mulberry
Brugmansia suaveolens Angel’s Trumpet
Buxus sempervirens Common or English Box
Buxus sempervirens var. arborescens Common Box (Tree Form)
Callicarpa japonica Beauty-berry
Calocedrus decurrens Incense Cedar
Calycanthus occidentalis Western Spice Bush, CA Allspice
Carpenteria californica Bush or Tree Anemone
Catalpa bignonioides Common Catalpa, Indian Bean
Catalpa hybrida Hybrid Catalpa
Catalpa ovata Chinese Catalpa
Celtis australis European or Mediterranean Hackberry
Celtis occidentalis Hackberry
Ceratonia siliqua Carob, St John’s Bread, Algarroba
Cercis occidentalis CA Redbud, Western Redbud
Cercis siliquastrum Judas Tree, Love Tree
Chaenomeles cathayensis Flowering Quince
Chaenomeles japonica Japanese Flowering Quince
Chamaecyparis lawsoniana “Ellwoodii” Ellwood Cypress
Chamaerops humilis Fan Palm
Chionanthus retusa Chinese Fringe Tree
Clerodendron bungei Kashmir Bouquet, Glory Flower
Cornus mas Cornelian Cherry, Sorbet
Corynabutilon vitifolium Flowering Maple
Correa “Victory Bells”  
Cotinus coggygria Smoke Tree
Cryptomeria japonica Japanese Cryptomeria or Cedar
Cupaniopsis anacardioides Carrotwood, Tuckeroo
Cupressocyparis X leylandii Leyland Cypress
Cupressus arizonica var. glabra Smooth Arizona Cypress
Diospyros glaucifolia  
Elaeagnus angustifolia Oleaster, Russian Olive, Silver Berry
Erica arborea Tree Heath
Eucalyptus camaldulensis River Red Gum
Eucalyptus cinerea Dollar-leaf Eucalyptus, Mealy Stringbark
Eucalyptus grandis Rose Gum
Eucalptus mannifera ssp Maculosa Brittle Gum
Eucalyptus melliodora Yellow Box
Eucalyptus risdonii Risdon Peppermint
Eucomia ulmoides Gutta-percha Tree
Euonymus europeus Common Spindle Tree
Exochorda korolkowii  
Exochorda racemosa Pearlbush
Fabiana imbricate Fabiana
Fraxinus angustifolia  
Fraxinus ornus Flowering Ash, Manna Ash
Fraxinus uhdei Shamel Ash, Evergreen Ash
Fraxinus velutina var. glabra “Modesto” Modesto Ash
Garrya elliptica Silk Tassel
Geijera parviflora Australian Willow, Wilga
Ginkgo biloba Maidenhair Tree
Gleditsia tricanthos inermis “Shademaster” Shademaster Locust
Grewia biloba  
Gymnocladus dioica Kentucky Coffee Tree
Hibiscus syriacus Rose-of-Sharon, Shrub Althea
Hypericum patulum St. Johnswort
Ilex aquifolium English Holly, Common Holly
Ilex x aquipernyi  
Ilex cassine Dahoon
Ilex cornuta Chinese Holly, Horned Holly
Ilex opaca American Holly
Ilex verticillata Black Alder, Winterberry
Jacaranda mimosifolia Jacaranda
Koelreuteria paniculata Golden Rain Tree, Pride of India
Lagerstroemia x amabilis Crepe Myrtle
Ligustrum quinhoui  
Ligustrum tschonskii  
Liquidambar orientalis Oriental Sweet Gum
Liquidambar styraciflua American Sweet Gum, Liquidambar
Liriodendron tulipifera Tulip Tree, Yellow or Tulip Poplar
Lonicera nitida Box Honeysuckle
Lyonia mariana Stagger Bush
Maackia amurense  
Maclura pomifera Osage Orange
Magnolia grandiflora Southern Magnolia
Magnolia salicifolia Anise magnolia, Willow-leaf Magnolia
Mahonia aquifolium Holly Mahonia, Oregon Grape
Mahonia nevinii Nevin Mahonia
Malus florentina  
Malus floribunda Japanese Flowering Crab
Malus ioensis Prairie Crabapple
Maytenus boaria Mayten Tree
Melaleuca stypheliodes Prickly Paperbark
Melia azedarach Persian lilac, Bead Tree
Metasequoia glyptostroboides Dawn Redwood
Myrica pensylvanica Bayberry, Candleberry
Nandina domestica Sacred Bamboo, Heavenly Bamboo
Paulownia fortunei  
Persea indica Indian Avocado
Phellodendron amurense Amur Cork Tree
Phellodendron chinense Chinese Cork Tree
Philadelphus coronaries Mock Orange
Phlomis fruticosa Jerusalem Sage
Photinia davidsoniae  
Photinia x fraseri  
Pinus canariensis Canary Island Pine
Pinus halepensis Aleppo Pine
Pinus monticola Western White Pine
Pinus nigra ssp. Larico Corsican Pine
Pinus patula Mexican pine, Jelecote Pine
Pinus radiate Monterey Pine
Pinus sylvestris Scots Pine, Scotch Pine
Pinus torreyana Torrey Pine
Pistacia chinensis Chinese Pistache, Chinese Pistachio
Pittosporum crassifolium Caro, Karo, Evergreen Pittosporum
Pittosporum eugenoides Terata, Lemonwood
Pittosporum heterophyllum  
Pittosporum phillyreoides Narrow-leaved or Weeping Pittosporum
Pittosporum rhombifolium Queensland Pittosporum
Pittosporum tenuifolium Tawhiwhi
Pittosporum undulatum Victorian Box, Orange Berry Pittosporum
Pittosporum viridiflorum Cape Pittosporum
Prunus caroliniana American Cherry Laurel
Prunus ilicifolia Holly-leaf Cherry, California Cherry
Prunus lyonii Catalina Cherry
Prunus virginiana Choke Cherry
Pseudocydonia sinensis Chinese Quince
Psidium littorale var. longipes Strawberry or Purple Strawberry Guava
Quercus ilex Holly Oak, Holm Oak, Truffle Oak
Quercus lobata Valley Oak, California White Oak
Quercus phillyraeoides  
Quillaja saponaria Soapbark Tree, Quillay, Soap Bush
Rhus aromatica Fragrant Sumac, Lemon Sumac
Rhus copallina Shining Sumac, Dwarf Sumac
Sambucus canadensis American or Sweet Elder
Sapium sebiferum Chinese or Vegetable Tallow Tree
Sequoia sempervirens Coast Redwood, CA Redwood
Shepherdia argentea Buffalo Berry, Silverberry
Sophora japonica Japanese Pagoda Tree
Styrax japonicum Japanese Snowball
Symphoricarpos sp. Snowberry
Syngonium paniculatum Australian Bush Cherry
Taxodium distichum Bald Cypress, Swamp Cypress
Ternstroemia sylvatica Mexican Ternstroemia
Tilia tomentosa Silver Linden, Silver Lime
Tristania conferta Brisbane Box
Ulmus x “Sapporo Gold”  
Ulmus parvifolia Chinese Elm
Vitex agnus-castus Blue Chaste Tree, Chaste Tree
Wisteria sinensis  

TESTED: MODERATELY RESISTANT PLANTS (back to top)

Abelia grandiflora Glossy Abelia, White Abelia
Abutilon pictum Flowering Maple
Acer negundo ssp. Californicum Box Elder
Acer tegmentosum  
Albizia julibrissin Silk Tree
Amorpha fruticosa False Indigo, Indigo Bush
Amorpha fruticosa var. nana Bastard Indigo
Berberis darwinii Darwin Barberry
Berberis thunbergii Japanese Barberry
Berberis wilsoniae Wilson Barberry
Cephalanthus occidentalis Buttonbush, Buttonwillow, Honey Bells
Cestrum elegans  
Chamaecyparis lawsoniana Lawson Cypress, Port Orford Cedar
Chamaecytisus purpureus Purple Broom
Chimonanthus praecox Wintersweet
Cladrastis lutea Kentucky or American Yellowood
Crataegus phaenopyrum Washington Thorn
Crotalaria agatiflora  
Dais cotinifolia Canary-Bird Bush, Pompon Tree
Elaegnus commutate Silverberry
Eucalyptus polyanthemos Redbox Gum, Silver Dollar Gum
Eucalyptus pulchella White Peppermint
Euonymus japonica Evergreen or Japanese Euonymus
Grevillea robusta Silk Oak
Grewia similes  
Hebe x andersonii Anderson Speedwell
Hebe speciosa Showy or Imperial Speedwell
Hovenia dulcis Japanese or Chinese Raisin Tree
Iochroma cyanea Purple Tobacco
Koelreuteria paniculata Golden Rain Tree, Pride of India
Lagerstroemia indica Crape Myrtle
Ligustrum japonicum Japanese Privet, Wax-leaf Privet
Myrtus communis Myrtle
Nerium oleander Oleander
Paulownia fargesii  
Photinia bearverdiana  
Picea abies Norway Spruce
Pinus brutea ssp. Eldarica Eldarica Pine
Pinus jeffreyi Jeffrey Pine
Pinus nigra Austrian Pine
Pittosporum tobira Japanese Pittosporum, Tobira
Prunus grayana Japanese Bird Cherry
Prunus subhirtella Rosebud Cherry, Spring Cherry
Pseudotsuga menziesii Douglas Fir
Pyracantha coccinea Scarlet Firethorn
Pyracantha coccinea ‘Lalandei” Lalande Pyracantha
Pyracantha coccinea “Wyattii”  
Pyracantha crenatoserrata  
Pyracantha crenulata var. kansuensis Kansu Firethorn
Pyracantha x “Forest Hills”  
Pyracantha x “Morettii”  
Quercus chrysolepis Canyon Oak, Golden Cup Oak
Rosmarinus officinalis Rosemary
Sequoiadendron giganteum Giant Redwood
Spiraea prunifolia Bridal Wreath, Shoe-button Spiraea
Wisteria macrostachys Wisteria
Zelkova serrata Japanese Zelkova

TESTED: SUSCEPTIBLE (back to top)

Abutilon  
Abutilon megapotamicum  
Abutilon vitifolium Trailing Abutilon
Acacia floribunda Sydney Acacia, Sydney Wattle
Acer capillipes  
Acer cauditifolium  
Acer fulvescens var. pentalobatum  
Albizzia lophantha Plum Albizz
Arbutus unedo Strawberry Tree
Azara microphylla Box Leaf Azara
Betula pendula European White Birch, Silver Birch
Buddleja davidii var. magnifica Butterfly Bush, Summer Lilac
Buddleja forestii Oxeye Butterfly Bush
Buddleja globosa Orange Ball Tree
Caesalpinia gilliesii Bird of Paradise Bush
Callistemon viminalis Weeping Bottle Brush
Carpinus betulus European Hornbeam, Common Hornbeam
Caryopteris x clandonensis Blue Mist, Bluebeard
Casuarina verticillata She Oak, Beefwood, Horsetail Tree
Ceanothus arboreus Catalina Mountain Lilac
Ceanothus thyrsiflorus Blue Blossom, Blue Brush
Cercidiphyllum japonicum  
Cotoneaster harrovianus Harrow Cotoneaster
Cotoneaster horizontalis Rock Cotoneaster
Cotoneaster lacteus Clusterberry or Parney Cotoneaster
Cotoneaster microphyllus Rockspray Cotoneaster
Cotoneaster pannosus Silver Leaf Cotoneaster
Cotoneaster salicifolius var. floccosus Hardy Willowleaf Cotoneaster
Deutzia scabra Fuzzy Deutzia
Dodonea viscosa Native Hops
Erica carnea Winter Heath, Mediterranean Heather
Erica intertesta  
Erythrina crista-galli Cockspur Coral Tree, Coral Tree
Escallonia bifida White Escallonia
Escallonia x franciscana Rose or Slippery-elm Escallonia
Escallonia pulverulenta  
Escallonia rubra var. macrantha Red Escallonia
Eucalptus baueriana Blue Box
Eucalyptus citriodora Lemon-scented Gum
Eucalyptus gracilis Yorrell, White Mallee
Eucalyptus grossa Coarse-flowered Mallee
Eucalyptus maculata Spotted Gum
Eucalyptus pauciflora Cabbage Gum, Snow or Ghost Gum
Eucalyptus pulverulenta Silver Dollar Tree, Silver-leaved Gum
Eucalyptus rudis Desert Gum, Moitch Eucalyptus
Eucalyptus sideroxylon Pink Iron Bark, Red Iron Bark
Eucalyptus tereticormis Forest Red Gum
Euonymus japonicus “Aureo-marginata” Golden Euonymus
Euphorbia pulcherrima Poinsettia, Christmas Flower
Fagus sylvatica European Beech, Common Beech
Felecia fruticosa  
Fontanesia phillyreoides ssp. fortunei  
Fraxinus holotricha Kimberly Blue Ash
Fremontodendron mexicanum Southern or Mexican Fremontia
Genista x spachiana Eastern Broom
Gordonia lasianthus Loblolly Bay
Hakea laurina Sea Urchin Tree, Pincushion Hakea
Hakea oleifolia  
Hebe odora Boxleaf Veronica
Heteromeles arbutifolia Toyon, Christmas Berry
Hydrangea quercifolia Oakleaf Hydrangea
Hypericum beanii Henry St. Johnswort, Goldflower
Hypericum prolificum Shrubby St. Johnswort, Broombrush
Kennedia sp. Coral Tree
Kerria japonica Japanese Rose Kerria, Globe Flower
Laburnum angyroides Golden Chain Tree
Laburnum x watereri “Vossii” Long Cluster Golden Chain Tree
Leptospermum laevigatus Australian Tea Tree
Leptospermum scoparium New Zealand Tea Tree, Manuka
Ligustrum vulgare “Aureum” Yellowleaf European Privet
Lithocarpus densiflorus Tan Bark Oak
Malus x eleya Eley Crab Apple
Malus floribunda Japanese Flowering Crabapple
Malus hupehensis Tea Crab Apple
Malus sargentii Sargent Crab Apple
Malus toringoides Cutleaf Crab Apple
Melaleuca decora  
Melaleuca hypericifolia Dotted Melaleuca
Melaleuca leucadendra Cajeput Tree, Punk Tree
Melaleuca linarifolia Flax-leaf Paperbark
Melaleuca radula  
Melaleuca styphelioides Prickly Paperbark
Myrtus communis “Variegata” Variegated Myrtle
Paulowina tomentosa Royal Paulownia, Empress Tree
Paulownia tomentosa “Lilacina”  
Picea pungens Colorado Blue Spruce
Pinus brutia Brutia Pine
Pinus monophylla One-needled Pinyon Pine
Pinus nigra Black Pine, Austrian Pine
Prunus laurocerasus Cherry Laurel, English Laurel
Prunus triloba Flowering Almond
Pyracantha angustifolia Narrowleaf Firethorn
Pyracantha crenato-serrata Yunan Firethorn
Pyracantha crenulata Nepal Firethorn, Nepalese White Thorn
Pyracantha koidzumii Formosa Firethorn
Pyracantha rogersiana Rogers Firethorn
Quercus dumosa CA Scrub Oak
Quercus virginiana Southern Live Oak
Rhododendron cv Blue Diamond Blue Diamond Azalea
Rhus ovata Sugarbush, Sugar Sumac
Rhus trilobata Squawbush, Skunkbush
Schinus chichita var. rhoifolius Aroeira Blanca
Schinus lentiscifolius Coroba
Schinus longifolius Molle
Schinus polygamus Pepper Tree
Schinus terebinthifolius Brazilian Pepper Tree
Senna multiglandulosa Senna, Wooly Senna
Sesbania punicea Glory Pea, Scarlet Wisteria Tree
Severina buxifolia Chinese Box Orange
Sutherlandia frutescens Balloon Pea, Duck Plant
Syringa vulgaris Lilac
Tecoma stans Yellow Bells, Yellow Elder
Thuja plicata Giant Arborvitae, Western Red Cedar
Ulex europaeus Furze, Irish or Common Gorze
Viburnum tinus Laurustinus
Weigela florida Weigela
Wistaria frutescens American Wisteria
Xylosma congestum  

TESTED: RESISTANT FRUITS AND NUTS (back to top)

Carya illinoinensis Pecan
Castanea dentata American Chestnut
Castanea sativa Spanish Chestnut
Diospyros kaki Japanese Persimmon
Diospyros lotus Date-plum Persimmon
Diospyros virginiana American Persimmon, Possum Wood
Ficus carica “Kadota” Kadota Fig
Ficus carica “Mission” Mission Fig
Juglans hindsii California Black Walnut
Malus bacatta var. mandshurica Siberian Crab
Malus coronaria  
Malus glaucescens  
Malus orientalis Paradise Apple
Malus pumila  
Malus rockii  
Malus sylvestris French Crab Apple
Persea americana Avocado
Pistacia integerrima  
Prunus cerasifera Myrobalan Plum 29-C71
Prunus cerasifera Mariana Plum 2624
Prunus x domestica ssp. institia St. Julien Plum
Prunus grayana Japanese Bird Cherry
Prunus humilis Humble Bush Cherry
Prunus persica “Indian Peach” Indian Peach
Prunus pubigera  
Prunus salicina  
Prunis salicina “Methley” Methley Plum
Prunus salicifolia Black Cherry, Mexican Bird Cherry
Prunus tenella Dwarf Russian Almond
Prunus virginiana Choke Cherry
Pyrus betulifolia Birchleaf Pear
Pyrus calleryana Callery Pear
Pyrus communis French Pear, Common Pear
Pyrus communis “Bartlett” Bartlett Pear (rooted cuttings)
Pyrus communis Hybrid Old Home x Farmingdale
Pyrus elaeagrifolia  
Pyrus regelii  
Pyrus tadschikistarica  
Rubus ulmifolia inermis Mertens Thornless Blackberry
Rubus ursinus “Loganobaccus” Loganberry
Rubus ursinus “Ollalie” Ollalieberry

TESTED: MODERATELY RESISTANT FRUITS AND NUTS (back to top)

Cydonia oblonga Quince
Malus prunifolia Pear-leaf Crabapple
Prunus sp. Black Damask Plum
Prunus avium Mazzard Sweet Cherry
Prunus mexicana Big Tree Plum
Prunus mume Japanese Apricot
Prunus salicina Japanese Plum
Pyrus communis Cultivar Old Home (rooted cuttings)
Pyrus communis Winter Nelis

Additions to list (from Bob’s handwritten notes) that I did not find on the Slosson 3rd year report:

Susceptible
   Persicaria microphylla “Red Dragon”
   Salvia leucantha
   Salvia conferlifolia

Resistant
   Pandorea jasminoides

TESTED: SUSCEPTIBLE FRUITS AND NUTS (back to top)

Actinidia deliciosa Kiwi
Castanea mollissima Chinese Chestnut
Malus orthocarpa  
Malus pallinsiana  
Malus prunifolia Plum-leafed or Chinese Apple
Pistacia atlantica Mt. Atlas Mastic Tree
Pistacia mutica  
Pistacia vera Pistachio
Prunus alleghaniensis Alleghany Plum
Prunus armeniaca Apricot
Prunus armeniaca var. sibirica Siberian Apricot
Prunus bucharica  
Prunus cerasifera var. divaricata Red-leaved Cherry Plum
Prunus cerasoides  
Prunus curdica  
Prunus x dasycarpa Purple or Black Apricot
Prunus davidiana David’s Peach
Prunus domestica “Clyman” Clyman Plum
Prunus domestica “Diamond” Diamond Plum
Prunus domestica “French Prune” French Prune
Prunus dulcis  
Prunus fenzliana  
Prunus fenzliana x Prunus Americana  
Prunus gracilis Oklahoma Plum Prairie Cherry
Prunus hortulana Hortulana Plum
Prunus kansuensis Kansu Plum
Prunus mahaleb Perfumed Cherry, St. Lucien Cherry
Prunus munsoniana Wild Goose Plum
Prunus nigra Canadian Plum
Prunus pedunculata  
Prunus petunnikowii  
Prunus persica Peach
Prunus serrulata Japanese or Oriental Flowering Cherry
Prunus spinosa Sloe, Blackthorn
Prunus tomentosa Downy, Nanking, Manchu or Bush Cherry
Prunus virginiana var. demissa Chokecherry, Western Chokecherry
Pterpcarya stenoptera Chinese Wingnut
Vitis sp. Grape

 

PART B: PLANTS NOT TESTED

NOT TESTED: RESISTANT (back to top)

Acer sp. (except A. negundo var. californica  
A. capillipes, A. cauditifolium  
Aesculus x carnea  
Agonis sp. Willow Myrtle
Arctostaphylos sp. Manzanita
Araucaria sp. (except A. cunninghamii)  
Arctostaphylos. sp. Manzanita
Bambusa sp. Bamboo
Calluna sp. Heather
Cornus sp. (except C. florida and C. capitata) Dogwood
Euryops pectinatus  
Hedera canariensis Algerian Ivy
Hedera helix English Ivy
Helianthemum sp. Sun Rose
Magnolia sp. Magnolia
Morus sp. Mulberry
Philadelphus sp. Mock Orange
Phyllostachys sp. Bamboo
Platanus sp. Plane Tree, Sycamore
Rhaphiolepis indica Indian Hawthorn
Rhaphiolepis umbellata Yeddo Hawthorn
Robinia sp. Locust
Sarcocca sp. Sweet Box
Sassafras albidum Sassafras
Tamarix sp. Tamarisk
Tibouchina urvelleana Pleroma, Princess Flower
Vaccinium sp. Huckleberry

NOT TESTED: MODERATELY RESISTANT (back to top)

*Alnus sp. Alder
*Aralia chinensis Fern-leaf Aralia, Chinese Aralia
*Betula platyphylla var. japonica Japanese White Birch
*Betula szechuanica  
*Buddleja japonica  
*Buddleja officinalis  
*Caryopteris incana Bluebeard, Blue Spiraea
*Cephalotaxus harringtonia Cow’s Tail Pine, Japanese Plum Yew
*Chamaecyparis obtusa Hinoki Cypress
*Cornus capitata Bentham’s Cornus
*Cornus chinensis  
*Corylopsis sinensis var. calvenscens Winter Hazel
*Cryptomeria japonica Japanese Cedar or Redwood
*Desmodium elegans Sugarwood
*Deutzia glomeruliflora  
*Hydrangea aspera  
*Hypericum patulum  
*Idesia polycarpa  
*Indigofera hebepetala  
*Indigofera heterantha  
Indigofera sp.  
*Junierus formosana Taiwan Juniper
*Leptodermis potaninii  
*Ligustrum delavayanum  
*Lindera erythrocarpa  
*Lonicera morrowii  
*Lonicera syringantha  
*Malus sieboldii Toringo Crabapple
*Malus yunnanensis  
*Osmanthus delavayi Delavay Osmanthus
*Philadelphus schrenkii  
*Pterocarya rhoifolia  
*Pyracantha atalantioides  
*Pyrus pyrifolia Sand Pear
*Rhus chinensis Chinese Gall, Nutgall
*Sciadapitys verticillata Umbrella Pine, Japanese Umbrella Pine
*Spiraea henryi  
*Stachyurus praecox  
*Syringa reticulata Japanese Tree Lilac
*Syringa yunnanensis  
*Tsuga dumosa Himalayan Hemlock
*Tsuga forestii  
*Viburnum cinnamomifolium Cinnamon Viburnum
*Viburnum cylindricum  
*Viburnum foetidum var. ceanothoides  
*Weigela decora  
*Weigela hortensis  

NOT TESTED: SUSCEPTIBLE (back to top)

Acer negundo ssp. Californicum CA Box Elder
Begonia tuberhybrida Tuberous Begonia
Camellia sp. Camellia
*Carpinus japonica Japanese Hornbeam
Cedrus deodora Deodar Cedar
Cedrus lebani Cedar of Lebanon
Cedrus lebani ssp. atlantica Atlas Cedar
Citrus sp. Citrus
Cotoneaster gracilis Jade Tree, Jade Plant
Cotoneaster moupinensis Mourning or Chinese Weeping Cypress
Crassula ovata  
Cupressus funebris  
Cyclamen sp. Cyclamen
Dahlia hortensis Dahlia
Erica sp. (except E. arborea)  
Eriobotrya japonica Loquat
*Eurya emarginata  
*Eurya japonica  
Fragaria x ananassa Strawberry
Fuchsia sp. Fuchsia
Gardenia jasminoides Gardenia
Hebe buxifolia Hebe
Hibiscus sp. Hibiscus
Hippiastrum vitatum Amaryllis
*Hydrangea heteromalla  
Hydrangea macrophylla Hydrangea
*Hydrangea paniculata  
Impatiens sodenii  
Iris germanica Flag, Bearded Iris
Juglans regia Persian Walnut
Juniperus sp. Prostrate Junipers
Laurus nobilis Sweet Bay
Ligustrum sp. (except L. Privet
tschonskii and L. japonicum)  
Musa x paradisiacal Banana
Nyssa sp. Tupelo
Olea europea Olive
Opuntia stricta var. dilleni Prickly Pear Cactus
Paeonia lactiflora Peony
Pelargonium sp. Geranium
Quercus kellogii California Black Oak
Rhamnus californicus Coffeeberry
*Rhamnus crenatus  
*Rhamnus japonicus  
Rhododendron sp. Rhododendron, Azalea
Rosa sp. Rose
Rubus sp. (except Merten Thornless, loganberry, ollalieberry)  
Salix pendulina Wisconsin Weeping Willow
*Schima wallichii  
Schinus molle California Pepper Tree
Syagrus rommanzoffiana Queen Palm
Trachelospermum jasminoides Star Jasmine
Zantedeschia sp. Calla
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