Important diseases and decays of trees native to Washington

EXTENSION BULLETIN 540 JULY 1960 AGRICULTURAL EXTENSION SERVICE INSTITUTE OF AGRICULTURA L SCIENCES WASHINGTON STATE UNIVERSITY, PULLMAN , WASHINGTON

Important Diseases and Decays of Trees Native to Washington

c. G. SHAW Professor of Washington State University

M. R. HARRIS Extension Plant Pathology Specialist Washington State University

CONTENTS

BUCKTHORN-Cascara INTRODUCTION ------1 Buckthorn ------7 Leaf Rusc-Puccinia coronata CONTROL METHODS FOR Leaf Spots-Marssonina rhamni, Phyl­ TREE DISEASES ------2 losticta rhamnigena, Septoria blasda­ lei ALDER-Red Alder ______3 Canker-Didymosphaeria oregonensis CEDAR-Alaska Yellow Cedar___ _ 7 Catkin Broom-Taphrina occidentalis Rust-Gymnosporangium nootkatensis Leaf Spots-Cylindrosporium alni, Sep- taria alnifolia -Microsphaera penicil­ CEDAR-Western Red Cedar ____ 8 lata, guttata Brown Cubical Rot-Polyporus sulphur­ White Trunk Rot-Fomes igniaritts­ eus-See discussion on Western Hem­ See discussion on . lock. Cedar Leaf Blight-Didymascella thu­ jina ASH-Oregon Ash ------4 Leaf Blight-Coryneum thujinum Leaf Spots-Cylindrosporium fraxini and Red Brown Butt Rot-Polyporus schwei­ Mycosphaerella spp. nitzii--See discussion on . Powdery Mildew-Phyllactinia guttata­ Red Ring Rot-Fomes pini--See dis­ See discussion on Red Alder. cussion on Douglas Fir. White Mottled Rot-Fomes fraxinophil­ Shoestring Root Rot-Armillaria mellea us -See discussion on Douglas Fir. White Root Rot-Poria subacida - See ASPEN-Golden Aspen ______5 discussion on Douglas Fir. Yell ow Ring Rot-Poria weirii Canker-Valsa nivea, V. sordida Ink Spot-Ciborinia seaveri Leaf Rust-Melampsora albertensis COTTONWOOD-Northern Leaf Spots-Marssonina populi and My­ Black Cottonwood ------9 cosphaerella populorum-See also dis­ Leaf Blister-T aphrina populi-salicis cussion on Red Alder. Leaf Rust-Melampsora occidentalis - Shoot Blight and Scab--Venturia trem­ See discussion on Golden Aspen. ulae Powdery Mildew-Uncinula salicis-See White Trunk Rot-Fomes igniarius discussion on Red Alder. See also discussion on Birch. White Mottled Rot-Fomes applanatus White Trunk Rot-Fomes igniarius - See discussion on Birch. BIRCH-Western Paper Birch ____ 6 Brown Crumbly Rot- ostrea Brown Cubical Rot-Polyporus betulinus DOGWOOD-Pacific Dogwood ____ 9 Leaf Rust-Melampsoridium betulinum Canker-Nectria galligena Leaf Spot-Septoria betulicola Collar Rot-Phytophthora cactorum White Mottled Rot-Fomes applanatus Powdery Mildew-Phyllactinia guttata- -See discussion on Cottonwood. See discussion on Red Alder. White Mottled Rot-Fomes fomentarius Shoestring Root Rot-Armillaria mellea White Trunk Rot-Fomes igniarius -See discussion on Douglas Fir.

iii FIR-Douglas Fir ------10 Brown Felt Blight - Herp otrichia nigra Aleurodiscus Canker- Aleurodisctts am­ - See discussion on Subalpine Fir. orphus-See discussion on Grand Fir. Brown Stringy Rot - Echinodontiztm Bacterial Gall- Agrobacterittm pseudo­ tinctorium-See discussion on West­ tsugae ern Hemlock. Brown Crumbly Rot-Fomes pinicola­ Brown Trunk Rot-Fomes officinalis - See discussion on Grand Fir. See discussion on Western Larch. Brown Cubical Pocket Rot-Trametes Needle Cast- Hypoderma robustum1 Hy­ se-rialis podermella abietis-concoloris Brown Cubical Rot - Polyportts m lph­ Needle Rusts-Nielampsora epitea1 Mel­ ttreus-See discussion on We s t e r n ampsorella caryophyllacearum1 Puccini­ Hemlock. astrttJn epilobii1 Pucciniastmm goep­ Brown Root and Butt Rot-Fomes an­ pertianum, Uredinopsis pteridis nasus- See discussion on Western Pitted Sap Rot-Polyporus abietimts - Hemlock. See discussion on Subalpine Fir. Brown Stringy Rot - Echinodontium Shoestring Root R ot-Armillaria mellea tinctorittm-See discussion on West­ - See discussion on Douglas Fir. ern Hemlock Sooty Mold- Dimerosporitmz abietis Brown Top Rot-Fomes rosem Brown Trunk Rot-Fomes officinalis­ FIR-Noble Fir ______16 See discussion on Western Larch. Dwarf Mistletoe-Arce1!thobittm dottg­ Fl R-Pacific Silver Fir ______16 lasii Aleurodiscus Canker-Alettrodisctts am­ :Nfotded Bark Disease-Stereum sanguin­ orphzts-See discussion on Grand Fir. olentum Needle Cas t- Hypoderma 'robustum1 H'y­ Needle Cast-Rhabdocline psettdotsugae podermella abietis-concoloris, Lopho­ Needle Rusts- Melampsora albe-rtensis1 dermium spp. - See discussion on l\1elampsora occidentalis Grand Fir. Pitted Sap Rot-Polyportts abietintts - Needle Rusts-Melampsorella caryophyl­ See discussion on Subalpine Fir. lacearum, Pttcciniastrum epilobii, Pttc­ Red Brown Butt Rot-Polyportts sch· ciniastrum goepperianum1 Uredinopsis weinitzii pteridis-See discussion on Grand Fir. Red Ray Rot-Polyporus anceps-See Sooty Mold-Dimerosporium abietis discussion on Ponderosa Pine. See discussion on Grand Fir. Red Ring Rot-Fomes pini Red Root and Butt Rot-Polyporus tOJn­ FIR-Subalpine Fir ______16 entosus and var. circinatus Shoestring Root Rot-Armillaria mellea Aleurodiscus Canker-Aleurodisctts am­ White Mottled Rot-Fomes applanattts orphus-See discussion on Grand Fir. -See discussion on Cottonwood. Brown Crumbly Rot-Fomes pinicola­ White Pocket Rot - Fomes nig-rolimi­ See discussion on Grand Fir. tatus Brown Felt Blight-Herpotrichia nigra White Root Rot-Poria sttbacida Brown Stringy Rot - Echinodontium Yellow Ring Rot-Poria weirii tinctorium-See discussion on West­ ern Hemlock. Needle Rusts-Melampsora epitea1 Puc­ FIR-Grand Fir ______14 ciniastrum epilobii1 Pucciniastrum go­ eppertiamtm1 Uredinopsis longimuc­ Aleurodiscus Canker- Aleurodiscus am­ ronata, Melampsorella caryo phyllacear­ orphus ttm-Also see discussion of Needle Brown Crumbly Rot-Fomes pinicola Rusts on Grand Fir.

iv Pitted Sap Rot-Polyporus abietinus Red Brown Butt Rot-Polyporus sch­ Red Ring Rot-Fomes pini---See discus­ weinitzii---See discussion on Douglas sion on Douglas Fir. Fir. Snow Blight-Phacidium infestans Red Ring Rot-Fomes pini-See discus­ sion on Douglas Fir. Shoestring Root Rot-Armillaria mellea HACKBERRY-Western -See discussion on Douglas Fir. Hackberry ------18 Spongy White Rot-Polyporus oregonen­ Powdery Mildew-Uncinula parvula - sis See discussion on Alder. White Mottled Rot-Fomes applanatus -See discussion on Cottonwood. White Pocket Rot-Fomes nigrolimitatus HEMLOCK-Mountain -See discussion on Douglas Fir. Hemlock ------~------18 White Root Rot-Poria subaciia-See Brown Crumbly Rot-Fomes pinicola­ discussion on Douglas Fir. See discussion on Grand Fir. Yellow Ring Rot-Poria weirii- See Brown Felt Blight-Herpotrichia nigra discussion on Western Red Cedar. -See discussion on Subalpine Fir. Dwarf Mistletoe-Arceuthobium campy­ lopodum f. tsugensis- See discussion JUNIPER-Rocky Mountain on Ponderosa Pine. Juniper ------20 Pitted Sap Rot-Polyporus abietinus - Rust Galls-Gymnosporangiurri spp. See discussion on Subalpine Fir. Spongy White Rot-Polyporus oregonen­ sis-See discussion on Western Hem­ LARCH-Alpine Larch ______20 lock.

HEMLOCK-Western LARCH-Western Larch ______21 Hemlock ------18 Brown Crumbly Rot-Fomes pinicola­ Brown Crumbly Rot-Fomes pinicola­ See discussion on Grand Fir. See discussion on Grand Fir. Brown Cubical Pocket Rot-T rametes Brown Cubical Pocket Rot- T rametes serialis- See discussion on· Douglas serialis-See discussion on Douglas Fir. Fir. Brown Cubical Rot-Polyporus sulphur­ Brown Cubical Rot- Polyporus sulph­ eus-See discussion on Western Hem­ ureus lock. Brown Root and Butt Rot-Fomes an­ Brown Trunk Rot-Fomes officinalis nosus Dwarf Mistletoe- Arceuthobium cam­ Brown Stringy Rot - Echinodontium pylopodum f. laricis-See also discus­ tinctorium sion on Ponderosa Pine. Brown Trunk Rot-Fomes officinalis­ Needle and Shoot Blight-Hypodermella See discussion on Western Larch. laricis Dwarf Mistletoe - Arceuthobium cam­ Red Ring Rot-Fomes pini---See discus­ pylopodum f. tsugensis-See also dis­ sion on Douglas Fir. cussion on Ponderosa Pine. Sparassis Root Rot-Sparassis radicata­ Needle Rusts-Caeoma dubium, Urae­ See discussion on Engelmaqn .. . cium holwayi White Pocket Rot-Fomes nigrotimita­ Needle Spot-Dimerosporium tsugae tus-See discussion on Douglas Fir. Pitted Sap Rot-Polyporus abietinus­ White Root Rot-Poria subacida-See See discussion ·on Subalpine Fir. discussion on Douglas Fir. MADRONE-Pacific Madrone ____ 22 Needle Cast- Elytmderma deformans, Collar Rot-Phytophthora cacto·rum Hypodermella concolor, Hypodermella See discussion on Dogwood. montivaga, Lophodermium pinastri, Leaf Rust-Pttcciniastrum sparsum N aemacyclus niveus-See also the dis­ Leaf Spot-Mycosphaerella arbuticola cussion on Ponderosa Pine. Speckled Tar Spot-Rhytisma arbuti Pitted Sap Rot-Polyporus abietinus - See discussion on Subalpine Fir. Red Ray Rot-Polyporus anceps-See -Big Leaf Maple ______22 discussion on Ponderosa Pine. Red Ring Rot-Fomes pini-See discus­ Dotted Tar Spot-Rhytisma punctatum sion on Douglas Fir. Leaf Spot-Cercosporella aceris Twig Blight-Cenangium ferruginosum Leaf Spot-Septaria aceris Western Gall Rust-Cronartium hark­ Nectria Dieback-Nectria cinnabarina nessii-See discussion on Ponderosa Perennial Canker-Nectria galligena - Pine. See discussion on Dogwood. Shoestring Root Rot-Armillaria 1nellea -See discussion on Douglas Fir. PINE-Ponderosa Pine ______25 White Mottled Rot-Fames applanatus -See discussion on Cottonwood. Blister Rust-Cronartium coleosporio­ White Trunk Rot-Fames igniarius ides, Cronartittm comandrae - See See discussion on Birch. discussion on Lodgepole Pine. Wilt-Verticillium albo-atrum Brown Crumbly Rot-Fomes pinicola­ See discussion on Grand Fir. Brown Top Rot-Fames roseus, Fames MAPLE-Vine Maple ______23 subroseus-See discussion on Douglas Fir. Leaf Spot-Septaria ace1'is-See discus­ Brown Trunk Rot-Fames officinalis­ sion on Big Leaf Maple. See discussion on Western Larch. Dwarf Misrletoe-Arceuthobium campy­ lopodum -Oregon White Oak ______24 Needle Cast-Elytroderma deformans Brown Friable Rot-Polyporus spraguei Pitted Sap Rot-Polyporus abietinus­ Frosty Mildew-Microstroma album See discussion on Subalpine Fir. Piped Rot-Polypo1·us dryophilus Red Ray Rot-Polyporus anceps Powdery Mildew- Microsphaera peni- Red Ring Rot-Fames pini-See discus­ cillata-See discussion on Red Alder. sion on Douglas Fir. Shoestring Root Rot-Armillaria mellea -See discussion on Douglas Fir. PINE-Lodgepole Pine ______24 Western Gall Rust-Cronartium hark­ nessii Atropellis Canker - Atropellis pinicola, Atropellis piniphila-See discussion on Western White Pine. Blister Rust- Cronartium coleosporio ­ PINE-Western White Pine ______27 ides, Crona,rtium comandrae Arropellis Canker-Atropellis pi1zicola Brown Felt Blight-Neopeckia coulteri Blister Rust-Cronartium ribicola -See discussion on Subalpine Fir. Brown Crumbly Rot-Fomes pinicola- Dwarf Mistleroe--ArceuthobitJm ameri­ See discussion on Grand Fir. camtm-See discussion on Ponderosa Dasyscypha Canker-Dasyscypha pini Pine. Needle Cast-Bifusella linearis, Hypo­ Leaf Rust-Coleosporittm astemm dermella sp., Lophodermium nitem

vi Pitted Sap Rot-Palyparus abietinus - Brown Trunk Rot-Fames afficinalis­ See discussion on Subalpine Fir. See discussion on Western Larch. Pole Blight-Cause unknown Needle Rust-Chrysamyxa ledicala Red Ring Rot-Fames pini-See discus­ Pitted Sap Rot-Palyparus abietinus - sion on Douglas Fir. See discussion on Subalpine Fir. Red Brown Butt Rot-Palyparus sch­ weinitzii-See discussion on Douglas PI NE-Whitebark Pine ______29 Fir. Blister Rust-Cranartium ribicala- See Red Ring Rot-Fomes pini-See discus­ discussion on Western White Pine. sion on Douglas Fir. Brown Crumbly Rot-Fames pinicala­ Shoestring Root Rot-Armillaria mellea See discussion on Grand Fir. -See discussion on Douglas Fir. Brown Felt Blight-Neapeckia caulteri White Root Rot-Poria subacida-See -See discussion on Subalpine Fir. discussion on Douglas Fir. Needle Cast-Laphadermium nitens - See discussion on Western White Pine. Red Ring Rot-Fames pini-See discus­ sion on Douglas Fir. ------31 Canker-Valsa spp.-See discussion on Golden Aspen. SPRUCE-Engelmann Spruce ____ 29 Leaf Spots-Cylindrasparium salicinum, Broom Rust-Peridermium colaradense Marssanina spp., Pseudapeziza salicis, Dwarf Mistletoe-Arceuthabium campy- Septa glaeum salicis-fendlerianae-See lapadum f. micracarpum-See discus­ also discussion on Red Alder. sion on Douglas Fir. Powdery Mildew-Uncinula salicis-See Leaf Rust-Chrysamyxa weirii discussion on Red Alder. Needle Cast-Laphadermium piceae Rust-Melampsara epitea Sparassis Root Rot-Sparassis radicata Shoestring Root Rot-Armillaria mellea -See discussion on Douglas Fir. Silver Leaf Diseas~Stereum purpureum SPRUCE-Sitka Spruce ______30 Soft White Rot-Daedalea canfragasa Broom Rust-Peridermium calaradense Tar Spot-Rhytisma salicinum -See discussion on E n g e I m a n n White Mottled Rot-Palyparus squam­ Spruce. asus Brown Crumbly Rot-Fames pinicala-­ White Trunk Rot-Fames igniarius - See discussion on Grand Fir. See discussion on Birch. Brown Cubical Pocket Rot-T rametes serialis - See discussion on Douglas Fir. YEW-Pacific Yew Brown Cubical Rot-Palyparus sulphur­ ------32 Needle Blight-Sphaerulina taxi eus-See discussion on Western Hem­ lock. Brown Pocket Rot-Lentinus kauffmanii Brown Root and Butt Rot-Fames an­ KEY TO THE FRUITING BODIES nosus- See discussion on Western OF FUNGI COMMONLY AS­ Hemlock. SOCIATED WITH DECAY .... 33

Vll

INtRODUCTION

Only the most important diseases of · Many parasitic fungi are able to grow trees native to Washington are discussed on dead twigs and on wood or in · the in this bulletin. No attempt has been soil after the host has been killed. If made to describe or even list all of the later brought into contact with suitable diseases occurring on any of our tree hosts they can again become parasitic. species. On such trees as Western White Some parasites are able to attack only a Pine and Grand Fir more than a hundred single tree species, others can attack only different diseases and decays are known closely related hosts such as pines, while to occur within Washington State. For­ still others can attack a wide range of tunately, most of these diseases are of trees including both and hard­ minor importance and are seldom found. woods. The diseases listed for each tree species and bacterial parasites can at­ are the more important ones and include tack their hosts only under favorable con­ those most likely to be found by owners ditions. First the parasite must be in of farm woodlots and forested areas. contact with the host. The parasite may grow through the soil from the roots of Frequently the same disease or a group one infected tree to another. Or, repro­ of very similar diseases occurs on a num­ ductive structures (usually ) of the ber of different trees. To conserve space parasite may be distributed by wind, and to permit more tJhorough discussion splashing rain, insects, animals, or man. of each disease, readers will find only Even after the parasite has come in con­ one description of such diseases in this tact with a suitable host, environal con­ bulletin. This description is given under ditions, particularly moisture and tem­ the tree on which the disease is most perature, must be suitable for its growth prevalent. The disease is then listed un­ and development before it can become der each of the trees on which it occurs, established on the new host and cause with a cross reference to the complete disease. treatment. Viruses are minute infectious particles Only diseases of native trees have been much smaller than bacteria. They multi­ discussed. Diseases of introduced tree ply rapidly in their host plants. They are species, widely planted in the state for transmitted primarily by insects and by shade and ornamental purposes, will be grafting. Although many virus diseases the subject of a future bulletin. cause serious damage in our fruit orch­ ards, none of the diseases ·of our native Diseases of trees, like diseases of other forest trees in this area are known to ·be plants, are caused by fungi, bacteria, caused by viruses. ·: · .-·' · viruses and unfavorable site and climatic Lack of nutrients, prolonged drought, factors. unseasonably high temperatures, extreme Fungi and bacteria are unable to man­ cold and very early and late frosts as ' well ufacture their own food. They obtain as other climatic factors may cause: dam­ the food necessary for their existence and age to trees. However, native species are growth from other living or dead or­ generally less adversely affected by such ganisms. In the process of obtaining factors than are introduced species since food, parasites almost always weaken and native trees withstand the extremes of injure their host. climate occurring within their range. CONTROL METHODS FOR TREE DISEASES

Control measures have not been work­ widely used is Bordeaux paint prepared ed out for many of the diseases of our with linseed oil. forest trees. The only practical control Bordeaux paint is made by slowly ad­ measures for most diseases are those ding commercial Bordeaux powder to which can be incorporated with stand linseed oil. As the powder is added stir improvement cuttings. Because of the the linseed oil constantly, until a thick greater value of shade and ornamental creamlike mixture results. If, after it has trees, more costly control measures such stood for a short time, the mixture seems as spraying and dusting or pruning and thin, add additional Bordeaux powder wound dressing are warranted. and restir. PRUNING This Bordeaux paint is applied to the Pruning, if properly carried out, re­ wound surface with a stiff brush. A moves much diseased tissue. This im­ single application may remain effective proves the appearance of the affected for several seasons. However, each treat­ trees and prevents the spread of the ment should be examined after six to parasite from diseased to healthy parts twelve months for breaks or peeling. If of the rree and from diseased to healthy the dressing is found to be defective, any trees nearby. The material removed should loose or blistered material should be be burned promptly. Otherwise the prun­ scraped away and a new dressing applied. ings may serve as a source of infection. SPRAYS AND DUSTS Pruning should be performed so that the Fungicides mentioned in this bulletin wound area is kept to a minimum. How­ are Bordeaux mixture, fixed copper, Fer­ ever, cuts involving the removal of entire bam, sulfur, lime-sulfur, and Spergon. branches should be made flush with the All of these are standard materials which trunk. Pruning rools must be sterilized can be obtained in stores handling agri­ after each cur ro prevent the spread of a cultural chemicals. parasite. Dipping pruning tools in de­ Bordeaux spray is made by dissolving natured alcohol is one of the simplest copper sulfate in water and also making means of sterilization. a mixture of freshly slaked lime in water. WOUND DRESSING Ordinarily the copper sulfate is thorough­ Pruning curs and other wounds, if not ly dissolved at the rate of 3 pounds in treated, may serve as entryways for many 5 gallons of water, and the lime is dis­ parasites, particularly the wood decay solved or mixed in water at the rate of fungi. Irregular wounds should be trim­ 3 pounds in 5 gallons of water. These med evenly to remove loose or injured are srock solutions. When each stock bark. On the main trunk the wounded solution is thoroughly mixed, they should area should be cut to a more or less egg­ be added separately to 40 gallons of shaped form. water. It doesn't matter which is added The wound should then be treated with to the water first as long as they are nor a wound dressing to prevent infection poured in together. However, the lime and to promote healing. The larger the should be strained ro remove any lumps. wound the more important it is that a When the mixture is completely com­ wound dressing be applied. Many dif­ bined it is ready for spraying. Three ferent compounds have been employed pounds of copper sulfate and 3 pounds for this purpose, including asphalt and of lime to 50 gallons of water ( 3-3-50 ) creosote compounds, spar varnish, shellac, is a standard formula. Bordeaux mixture rubber latex, melted beeswax and other can be made much stronger than this or grafting waxes. One of the best and most can be reduced in strength if it should

2 burn the trees to which it is applied. not desirable in some instances such as Usually in nurseries 3-3-100 Bordeaux is on Christmas trees but will not damage about as weak as can be used to control ordinary forest trees. leaf fungi. Sulfur is a fungicide which has been Whatever the strength desired, smaller used for many years on many crops. It is quantities than 100 gallons of Bordeaux especially valuable in controlling rusts spray can be prepared by reducing pro­ and mildews. It is usually used in pure portionately the amounts of water, cop­ form as a dust on the foliage and is per sulphate and lime used. However, if valuable in nhe control of certain diseases only a few gallons of spray are required, of forest trees. it is more practical to purchase prepared Lime-sulfur has been used for many Bordeaux mixture than to mix it. Fixed years to control diseases and some insects copper preparations can be used as a sub­ on crops, particularly orchard trees. It is stitute for Bordeaux. used in forestry disease control for mil­ Perham or ferric dimethyldithiocarba­ dews and some of the insects which affect ma:te is a black, wettable powder which trees. It is not poisonous to humans and is not toxic to most plants and animals. is particularly valuable as a dormant It is used to control diseases on many spray. crops and can be applied either as a Spergon or tetrachloro-para-ben·zoqui; spray or a dust. As a spray it is usually none is a yellow powder used for seed applied at the rate of 1 Y2 to 2 pounds in treatment. The material is dusted on the 100 gallons of water. Dust preparations seed. It is usually used at the rate of 7 usually contain 10 to 15 per cent of the ounces for 100 pounds of seed on small active ingredient. It controls damping­ seeds and 3 ounces per 100 pounds on off and other diseases in the soil. Since large seeds. It is a seed-treatment chemi­ it produces a dark residue on foliage it is cal, and is seldom used for other purposes.

ALDER-Red Alder Alnus rubra CANKER ated and project as curled red tongues. Didymosphaeria oregonensis When the fungus is sporulating ~hese Only young trees are affected. Cankers enlarged scales appear whitish, while' with appear on the trunks and branches and age they become dark brown. cause stunting and deformation. Rough­ Control: Damage to the tree is slig:1r. ened bands of bark varying from Y2 On ornamentals the infected parts may inch to over 2 feet in length indicate the be removed by pruning. cankered areas. The cankers are occa­ LEAF SPOTS sionally accompanied by spindle-shaped Cylindrosporium alni swellings. Black to dark brown fungus Septoria alnifolia fruiting bodies of pinhead size are pro­ Brownish areas varying in size and duced on the margins of the canker. shape appear on the leaf surface. The Control: No control measures have dead areas may fall out, leaving ragged been developed, but if infection is seri­ holes. The fruiting structures of the ous, pruning or the complete removal of fungus appear as minute dark dots scat­ heavily infected trees may prevent fur­ tered over the infected area or grouped in ther spread. the center of the spot. CATKIN BROOM Control: Dead leaves on the ground T aphrina occidentalis should be raked and burned. If the di­ The scales of the infected female cat­ sease. is severe on shade and ornamental kins become much enlarged and elong- trees, spray with a copper or dithiocarba-

3 mace ( Ferbam) fungicide just a the buds during dry weather. Late in the season, are opening and again after 10 days. minute dots that are initially yellowish Co ntrol is not praccical in forest scands. or orange red begin to appear on the my­ celium. These strucrures are the over­ POWDERY MILDEW wintering fruiting bodies. They become Microsphaera penicillata black as they mature. From these fruiting P hyllactinia guttata bodies a second type of is released Powdery mildew occurs on many dif­ in the spring. These spores cause the ferent species of forest trees. The sur­ initial infections the next season. On faces of infected leaves are covered with some hosts the fungus may also over­ a white cobweb of threads ( ) winter under the bud scales. ·which becomes powdery as spores de­ Control: Gather and burn fallen leaves. Yelop. Phyllactinia guttata usu ally de­ Dust the foliage with sulfur or spray velops on the under side of the leaves, with lime-sulfur. Control is not practical but most other powdery mildews are in forest stands. found on the upper surface. Develop­ WHIT E T RUNK ROT ment of the mycelium on the surface Fames igniarius may be pronounced during periods of See the discussion of this decay on high humidity, and almost unnoticeable Birch.

ASH-Oregon Ash Fraxinus oregona

LEAF SPOTS the buds open and 10 days to two weeks Cylindrosporium fraxini later with a dithiocarbamate or copper Mycosphaerella effigurata ( includ­ spray. ing Marssonina fraxini and POWDERY MILDEW Piggotia fraxini ) Phyllactinia guttata Mycosphaerella fraxinicola ( in- See discussion of Powdery Mildew on cluding P hyllosticta viridis ) Red Alder. The leaf spot caused by Piggotia frax­ WHITE MOTTLED ROT ini ( M ycosphaerella effigurata) is char­ Fames fraxinophilus acterized by the profuse development of The diseased wood is initially brown­ black fruiting bodies which usually run ish with white spots. later the wood be­ together to form black crusts on the comes straw colored or white, soft and under surface of the leaves. The infected crumbly. The fruiting bodies are either areas become a lighter green or yellow hoof shaped or shelf-like. They are peren­ color. nial, hard and woody. The upper surface The Cylindrosporitmz and Phyllosticta is rough and dark brown or black. The leaf spots cause indefinite brown blotches. under surface is brownish and covered Here the fruiting bodies are visible as with small pores. The conks may be a distinct, minute dots on the brown areas. foot or more in diameter. They are They are light colored and on the upper usually located where dead branch srubs surface on Cylindrosporittm spots and were previously present. black and on the lower surface on Phyl­ C antral : Prevent wounding of shade losticta spots. trees and surface sterilize wounds that do Control: N ot practical, except on valu­ occur. In forest stands, the only practical able shade trees. Rake and burn fallen control is removal of infected trees during leaves. When serious, spray at the time stand improvement cuttings.

4 ASPEN-Golden Aspen tremuloides CANKER fungus, since the sclerotia are easily dis­ Valsa nivea ( including Cytospora lodged from the leaves and remain on nivea) the surface of the soil. Valsa sordida (including Cytos­ LEAF RUST pora chrysosperma) Melampsora albertensis Lesions or cankers appear on the trunk Yellowish spore-producing pustules and larger limbs. Smaller branches and ( uredia) are produced on the under sides twigs are killed without canker formation. of the leaves. Later in the season slightly The bark of the circular or irregular raised, red-brown crusts ( telia) are form­ cankered area is usually brown and ed on the under surfaces. The alternate sunken. The cankers gradually enlarge host of this rust is Douglas Fir. until they girdle the limb or trunk. The Control: Damage is rarely severe sapwood under the canker becomes in­ enough to justify control measures. In fect·ed and even the heartwood may be nurseries, Aspen should be separated discolored. Small, raised, blackish, pim­ from Douglas Fir by at least several ple-like fruiting bodies (pycnidia) appear hundred feet. in the diseased bark. During prolonged LEAF SPOTS periods of high humidity, long, coiled, Marssonina populi yellow to reddish-orange spore tendrils Mycosphaerella populorum (in­ emerge from these pycnidia. Spores are cluding Septaria musiva) also liberated during rainy weather, burt Forming irregular, brownish to black­ tendrils of spores do not form. The sec­ ish spots. See discussion of Leaf Spots ond spore stage (the perithecia) is less on Red Alder. frequently produced and, being more SHOOT BLIGHT AND SCAB deeply embedded in the bark, is less con­ Venturia tremulae (including spicuous. Pollaccia radios a) Cnntrol: The disease is most serious Blackening and wilting of young leaves in stands of low vigor. Control is not and entire young shoots characterize the practical under forest conditions. High disease. The fruiting bodies on the living vigor should be maintained in ornamental leaves produce dark olive-green masses of trees, and these should be watered during spores. dry periods. Avoid wounding. If prun­ Control: Not practical under forest ing is done, use disinfected tools and conditions. On ornamental trees prune dress the pruning wounds with antiseptic and burn infected shoots, and rake and waterproof paint. burn fallen leaves. If severe, the use of INK SPOT Spergon or lime-sulphur should control Ciborinia seaveri the disease. Round to oval spots are produced on WHITE TRUNK ROT the leaves. The centers of these spots Fomes igniarius develop into hard, black masses com­ On Aspen three stages of decay have posed primarily of fungus tissue. These been recognized. In the beginning stage structures, known as sclerotia, fall out of the wood is light pink to straw-brown the leaves resulting in a shot-hole effect. colored; in the intermediate stage the The sclerotia serve to carry the fungus wood becomes chocolate brown; and in over the winter. the advanced stage it is soft, punky and Control: No practical control measures varies from brown to white in color. are known. Raking and burning infected See the discussion of White Trunk leaves does not result in removing rhe Rot on Birch. 5 BIRCH- Western Paper Birch Betula papyrifera BROWN CRUMBLY ROT host is not known to occur in the Pacific Sterettm ostrea Northwest. The rust is apparently per­ This decay attacks both heartwood and petuated from year to year by the uredos­ sapwood, causing a brown crumbly rot. pores. The annual fruiting bodies (conks) are Control: The rust is of no economic thin, leathery, shelf-like brackets, one importance. above another. The upper surface is buff LEAF SPOT colored, bur becomes gray with age. The Septaria betulicola under surface is light brown and smooth. Irregular brown spots, lA to Y2 inch C antral: On shade and ornamental in diameter, with reddish-brown margins trees, wound surfaces should be disin­ are produced. The fruiting bodies of fected promptly. In forest stands, infected the fungus are visible as minute black trees should be removed during improve­ dots on the upper surface of the dead ment cuttings. areas. Control: Not serious enough to war­ BROWN CUBICAL ROT rant control. Polyporus betulinus Decayed wood is yellowish brown and WH ITE MOTTLED ROT usually cracked, with thin white sheets Fames app lanatus composed of fungus mycelium in the See discussion of White Mottled Rot cracks. The wood is light in weight and on Cottonwood. powders easily under pressure. WH ITE M OTTLED ROT The fruiting bodies (conks ) are an­ Fames fomentarius nual, corky and either shelf or hoof The rot caused by this fungus is sim­ shaped. The upper surface is smooth ilar to that caused by Fornes applanatus. and gray. The outer margin curves in­ and on the basis of the rot alone it is ward toward the under surface. The difficult to distinguish between the two. lower surface is yellowish white when Infection of living trees takes place fresh, becoming brown with age and is through branch stubs and wounds. The composed of small pores. The pore heartwood and occasionally the sapwood layer breaks away easily from the rest are attacked. of the conk. The conks are perennial and hoof Control: On shade and ornamental shaped. The upper surface is smooth, trees, wound surfaces should be disin­ gray to grayish brown, and concentrically fected promptly. In forest stands, in­ zoned. The under surface is brown with fected trees should be removed during small circular pores. The interior of the improvement cuttings. conk is dark brown and the tubes (pores ) appear extremely long, annual LEA F RUST layers not being conspicuous as in many Melampsoridium betztlinum other perennial conks. The tubes are Small, round, reddish-yellow, powdery often encrusted with white material. pustules (uredia) appear on the under Control: Same as for White Mottled surfaces of the leaves in the summer. In Rot caused by Fames applanatus. In for­ early fall, waxy yellow to brown crusts est stands remove infected trees during ( telia ) appear on the lower surfaces of improvement cuttings. Prevent wound­ infected leaves. The alternate host of ing of ornamental trees; sterilize pruning this rust is larch, but infection on this tools and wounds.

6 WHITE TRUNK ROT They may reach a width of 8 inGhes, but Fomes igniarius usually average about 4 inches. The up­ White Trunk Rot is a heart rot occur­ per surface of young conks is grayish ring on many hardwoods. The beginning black and smooth, but with age this sur­ stage is indicated by yellowish-white face becomes rough and cracked. The spots or streaks of varying size in the under surface is brown and possesses in­ heartwood. These areas are usually sur­ numerable minute circular pores. The rounded by a yellowish-green to blackish­ interior of the conk is rusty brown and brown zone. In the advanced stage of shows many layers of tubes. The older decay the wood is light in weight, soft, layers of rubes (pores) contain a white and whitish, but with fine black lines deposit. Conks usually develop from old running throughout the decayed area. wounds or where a limb has broken off. The rot continues to spread after a tree Control: On shade and ornamental dies and may eventually involve the en­ trees, wound surfaces should be disin­ tire tree. fected promptly. In forest stands, in­ The conks (fruiting bodies) are hard fected trees should be removed during and woody and usually hoof shaped. improvement cuttings. BUCKTHORN-Cascara Buckthorn purshiana LEAF RUST LEAF SPOTS Puccinia coronata Marssonina rhamni Phyllosticta rhamnigena The yellow to orange-yellow fruiting Septoria blasdalei bodies are formed on the underside of The spots caused by these fungi are the leaves. The individual fruiting bodies similar in appearance and can be dis­ are cup shaped. Usually they are closely tinguished only by microscopic examin­ grouped together into what is called a ation of the fruiting bodies and their cluster cup. The leaf tissue bearing the spores. The spots are gray to brown and cluster cups becomes somewhat thick­ circular to irregular in shape. The fruit­ ened and distorted and eventually dies. ing bodies are produced on the upper Alternate hosts for this rust are cultivated surface of the leaf and can usually be oats and several wild grasses such as seen as minute dots in the center of velvetgrass, bluejoint, western bentgrass, the spots. and ryegrass. Control: While these spots are of no Control: Where farmers are growing economic importance, when severe they oats, this rust can cause serious loss to do result in unsightly appearing orna­ the oat crop. Consequently, buckthorn mental shrubs. No control measures have should be completely eliminated in such been worked out, but two or three copper areas. There is no practical control for sprays applied at 10-day intervals should the rust on buckthorn. provide control. CEDAR-Alaska Yellow Cedar C bamaecyparis nootkatensis RUST yellow. The alternate host of this rust is Mountain Ash ( S or bus sp.) . Gymnosporangium nootkatense Control: Not practical under forest The fruiting bodies occur on the scale­ conditions; in nurseries and ornamental like leaves. The spore masses are bright plantings, separate the alternate hosts by orange when fresh, but soon become pale at least Y2 mile.

7 CEDAR-Western Red Cedar T huja plicata BROWN CUBICAL ROT RED RING ROT Polyporus su!phureus Fomes pini See the discussion of this decay on See the discussion of this decay on Western Hemlock. Douglas Fir. CEDAR LEAF BLIGHT Didymascella thujina SHOESTRING ROOT ROT This disease may affect trees of all Armillaria mellea ages, but is most serious on seedlings See the discussion of this decay on and saplings. The disease is favored by Douglas Fir. prolonged periods of high atmospheric humidity. Seedlings less than four years WHITE ROOT ROT of age may be killed in a single year if Poria subacida the disease is epidemic. On larger trees, See the discussion of this decay on usually only the lower branches become Douglas Fir. infected. The twigs appear as though scorched by fire. In late autumn the YELLOW RING ROT smaller twigs drop, leaving bare branches. Poria weirii The fruiting bodies of the fungus are This rot is usually confined to the conspicuous on the upper surfaces of the roots and the first 10 feet of the butt flat leaves. They are cushion-like and log. A yellowish discoloration in the elevated when wet, but become depressed brown heartwood marks the beginning when the air is dry. These fruiting struc­ stage. As the discoloration becomes more tures are olive brown when young, be­ pronounced, the wood softens. The spring coming black with age. late in the sea­ wood disintegrates more rapidly than son the fruiting structures fall out, leav­ the summer wood in each annual ring, ing holes in the leaves. with the result that a typical ring rot Control: Control is practical only in results and the annual rings of the wood nurseries, where Bordeaux mixture ( 3- separate. The rotted wood finally be­ 3-50 ) should be applied several times comes a brown stringy mass, which may during the summer and the fall. completely disintegrate, leaving a cone­ LEAF BLIGHT shaped hollow. C oryneum thujinum The perennial conks, which range in This disease is of minor importance color from light to dark brown, form except when found on nursery stock. flat crusts and are commonly found in Small black specks appear on the under­ root crotches. The pores are small and surfaces of the leaves. This disease often numerous. A new layer of pores is form­ occurs on trees also infected with Cedar ed each year over the pores of the previ­ leaf Blight. ous year. Control: No control has been definite­ ly worked out, but preliminary tests Control: The fungus commonly gains indicate that several applications of Bor­ entrance through basal fire scars and deaux mixture ( 3-3-50 ) during the latter other wounds to the root crown and part of the season will control the disease roors. Prevention of fire and wounding in nurseries. should reduce the incidence of infected RED BROWN BUTT ROT trees. Where this decay has caused seri­ Polyporus schweinitzii ous loss to Cedar or Douglas Fir, it may See the discussion of this decay on be advisable to replant with a less sus­ Douglas Fir. ceptible species, such as Pine.

8 COTTONWOOD-Northern Black Cottonwood Populus trichocarpa LEAF BLISTER WHITE MOTTLED ROT T aphrina populi-salicis Fames applanatus This rot is primarily a butt rot, seldom The leaf blisters are roughly circular extending more than 12 feet up the in outline, thicker than the normal leaf, trunk. It occurs on both hardwoods and and are at first brilliant yellow, later be­ conifers. The wood appears bleached in coming brown. the beginning stage of decay and is bor­ Control: If serious, as it sometimes is dered by a brown band ~ inch or more in nurseries, the disease may be con­ in width. In the advanced stage the wood trolled with Bordeaux spray or sulphur is soft and spongy, creamy in color, with fine black lines running through . it. dust. Applications should be made at the When split lengthwise, the wood shows time the buds br.eak, and repeated at a mottled appearance from which the 10-day to two-week intervals. common name of the rot is derived. The fruiting bodies are shelf-like: The LEAF RUST smooth upper surface is light grayish Melampsora occidentalis brown in color and possesses ·a distinct The signs and symptoms of the Cot­ crust that is harder than the interior of the conk. The under surface is white tonwood Leaf Rust are similar to those when fresh, but when bruised it im­ of the Leaf Rust on Aspen. Further­ mediately turns brown. The color differ­ more it has recently been demonstrated ences between bruised and unbruised that Douglas Fir is the alternate host portions of the under surface are con­ for both of these rusts. See the discussion stant and the conk is often called the of Leaf Rust on Golden Aspen. Artist's Conk. Conks measuring up to 2 feet in width are not uncommon. POWDERY MILDEW Control: In forest stands remove in­ Uncinula salicis fected trees during improvement cut­ tings. Prevent wounding of ornamental See discussion of Powdery Mildew on trees; sterilize pruning tools and wounds. Red Alder. Although the powdery mil­ dew fungus on Cottonwood is a different WHITE TRUNK ROT species from those found on Alder, the Fames igniarius appearance of the disease is similar and See the discussion of White Trunk the same control measures apply. Rot on Birch.

DOGWOOD-Pacific Dogwood C ornus nuttallii CANKER of tarket-like rings or may be completely Nectria galligena covered by old bark. The fruiting bodies The first symptom of this disease is a ( perithecia) are small, red, round bodies small depressed area of bark around a of pinhead size and usually grow in wound or at the base of a dead branch. clusters when present. They may not ap­ The bark over the canker becomes pear on some cankers. darker than normal and cracked at the Control: Prevent wounding; remove edges. Older cankers are often a senes and burn infected portions when feas-

9 ible; sterilize pruning rools; treat wounds Control: No effective control is known with disinfectant wound dressing. In under forest conditions. Avoid wound­ forest stands remove trees showing trunk ing transplanted ornamental trees. Trees cankers during stand improvement cut­ should not be injured by such things as tings. lawn mowers. Small cankers can be gouged out and the wound sterilized. COLLAR ROT Later when the wood has dried out, ap­ Phytophthora cactorum ply a wound cover such as Bordeaux Trees having collar rot are weak and paint. Dead or severely diseased trees lack a full crown of leaves. The remain­ should be completely removed, including ing leaves may turn yellow or red, or the roots, and replaced with nonsuscep­ wilt in spring or midsummer. Twigs or tible species such a conifers. main branches may also wilt and die. A POWDERY MILDEW canker which initially is difficult to de­ Phyllactinia guttata tect develops at the ground line or on See discussion of Powdery Mildew on the roots. When the cankered area is Red Alder. cur open, the bark is found to be brown and dead. Later, the diseased bark SHOESTRING ROOT ROT shrivels, cracks loose, and falls away. Armillaria mellea When the canker encircles the trunk, the See discussion of this disease on Doug­ tree dies. las Fir. FIR-Douglas Fir Pseudotsuga menziesii ALEURODISCUS CANKER BROWN CUBICAL POCKET ROT Aleurodiscus amorphus T1mnetes serialis See discussion of this disease on Grand Following an initial yellowish-brown Fir. discoloration of the wood, pockets of BACTERIAL GALL brown cubical rot develop. The margins A gro bacterium psettdotsugae of the individual pockets are not sharply This is one of the few known bac­ defined and often the pockets grow to­ terial diseases of forest trees. Saplings gether. of reduced vigor are most likely ro be at­ The annual conks are white and leath­ tacked, globose to irregularly shaped galls ery and while usually a few are shelf­ being formed on the trunk and branches. like, many often show no free margin The galls may range in size from a pin­ and are completely adherent ro the log bead ro several inches in diameter. The on which they are borne. Conks usually surface of the galls becomes rough and do not develop on living trees, although spongy. the decay may be extensive. Control: Remove infected trees. On Control: None practical. ornamental trees, the infected branches BROWN CUBICAL ROT may be pruned out with sterile pruning tools. All tools should be resterilized Polyporus sulphureus after each cut and the pruning wounds See the discussion of this decay on surface sterilized. Western Hemlock. BROWN CRUMBLY ROT BROWN ROOT AND BUTT ROT Fames pinicola Fames annostts See discussion of this decay on Grand See the discussion of this decay on Fir. Western H emlock.

10 BROWN STRINGY ROT another year and produce seeds before Echinodontium tinctorium dying. The flowering shoots arise from See the discussion of this decay on an absorbing system produced within the Western Hemlock. infected twigs and this persists indefin­ BROWN TOP ROT itely sending out new aerial shoots each Fomes roseus year. Infected branches eventually de­ The decay is a typical brown cubical velop into conspicuous witches' brooms. rot of the heartwood, usually limited to Infections on the main trunk often result the upper part of the bole. Living trees in ~he death of the crown above the point are infected through broken and dead of infection. branches. In the advanced stage the wood Control: In the areas where Mistletoe is yellowish rto reddish brown, soft when of Douglas Fir occurs it is one of the wet, brittle and crumbly when dry. most serious diseases of this important There may be a zone of greenish dis­ forest tree. Control can be accomplished colored wood at the margin of the de­ only by complete elimination of mistle­ cayed area. toe from the stand. This of.ten can only The fruiting bodies (conks) are be accomplished by clearcutting followed woody brackets, up to 6 inches wide, by artificial reseeding or planting. In­ zoned and rose brown to black on the fected trees should not be left as seed upper surface and rose colored on the trees because lateral spread from a ma­ under surface. The pores are small. ture tree can occur for a considerable Conks are infrequent on trees that are distance. still living, although the rot may be ex­ On ornamental trees Dwarf Mistletoe tensive. After death of the tree, conks can be eliminated by pruning. This are more frequently associated with the should be done in late summer before decay. the berries ripen. Control: In logging operations, avoid MOTTLED BARK DISEASE damage to the tops of trees to be left for Stereum sanguinolentum future cuttings. Remove infected trees The foliage of infected trees turns or trees showing top damage during in­ brown in the late spring or early sum­ termediate cuttings. mer. Examination of the root collar and BROWN TRUNK ROT butt of the tree usually discloses that Fames officinalis considerable resin flow has occurred. See discussion of ~his decay on West­ The bark on the roots and the butt can ern Larch. be easily separated from the wood, and DWARF MISTLETOE 1the inner surface of this bark has a Arceuthobium douglasii mottled appearance. The sapwood may This parasite occurs on Douglas Fir also show the mottling. The sapwood only in the eastern portion of Washing­ finally becomes soft and spongy. ton. The mistletoe plants, which develop The conks of the fungus are thin, flat, on twigs and small limbs, are short, light and leathery. The upper surface is hairy greenish shoots which usually do not ex­ gray in color, and concentrically ringed. ceed 1 inch in length. The leaves are The lower surface is smooth and brown­ small scale-like structur.es. The dwarf ish to purplish black. Conks are rarely mistletoe plants are scattered along the produced on living trees, but they are infected branches, interspersed among common on the exposed roots and the the needles. The plants are of two kinds butts of trees that have been killed. The ( dioecious) and flower in the second fungus is also a common saprophyte year. The male shoots die after flower­ found on dead slash of many coniferous ing, while the female plants persist for species.

11 Control: Prevent basal wounding; re­ distance up tO Y2 mile) 1s impractical move and burn infected trees, including and unnecessary. the stump. PITTED SAP ROT Polyporus abietinus NEEDLE CAST See the discussion of this decay on Rhabdocline pseudotsugae Subalpine Fir. In autumn or early winter yellowish spots appear usually near the tips of the RED BROVVN BUTT ROT needles. By spring the needle spots are Polyporus schweinitzii reddish brown, with sharp borders be­ This decay is found only in the heart­ tween the diseased and the normal green wood of roots and butt logs. It is the tissue. Later the infected needles turn most important burt rot of conifers. The brown for their entire length. In June, beginning stage is marked by yellowish­ fruiting bodies of the fungus can be seen tO reddish- brown discolored streaks breaking through the leaf surface. which extend ahead of the advanced de­ Shortly after this all the infected needles cay for several feet. Advanced decay fall. Late in the season it is difficult to is red brown to yellow brown and detect the disease except by the scarcity soft and cheesy, becoming brittle on dry­ of needles. ing. The rotted wood breaks into cubes Needle Cast is severe on young trees and can be crumbled to a fine powder. and in recent years it has become a seri­ Thin crustlike layers of mycelium form ous problem in Christmas tree planta­ in the shrinkage cracks. tions as well as in nurseries. Older trees The annual fruiting bodies (conks) are attacked, but usually only the lower develop in the fall during wet weather. branches are involved and the injury is When formed on the butt of the trunk slight. they are thin brackets often growing one above another. When they arise through Control: Several applications of Bor­ the soil they are circular in outline, the deaux mixture ( 8-10-100 ) at two-week center of the top is often sunken, and intervals starting about the first of June the conks are stoutly stalked. The upper should control the disease in nurseries surface is velvety, circularly zoned, and and young plantations. Some strains of reddish brown with a light yellow-brown Douglas Fir are resistant and seed from edge. Viewed from below, fresh conks resistant trees should be used in nur­ are a dirty green. The pores on the lower series whenever possible. surface are large and irregular in shape. NEEDLE RUSTS The lower surface becomes reddish Melampsora albertensis brown if bruised. With drying and aging Melampsora occidentalis the conks vary in color from yellow to The orange- yellow fruiting bodies red brown, finally becoming almost ( aecia) are on the undersides of the black. current season's needles. They are round Control: Prevent injury to the butt, to elliptic and arranged in two rows. The particularly fire scarring. Remove dis­ two species can be distinguished only by eased trees during improvement cuttings. microscopic examination of the spores. RED RAY ROT The alternate hosts for the two rusts are Polyporus anceps Golden Aspen ( Populus tremuloides ) See discussion of this decay on Pon­ and Cottonwood (Populus trichocarpa ) derosa Pine. respectively. RED RING ROT Control: These rusts normally cause Fames pini little damage to Douglas Fir. Control Losses from Red Ring Rot exceed (removal of the alternate hosts for a those from any other decay. It has been

12 reported to occur on practically all coni­ Conks growing from the base of the fers of the Pacific Northwest. tree are bracket-like, while those that The beginning stage is marked by a come up through the soil from the roots discoloration of the heartwood, the color are stalked and depressed at the center. varying with the tree species being at­ The annual conks vary from yellow to tacked. In Douglas Fir it is reddish light brown in color and measure from purple, while in other species the color 2 to 3 inches in height and width. The varies from pink through reddish to red upper surface is velvety; the lower sur­ brown. In the advanced stage the decayed face contains small pores. wood contains numerous spindle-shaped Control: No practical control measures pockets usually filled with white masses are known. of cellulose. Some of the pockets may SHOESTRING ROOT ROT be empty. The wood between the pockets Armillaria mellea is apparently sound, but may contain This fungus attacks many species of considerable resin. Seen in cross section, hardwoods and conifers. The fungus is the rot often appears as a series of rings widespread as a saprophyte and apparent­ as a result of the spring wood being ly becomes parasitic only on trees suffer­ destroyed more rapidly than the summer ing a decline in vigor from o~her causes. wood. The cambium and inner bark of the Occasionally the sapwood of living roots and root collar are attacked, the trees may also be rotted after the fungus bark being decayed. In conifers there has caused extensive decay in the heart­ may be an abnormal flow of resin from wood. the root collar. Between the dead bark The fruiting bodies (conks), which and the wood, white fan-shaped mycelial are produced where branches have broken felts are formed. Also black, shoestring­ off, are variable in size and shape. They like runners develop on the surface of may be bracket-like, hoof shaped, or the roots and spread into the surrounding quite thin. Conks vary in width from soil as well as between the bark and the 1 to 8 inches. The upper surface is wood. It is from these structures that the rough, concentrically ridged, and grayish decay derives its name. to brownish black, being darker in the Both the sapwood and the heartwood central, older portion. The margin of are decayed. The wood initially appears living conks is velvety and light golden watersoaked and then becomes light brown. The lower surface is usually rich brownish. In the advanced stage the brown. The pores are extremely variable wood is soft and spongy, yellowish in in size and shape. color, often stringy in conifers, and mark­ Control: No effective control measures ed by numerous black zone lines. This are known. Trees bearing conks should decay spreads up the trunk from the root be removed at the time of improvement collar, sometimes to a height of several cuttings. feet. Infection of the roots and root collar RED ROOT AND .BUTT ROT is followed by a decline in vigor of the Polyporus tomentosus tree as a whole. The leaves may turn Polyporus tomentosus var. yellow and fall prematurely, or all the ci1'cinatus foliage may die almost simultaneously. This decay is similar to Red Ring Rot The fruiting bodies of this fungus are caused by F omes pini. In the beginning typical mushrooms and are edible. The stage the wood is dark red brown, while upper surface is honey colored, the gills in the advanced stage elliptic white are white, and there is an indistinct ring pockets are found. surrounding the stem. While the pro-

13 duction of these fruiting structures is a WHITE ROOT ROT certain indication of Shoestring Root Poria subacida Rot, it is nor a reliable warning of the This decay is restricted to the roots disease, since fruiting bodies may not be and butt area, where it causes a soft, produced until the infected trees have spongy, white rot. Infected trees are pre­ been completely killed. disposed to windfall. At fi rst the wood Control: Control is generally not prac­ is faintly darker than normal. Later, tical in established stands. In replanting, irregular pockets develop in the spring­ select proper sites favoring vigorous wood. T hese pockets run together, form­ growth of the tree species involved. In ing bunches of white fibers. Finally all ornamental plantings, the removal of in­ of the wood is a watersoaked, white, fected trees followed by trenching to stringy mass. prevent the spread of the shoestring-like The annual, crust-like fruiting bodies rhizomorphs is recommended. If infec­ (conks ) are produced on the under sur­ tion is discovered in individual orna­ faces of root crotches and exposed roots mental trees before it has progressed too of living trees. On fallen, infected burt far, the diseased bark and wood showing logs the conks may form sheers extend­ indication of decay should be removed. ing for several feet along the under sur­ The wound should then be treated with face. The conks are cream yellow and a waterproof antiseptic dressing. After vary in thickness, depending on age, up treatment the diseased portions of the ro 0-4 of an inch. The pores on the lower roots and root crown should be left ex­ surface are minute. posed for the rest of the season. Control: Protect trees against basal WHITE MOTTLED ROT wounds; remove trees showing such Fomes applanattts wounds during thinning operations and See the discussion of this decay on improvement cuttings. Cottonwood. WHITE POCKET ROT YELLOW RING ROT Fomes nigrolimitattts Poria weirii The White Pocket Rot produced by On Douglas Fir this rot of the roars this fungus is similar to that produced and butts is a serious threat to reproduc­ by Fomes pini, the Red Ring Rot fungus, tion of trees 20 ro 60 years old. The but the pockets are characteristically growth of the tree is retarded, the needles wider and longer, reaching a length of thin our and those remaining become 2 inches. brown, and the tree dies. Often just The perennial conks are brown and before death a heavy crop of cones is usually crustlike, with at most only the produced. Frequently, weakened trees margin free. Conks are produced on the are blown over before they die. The ror underside of fallen logs and branches. often attacks large groups of trees at the The pores on the lower surface of the same time. conks average five to six per millimeter. See also the discussion of this decay Control: None recommended. on Western Red Cedar. FIR-Grand Fir Abies grandis ALEURODISCUS CANKER suppressed trees and forms cankers on Aleurodiscus amorphus the main stems of such trees. The cankers The fungus is a common saprophyte are elongate with rounded ends and a and fruits profusely on dead trees and raised edge. The annual fruiting bodies dead branches. It becomes parasitic on of the fungus are light colored, some-

14 what leathery, irregularly circular in out­ BROWN TRUNK ROT line, and measure up to Y3 inch in Fomes officina/is diameter. They develop in large numbers See discussion of this decay on West­ over the cankered areas. Cankers com­ ern Larch. monly surround the stub of a dead NEEDLE CAST branch. Hypoderma robustum Control: Remove infected trees during H ypodermella abietis -concoloris improvement thinnings. Conspicuous, elongate, black fruiting BROWN CRUMBLY ROT bodies are produced on the under sur­ F omes pinicola faces of the needles. Infected needles turn This fungus is the most common conk light brown. Minute, circular to irregul­ in the coniferous forests of the North­ arly shaped fruiting structures are also west. It also is occasionally encountered produced on the upper surfaces of the on a number of the hardwoods. It is needles, but these are not as conspicuous usually found on fallen logs and dead as the much larger fruiting structures on slash and plays an important part in the lower surfaces. Those on the upper wood disintegration. However, it also surface are light colored initially, grad­ causes a heart rot of living trees. In ually turning black with maturity. the early stages of decay the wood is Control: Control is not economically faintly yellowish or brownish. In the feasible under forest conditions. advanced stage the wood is easily powd­ ered between the fingers. As the rotted NEEDLE RUSTS Several different rusts occur on Grand wood shrinks, it breaks into cubes. Fir. It is difficult to differentiate them. Mycelium of the fungus frequently forms The characteristics listed should, however, felts in the shrinkage cracks. help. The conks are variable in appearance. Melampsora epitea-The powdery, or­ Typical ones are somewhat hoof shaped, ange-yellow spore pustules on the under zonate, smooth and gray to black on the surface of the needles of the current upper surface, except for the margin season are circular in outline but without which is often red. The under surface a definite st.erile margin. The alternate is white to light cream in fresh speci­ hosts are . mens, becoming cream brown on drying, and is covered with minute pores. The Melampsorella caryophyllacearum - inner substance ( context) and the tubes This rust is easily recognized by the are light wood colored. witches' brooms it causes. The branches are more numerous, shorter, and thicker Control: Proper slash disposal and the than normal; the needles are very short removal of infected trees during improve­ and yellowish. The alternate hosts are ment cuttings constitute the only practical species of chickweed ( Stellaria spp.) . control measures. A void wounding. Pucciniastrum epilobii-The orange­ BROWN FELT BLIGHT yellow spore pustules are on the under Herpotrichia nigra surface of the current season's needles. Although Brown Felt occurs on Grand The pustules are somewhat elongate and Fir, it is not serious on this species. See have a definite outer layer of sterile the discussion of this disease on Sub­ tissue. The alternate hosts are species alpine Fir. of fireweed (Epilobium spp.). BROWN STRINGY ROT Pucciniastrum goeppertianum - This Echinodontium tinctorium rust cannot be distinguished from the See discussion of this decay on West­ preceding one unless a microscopic ex­ ern Hemlock. amination of the spores is made. The

15 alternate hosts are huckleberries and SHOESTRING ROOT ROT blueberries ( V accinium spp.). Armillaria mellea Uredinopsis pteridis-The spore pust­ See the discussion of this decay on ules are white, in contrast to the orange­ Douglas Fir. yellow pustules of the other species listed above. They are produced on needles one SOOTY MOLD to five years old. Alternate host is brack­ Dimerosporium abietis en fern ( Pteridium aquilinum) . Black patches of mycelium are formed, Control: Control of these rusts is not usually on the underside of the older feasible under forest conditions. In the needles. The fungus is not parasitic on vicinity of forest nurseries and ornament­ the needles, but lives on honeydew se­ al trees, the removal of the alternate hosts creted by insects. Trees covered with this for a distance up to Y2 mile will provide fungus are unsightly but otherwise not effective control. damaged. PITTED SAP ROT Control: Control of insects (aphids) Polyporus abietinus is recommended on ornamental trees. See the discussion of this decay on Control is not practical under forest con­ Subalpine Fir. ditions.

FIR-Noble Fir Abies procera

The diseases known to occur and to be among those discussed on Grand Fir m expected on Noble Fir are included the preceding section.

FIR-Pacific Silver Fir Abies amabilis The diseases most frequently en­ See the discussion of Needle Cast on countered on Pacific Silver Fir also occur Grand Fir. on Grand Fir. The following are reported NEEDLE RUSTS on Pacific Silver Fir. Melampsorella caryophyllacearum Pttcciniastrum epilobii ALEU RODISCUS CANKER Pucciniastrum goeppertianum Aleurodiscus amorphus Uredinopsis pteridis See the discussion of this disease on See the discussion of these rusts on Grand Fir. Grand Fir. NEEDLE CAST SOOTY MOLD H ypoderma robustttm Dimerosporium abietis Hypodermella abietis-concoloris See the discussion of this disease on Lophodermium spp. Grand Fir.

FIR-Subal pine Fir Abies lasiocarpa ALE URODISC US CANKER BROWN CRUMBLY ROT Aleurodiscus amorphus Fomes pinicola See the discussion of this disease on See the discussion of this decay on Grand Fir. Grand Fir.

16 BROWN FELT BLIGHT PITTE~ S~P ROT H erpotrichia nigra Polyporus abietinus The disease occurs at high elevations. This is a very common rot of dead Seedlings, saplings, and the lower coniferous sapwood. It is found on dead branches of larger trees are attacked. trees and slash, and may attack the dead When the snow melts in the spring, a sapwood in the vicinity of wounds on living _trees. The wood initially is yellow dense webby mat of brown to black to tan and somewhat softened. In the mycelium is found enveloping the advanced stage of decay the wood is branches. Both the needles and the twigs spongy and honeycombed with small, are killed, the needles turning light elongate pockets containing white fibers. brown. Enmeshed in the mycelial felt The small, annual, bracket-shaped are the small, black, spherical fruiting conks are hairy, zoned, and grayish in bodies. color on the upper surface. The lower Control: Control is not practical under surface is lavender to purple on fresh specimens, but becomes brown with age. forest conditions. Coniferous nurseries The pores on the lower surface are ir­ should not be established at high eleva­ regular in size and shape. tions or on sites where snow drifts are Control: Control is not possible under likely to occur. If snow accumulation is forest conditions. Wounding of orna­ excessive; the snow should be removed. mental trees should be prevented, and Mulching of the nursery should also con­ such wounds as occur should be protected trol the disease. with Bordeaux paint.

BROWN STRINGY ROT RED RING ROT Fames pini Echinodontium tinctorium See discussion of this decay on Douglas See discussion of this decay on West­ Fir. ern Hemlock. SNOW BLIGHT NEEDLE RUSTS Phacidium infestans Needles covered with snow are attack­ Melampsora epitea ed, turning a soft brown. As the snow Melampsorella caryophyllacearum melts, a white mycelium may be seen on Pucciniastrum epilo bii the browned foliage. The fruiting struc­ Pucciniastrum goeppertianum tures, which appear in the summer and Uredinopsis longimucronata fall on the lower surfaces of the browned Except for the last one, Uredinopsis needles, are circular in outline and black. longimucronata, the rusts commonly oc­ Control: The disease is usually not curring on Subalpine Fir also occur on severe in natural stands, and control is Grand Fir. See the discussion of Needle not feasible, other than the removal of Rusts on Grand Fir. Uredinopsis longi­ obviously infected trees during stand im­ mucronata produces white spore pustules provement cuttings. In nurseries, how­ on the needles of the current season, ever, severe losses may occur once the rather than on needles one to five years disease becomes established. Late fall old as is true of Uredinopsis pteridis. spraying with dormant lime-sulphur has U. longimucronata has as its alternate given good control. At the time of trans­ host the lady fern (Athyrium filix­ planting, the seedling stock should be femina). dipped in lime-sulphur.

17 HACKBERRY- Western Hackberry Celtis douglasii POWDERY MILDEW See the discussion of Powdery Mildew Uncinula parvula on Red Alder.

HEMLOCK- Mountain Hemlock T suga mertensiana All the important diseases reported on DWARF MISTLETOE Mountain Hemlock in this state also Arceuthobium campylopodum f. occur on Western Hemlock. The follow­ tmgensis ing are those diseases most commonly See discussion on Ponderosa Pine. encountered on Mountain Hemlock: PITTED SAP ROT BROWN CRUMBLY ROT Polyporus abietinus Fomes pinicola See discussion on Subalpine Fir. See discussion on Grand Fir. BROWN FELT BLIGHT SPONGY WHITE ROT H erpotrichia nigra Polyporus oregonensis See discussion on Subalpine Fir. See discussion on Western Hemlock.

HEMLOCK-Western Hemlock BROWN CRUMBLY ROT lapping clusters, often contammg 20 to Fames pinicola 50 or more individual conks. The conks See the discussion of this decay on are shelf-like and may possess an indi - Grand Fir. tinct stalk or be completely stalkless. When fresh, the conks are fleshy and BROWN CUBICAL POCKET ROT the upper surface is bright orange red, Trametes serialis the pore-bearing, under surface being See the discussion of this decay on sulphur yellow. As the conks weather, Douglas Fir. they bleach to a dirty white and harden, BROWN CUBICAL ROT becoming brittle and finally chalky in Polyporus sulphureus texmre. The decay is widespread on both con­ Control: Generally not practical. Re­ ifers and hardwoods. In conifers it tends move infected trees during improvement to be restricted to the butt. The decay is cuttings and avoid wounding. similar to Brown Trunk Rot, caused by BROWN ROOT AND BUTT ROT Fames officinalis. Initially the wood is yellowish to reddish brown. As the color Fames anna sus deepens, the wood becomes softer. Even­ This rot is generally limited to the tually the wood becomes a brown crumb­ roots and butt, but may extend into the ly mass, which on drying cracks into trunk. In the early stage the wood re­ cubes of varying sizes. The cracks are mains hard and firm, showing only a filled with mycelial felts of the fungus. pinkish to violet discoloration. Narrow The fruiting bodies ( conks ) of Poly­ elongated pockets separated by firm porus sulphureus develop in large, over- brown wood characterize the advanced

18 stage. These pockets are filled with white anywhere on the trunk of a tree indicates material in which black flecks are present. extensive decay. As the decay progresses, the white pock­ Control: Infection occurs through dead ets grow together. Considerable resin branch stubs, wounds, frost cracks, and flow is often associated with the decay. fire scars. Prevention of injury to young The fruiting bodies (conks) are per­ trees should reduce the percentage of ennial and variable in shape. They are infected trees. No other control measures shelf-like if produced laterally on the are practical. trunk or roots, but if produced on the BROWN TRUNK ROT underside of a log or root, there may be Fames o fficinalis no free margin. The upper surface of See the discussion of this decay on the shelf-like conks is zoned and greyish Western Larch. brown in color. The lower surface is cream colored and bears very small pores. OWARF MISTLETOE Arceuthobium campylopodum f. Control: Vigorous stands are not se­ tsugensis riously affected by this rot. Apparently Except that the mistletoe plants are the fungus cannot infect sound roots. slightly smaller (about 2 inches in Consequently, wounding of the roots and length) this mistletoe does not differ the base of the tree should be prevented. materially from that on Ponderosa Pine. See the discussion of Dwarf Mistletoe on BROWN STRINGY ROT Ponderosa Pine. Echinodontium tinctorium NEEDLE RUSTS The decay first appears as a slight Caeoma dubium golden-tan discoloration. As the decay Uraecium holwayi progresses, burrows resembling insect These rusts produce yellowish to damage are found. Soon conspicuous rust­ orange pustules ( aecja) on the under red streaks appear followed by a softening surfaces of the needles. A second spore of the wood and a separating of the stage, represented by minute black dots annual rings. Finally the wood is reddish ( pycnia), may or may not be present. brown to brown, fibrous, and stringy. The two rusts are distinguished from As a result of complete disintegration of one another with difficulty without the the decayed wood, the trunk becomes aid of a microscope. The alternate hosts hollow and the tree is subject to wind are not known for either of these rusts. throw. Control: These rusts are not serious enough to require control practices, and The perennial fruiting bodies (conks) none have been attempted. are hard, woody, and hoof shaped. They are usually located at dead branch stubs. NEEDLE SPOT They may range up to a foot in diameter. Dimerosporium tsugae The top is rough and cracked and dull Small black patches occur on the un­ black in color. The lower surface is derside of needles that are a year or more gray white, and covered with hard, coarse, old. thickly set spines of uniform length. Control: Not necessary and not ascer­ When broken open, the interior of the tained. conk is a bright brick-red color. The conks were used by the Nez Perce and PITTED SAP ROT other Indian tribes to make war paint, Polyporus abietinus hence the common name Indian Paint See the discussion of this decay on Fungus. The presence of a single conk Subalpine Fir.

19 RED BRO~N BUTT ROT bearing surface is whiti h to cream col­ Polyporus schweinitzii ored. See the discussion of this decay on Control: No control measures are Douglas Fir. known.

RED RING ROT ~HITE MOTTLED ROT Fames pini Fames applanattts See the discussion of this decay on See the discussion of this decay on Douglas Fir. Cottonwood.

SHOESTRING ROOT ROT ~H I TE POCKET ROT Armillaria mellea Fa mes nigrolimitattts See discussion on Douglas Fir. See the discussion of this decay on Douglas Fir. SPONGY ~HITE ROT Polyportts oregonensis ~HITE ROOT ROT The rot is a soft, spongy, white rot Poria subacida containing numerous black spots scattered See the discussion of this decay on throughout. Douglas Fir. The annual conks measure up to 2 feet YELLO~ RING ROT across and are usually shelf-like. The Poria weirii reddish-black to black upper surface is See the discussion of this decay on lacquer-like, while the lower, pore- Western Red Cedar.

JUNIPER-Rocky Mountain Juniper Juniperus scopulorum RUST GALLS ing structures elongate into orange ro Gymnosporangittm spp. orange-brown, jelly-like columns com­ Galls on the leaves and smaller branch­ posed of spores. es are produced by several different rusts, The several rust species involved all which can be differentiated from one have members of the rose family as another only by microscopic examination alternate hosts. H awthorne ( Crataegus of their spores. The galls produced by spp.) is the alternate host for some, different species vary in size from less Serviceberry ( Amelanchier spp.) and than 1/ 10 inch to approximately 2 inches Mountai n Ash ( S or bus spp.) for others. in diameter. Some are globose, while Control: Usually not necessary. ( If others are typically elongate swellings. Rust Gall is severe on an ornamental Over the surface of these galls the fruit­ juniper, the exact species of the rust ing structures of the rust ( telia) appear involved should be determined before in the spring as dark brown cushions or any attempt is made to remove possible ridges. As the spores mature, these fruit- alternate hosts. )

LARCH-Alpine Larch Larix l yallii

The diseases known to occur and to be among those discussed on Western expected on Alpine Larch are included Larch.

20 LARCH-Western Larch Larix occidentalis BROWN CRUMBLY ROT DWARF MISTLETOE Fames pinicola Arceuthobium campylopodum f. See the discussion of this decay on laricis Grand Fir. Dwarf Mistletoe is one of the most serious diseases of Larch in northeastern BROWN CUBICAL POCKET ROT Washington. Trametes serialis Except that the mistletoe plants are See the discussion of this decay on slightly smaller (about 2 to 3 inches in Douglas Fir. length) this mistletoe does not differ BROWN CUBICAL ROT markedly from that on Ponderosa Pine. Polyporus su/1Jhureus See the discussion of Dwarf Mistletoe See the discussion of this decay on on Ponderosa Pine. Western Hemlock. NEEDLE AND SHOOT BLIGHT BROWN TRUNK ROT H ypodermella laricis Fames officinalis This disease is often referred to as The decay first appears as a faint needle cast. This is, however, a misnomer, yellowish- or reddish-brown discoloration. since in contrast to the other needle cast The wood softens as the decay progresses. diseases of conifers, the infected needles Finally the wood becomes a brown mass of Larch do not drop off prematurely easily crumbled between the fingers. but rather hang on after the healthy Cracks in the decayed wood are filled needles have dropped. Severely infected with extensive fungus mats, which mea­ stands have a brown, scorched appear­ sure Y3 inch or more in thickness, and ance because of the persistence of the in­ several square feet in area. The decay fected needles. Small, ellipsoid, black produced by Fames officinalis is very fruiting bodies are found on the dis­ similar to that produced by Polyporus colored needles. sulphureus causing Brown Cubical Rot. Control: Control has not been attempt­ The perennial fruiting bodies (conks) ed under forest conditions. In nurseries are variable in size and shape. They may Bordeaux mixture or lime-sulfur applied be cylindrical, hoof shaped, or shelf-like, at two- to three-week intervals from June and measure up to 2 feet in height and through early August is recommended. width. The top is chalky white, smooth RED RING ROT and zoned, or rough with age. The lower Fames pini surface is white with numerous pores. See the discussion of this decay on The interior of the conk is white, soft, Douglas Fir. and cheesy when young, becoming dry SPARASSIS ROOT ROT and chalky with age. The conk is in­ Sparassis radicata tensely bitter to the taste and derives See the discussion of this decay on its common name, the Quinine Fungus, Engelmann Spruce. from its taste. Conks are rarely produced, WHITE POCKET ROT and decay may be extensive even though Fames nigrolimitatus no conk is present. Conks characteristic­ See the discussion of this decay on ally develop at knots or wounds. Douglas Fir. Control: Generally not practical in WHITE ROOT ROT forest stands. Prevent wounding and re­ Poria subacida move infected trees during improvement See the discussion of this decay on cuttings. Douglas Fir.

21 MADRONE-Pacific Madrone Arbutus menziesii COLLAR ROT In the central gray area, minute black Phytophthora cactorum dots, which are the fruiting bodies of the See the discussion of this disease on fungus (perithecia), are just visible to Dogwood. the naked eye. From below the spots are light brown, with a dark brown margin. LEAF RUST Control: Rake and burn fallen leaves. P ~tcciniastrztm sparsum The disease is usually not erious enough The minute, yellowish fruiting bodies to warranc chemical spraying. ( uredia ) are found on the underside of the leaves. They are grouped on irregul­ SPECKLED TAR SPOT arly circular brown spots with purple R hytisma arbuti halos. The spots average Y4 inch in diam­ Numerous irregularly haped, black, eter. There is no known alternate host tar-like spots averaging about Ys inch for the rust in this country; but in in diameter are formed on the lower Europe, Spruce ( Picea sp. ) is the alter­ surfaces of the leaves. A single leaf may nate host. have several clusters of spots. The leaf Control: Usually not necessary. tissue surrounding the rar spots becomes yellowish. LEAF SPOT Control: The disease is of no import­ M ycosphaerella a-rbuticola ance except on shade trees. If control Circular to irregular spots measuring is necessary, fallen leaves should be raked from Y4 to Y2 inch in diameter are and burned; and Bordeaux mixture produced on the leaves. Viewed from should be applied several times at two­ above, the spots are gray at the center week intervals, starting as the leaves with distinct brownish-purple margins. emerge in the spring. MAPLE-Big Leaf Maple Acer macropbyllum DOTTED TAR SPOT LEAF SPOT Rhytisma punctatum Cercosporella aceris N umerous black specks about the size Conspicuous spots about an inch in of a pinhead appear on the upper surface diameter are formed. These often merge of the leaf during the summer. These co involve a considerable area of the specks occur over a circular area Y2 inch leaf. The central portion of the spot is or more wide. The leaf tissue surround­ light brown, the margin dark brown ro ing the black specks becomes lighter blackish. The spots are concentrically green or yellow and this color is retained zoned, the zonations being due to the after the rest of the leaf turns brown in growth of the fungus. the autumn. Control: No control has been worked out. The disease is not serious enough Cont?·ol: Rake and burn infected tO justify spraying. leaves. Several applications of Bordeaux mixture, applied at two-week intervals LEAF SPOT starring as the leaves expand, have con­ Septaria aceris trolled the tar spot disease on some This fungus causes circular, brown hardwoods in nurseries. Such a spraying spots, up to Y2 inch in diameter, on the program should result in control of this leaves. The centers of the spots become disease on shade trees. tan to cream colored and bear minute

22 black dots (the fruiting bodies) on the SHOESTRING ROOT ROT upper surface. Armillaria mellea Control: No control measures have See the discussion of this decay on been worked out. Douglas Fir. WHITE MOTTLED ROT NECTRIA DIEBACK Fomes applanatus N ectria cinnabarina See the discussion of this decay on This fungus is a weak parasite and Cottonwood. usually attacks trees of low vigor. It commonly develops on trees that have WHITE TRUNK ROT suffered severe winter injury. The fungus Fomes igniarius attacks the bark and the sapwood. The See the discussion of this decay on bark in the infected area dies and be­ Birch. comes discolored and sunken as it dries WILT out. Infected sapwood usually becomes V erticillium albo-atrum greenish to blackish in color. As the in­ Verticillium Wilt is characterized by a fection spreads, there is a progressive sudden wilting of all the leaves on one dieback of the twigs and branches. or more large branches of a tree. Several The fruiting bodies ( sporodochia) , branches on one side of a tree may be produced in great profusion on the dead wilted with no wilting of any of the twigs, are coral pink and cushion shaped other branches. The foliage turns yellow and measure about 14 inch in diameter. and finally brown. Discolored streaks are Later, another type of fruiting structure found in the sapwood of wilted branches (perithecium) appears. These are of pin­ and may extend down the trunk and head size, globose in shape and reddish into the roots. These streaks vary in color brown in color. from one host to another, being greenish Control: Control is not practical under in Maple. This wilt organism attacks forest conditions. On shade trees cut out several species of hardwood trees and infected branches and twigs, cutting at also many vegetables and ornamental least 6 inches below any visible indica­ flowers. tion of infection. Burn all infected wood. Control: Not necessary in forest stands. Keep trees vigorous by fertilizing and On shade trees all infected branches watering during the spring and early should be removed and burned. Tools summer, but do not continue these prac­ used should be sterilized and the pruning tices so late in the summer that succulent wounds covered with an antiseptic paint. growth is produced late in the growing Unless it is especially desirable to pre­ season. Mulching to prevent winter injury serve a particular tree as long as possible, is advisable in nurseries and around it is better to completely remove the transplanted seedlings and saplings. infected tree to decrease the likelihood of spread to other trees that are still PERENNIAL CANKER healthy. A void planting ornamentals, N ectria galligena particularly , in soil where suscep­ See the discussion of canker on Dog­ tible crops like potatoes and tomatoes wood. have been grown previously.

MAPLE-Vine Maple Acer circinatum LEAF SPOT See . the discussion of this Leaf Spot Septoria aceris · on Big Leaf Maple. OAK-Oregon White Oak Quercus garryana BROWN FRIABLE ROT PIPED ROT Polyporus spraguei Polyporus dryophiltts The heartwood of the butt and roots Darkened watersoaked areas in the is reduced to a brown crumbly rna s. The heartwood mark the early stage. The ad­ annual fruiting bodies (conks ) are vanced stage of the rot is characterized bracket shaped and up to 6 inches wide. by long, narrow, white pockets. Some of The upper surface is white to grayish these run together at the ides. The wood and somewhat rough. The lower surface between the pockets is firm and brown. is white and contains small pores. The rot column is usually in the main Control: Badly decayed trees should portion of the trunk. be removed. The annual conks are shelf-shaped or FROSTY MILDEW hoof shaped and brown in color. When Microstroma album the conks are cut open, a hard gritty Angular white patches, which repre­ center is found. sent the fruiting stage of the fungus, appear on the lower surfaces of the Control: Generally not practical. leaves. These patches may grow together to form a large discolored area involving POWDERY MILDEW most of the leaf surface. The upper sur­ Microsphaera penicillata face becomes yellowish and mottled. See the discussion of Powdery Mildew Control: Not practical. on Red Alder.

PINE-Lodgepole Pine Pinus contorta ATROPELLIS CANKER guished from one another only by micro­ Atropellis piniphila scopic examination. The alternate hosts

Atropellis pinicola of the first, Cronartium coleosporioides1 See the discussion of this disease on are species of paintbrush (Castilleja spp. ) Western White Pine. and lousewort (Pedicularis spp.); of the second, Cronartium comandrae bastard BLISTER RUST 1 Crona,rtium coleosporioides toadflax ( C omandra spp.) . Cronartium comandrae Control: Although in certain localities Slight spindle-shaped swellings occur these rusts cause severe damage, comrol on the twigs and branches. The orange is seldom practical under forest condi­ frui ring bodies ( aecia) break through the tions. In the vicinity of nurseries, the bark over the swollen area. The blister alternate hosts should be eliminated. cankers are perennial, with new spore­ BROWN FELT BLIGHT producing pustules appearing each year. N eopeckia coulteri The bark becomes cracked and fissured See the discussion of this disease on as the cankers become older; eventually Subalpine Fir. smaller branches and twigs are girdled by the cankers. Porcupines and other DWARF MISTLETOE rodents often eat the cankered bark, Arceuthobium americanum hastening the girdling of the trees. Although the mistletoe attacking The two rusts producing indistinct Lodgepole Pine is a different species spindle-shaped cankers can be distin- than that attacking Ponderosa Pine, the

24 mistletoe itself and the symptoms it RED RAY ROT produces are similar. See the discussion Polyporus anceps of Dwarf Mistletoe on Ponderosa Pine. See the discussion of this decay on Ponderosa Pine. LEAF RUST RED RING ROT C oleosporium asterum Fomes pini The white, tongue-like fruiting bodies See the discussion of this decay on ( aecia) appear on the needles during Douglas Fir. late spring and early summer. The alter­ TWIG BLIGHT nate hosts of this rust are species of Cenangium ferruginosum goldenrod (Solidago spp.) and aster The needles on infected twigs become (Aster spp.) . reddish and drop off. The infection is Control: The disease is not serious usually limited to the current season's enough under forest conditions to justify growth, but may occasionally spread into control practices. the two-year wood or into older portions NEEDLE CAST of the branch. The dead twigs, devoid of needles, are very conspicuous at the end Elytroderma deformans of the growing season. At this time the H ypodermella concolor cup-shaped fruiting structures ( apoth­ Hypodermella montivaga ecia) of the fungus can be found on Lophodermium pinastri the dead twigs. They are black to deep N aemacyclus niveus brown on the outside and greenish yellow Needle Cast symptoms on Lodgepole within. In dry weather these fruiting Pine are similar to those on Ponderosa structures are closed and globose, but Pine, except that no witches' brooms are during wet weather they open and be­ formed on Lodgepole Pine. The fruiting come cup shaped. structures ( hysterothecia) on the needles The disease is generally restricted to are elliptic to elongate, and vary in color trees that have low vigor as a result of from light brown to black. Their size, site or climatic conditions. The disease shape and microscopic characteristics may appear serious and widespread the serve to distinguish the different species first year after a severe winter and then causing Needle Cast. subside during the next growing season. See also the discussion of Needle Cast Control: Not practical under forest on Ponderosa Pine. conditions. PITTED SAP ROT WESTERN GALL RUST Polyporus abietinus Cronartium harknessii See the discussion of this decay on See the discussion of this rust on Pon­ Subalpine Fir. derosa Pine. PINE-Ponderosa Pine Pinus ponderosa BLISTER RUST BROWN TOP ROT Cronartium coleosporioides F omes roseus Cronartium comandrae F omes subroseus See the discussion of Blister Rust on See the discussion of this decay on Lodgepole Pine. Douglas Fir. BROWN CRUMBLY ROT BROWN TRUNK ROT F omes pmicola F omes o fficinalis See the discussion of this decay on See the discussion of this decay on Grand Fir. Western Larch.

25 DWARF MISTLETOE severe on Ponderosa Pine and some A ,rcettthobium campylopodum stands have suffered high mortality as a Dwarf Mistleroe is one of the most result of severe Needle Cast occurring in serious parasites of Ponderosa Pine. In several successive years. many areas in eastern W ashingron more Control: No practical measures for than 50 per cent of the young growth control under forest conditions are is infected. The mistletoe plants are yel­ known. It has been necessary to advance lowish green and about 3 ro 4 inches in the logging schedule in heavily infected height. They characteristically occur in rands to prevent loss. If severe in the clusters arising from a swelling on the nursery, spraying with Bordeaux infected branch. Infected branches often ( 4-4-SO), lime-sulfur ( 2 per cent) or eventually develop prominent witches' with a dithiocarbamate (ferbam) may brooms. Both height and diametral be art em pted. growth, as well as the quality of the PITTED SAP ROT marketable timber, are reduced. Polyporus abietinus Control: Mistleroe can be controlled See the discussion of this decay on only by eliminating it from the stand. Subalpine Fir. In logging it may be necessary to clear RED RAY ROT cut some areas and to re-establish the Polyporus anceps stand by artificial seeding or planting. The early decay is reddish to reddish Trees left after logging for seed pur­ brown and a cross section shows a radiat­ poses should be free of mistletOe. If it ing pattern. The decay is often difficult is necessary ro leave seed trees that are to distinguish from Red Ring Rot; al­ lightly infected with mistletoe, they though in Ponderosa Pine, Red Ring Ror should be removed as soon as satisfactory rends ro be pinkish or red purple. In the reproduction has been established. advanced stage irregular white pockets Mistleroe can be eliminated by cleanup are formed. Black flecks may be present cuttings in young stands that have light in the pockets. Eventually the wood be­ or moderate infection. All heavily in­ comes soft and spongy and disintegrates fected trees and all those with trunk and crumbles easily. infections should be removed. Infected The annual conks of the fungus are branches on lightly infected trees can be rarely formed on living trees. They are pruned off. This work should be done commonly produced on dead slash and in the summer before the berries mature. fallen logs. The conks form cream-colored At this time the mistletoe plants are cmsts on the bark, from which narrow, most easily seen and removal prevents thick brackets protrude. maturation of the year's mistletoe seed. Contro l: The fungus gains entry Some infections will be missed in initial through dead branch stubs, broken tops, cleanup, and one or two more prunings and occasionally through fire scars. Pre­ will be necessary at two-year intervals ro venting injury and fire and the removal effectively eliminate the mistletoe. of infected trees in intermediate cuttings NEEDLE CAST are the only practical control measures. Elytrodernza deformans Numerous, elongate ( Y3 inch or RED RI NG ROT more ), black fruiting bodies occur on Fames pini all surfaces of the needles. These appear See the discussion of this decay on on the two-year-old needles and, as they Douglas Fir. develop, the needles turn brown and fall. SH OESTRING ROOT ROT The fungus also penetrates the twig Armillaria mellea tissue and causes the formation of See the discussion of this decay on witches' brooms. The disease is locally Douglas Fir. 26 WESTERN GALL RUST coleosporioides and C. comandrae) pro­ Cronartium harknessii duce spindle-shaped galls. The spores ( aeciospores) produced in Globose galls, varying in size from Y2 the orange pustules are able to infect not inch to almost a foot in diameter, are only the alternate hosts (reported to be produced. The smaller galls appear on paintbrush, lousewort, etc.) but also pine three- or four-year-old twigs. They con­ itself. In this respect; Western Gall Rust tinue to enlarge, year after year, resulting differs from most of the other rusts in large galls on the main branches and occurring on conifers. the trunk. The surfaces of young galls Control: Because direct infection from are covered with more or less run togeth­ pine to pine occurs, elimination of the er orange pustules ( aecia) . On older alternate hosts of the rust does not result galls the bark, together with the aecia, in control. Infected trees must be re­ sloughs off exposing the wood. A collar moved from the stand. All trees with of· dead bark remains at the top and galls should be removed for a distance bottom of the gall. of at least 1,000 feet around nurseries. The shape of the galls distinguishes Infected nursery stock should be de­ this rust from the other common blister stroyed immediately. On ornamental rusts on Lodgepole and Ponderosa Pine. trees, the individual galls can be removed These other blister rusts ( Cronartium by pruning.

PINE-Western White Pine Pinus monticola A TROPELLIS CANKER The following year, a second fruiting Atropellis pinicola structure ( aecia) is produced where Cankers occur on the limbs of young pycnia were formed the year before, and trees, but seldom on the main trunk. The additional pycnia are formed both above needles on branches girdled by the ·cank­ and below where the aecia are located. ers die, resulting in "flags" that are easily The cankers continue to enlarge and confused from a distance with those elongate year after year, producing pycnia caused by blister rust. The cankers are at the margins of the canker and aecia smooth, elongated, flattened depressions over the central area. Once the canker which remain covered by the bark. The girdles the branch on which it is located, wood under the canker is bluish black. upward elongation of the canker ceases The black fruiting bodies ( apothecia) and the end of the branch dies, resulting on the bark are very small, rarely measur­ in a condition known as "flagging". The ing more than Ys inch in diameter, and canker, however, continues to spread usually have a short central stalk. downward, eventually reaching the main trunk, girdling it, and killing the entire Control: No practical control mea­ top above that point. sures are known, except to remove and burn infected seedlings in nurseries. The pycnia are inconspicuous, but the orange-yellow aecia are readily apparent, BLISTER RUST particularly during May and June. Cronartium ribicola The bark in the central area of old Cankers are first apparent only as cankers becomes cracked and fissured and slight_ swellings on two- to five-year-old covered with resin. On such cankers, twigs. The .year after the initial swelling, aecial production is limited to the mar­ minute black fruiting structures ( pycnia) gins of the cankers. Rodents often eat appear in the bark on the swollen area. the cankered bark.

27 The rust attacks all five needle pines, hoses for the Blister Rust, particularly and has been reported in Washington on in the vicinity of Western White Pine Whitebark Pine (Pinus albicaulis) and nurseries, should not be abandoned. on introduced Eastern White Pine (Pinus- BROWN CRUMBLY ROT strobus) as well as on Western White F omes pinicola Pine. See the discussion of this decay on Control: In the Pacific Northwest a Grand Fir. more concerted effort has been made to control this disease than any other forest DASYSCYPHA CANKER tree disease. Control has consisted of Dasyscypha pini eradicating the alternate hosts, currants The perennial cankers are swollen and and gooseberries ( spp.) on West­ flat faced and the bark over the canker ern White Pine sites. To assure essentially is roughened and cracked. Excessive resin complete eradication of the Ribes and flow is often associated with the cankers. to keep the disease in check, it is neces­ They are usually found on the smaller sary to rework an area two or three branches which they eventually girdle. On rimes at approximately five-year intervals. larger branches the cankers persist, but Western White Pine trees showing do not girdle the branch. The disease is resistance to the rust have been found. most prevalent at high elevations, but is Progeny of these trees are being used in also encountered on poor sires at lower an extensive breeding program aimed at elevations. combining resistance and gocxl. timber The cup-shaped fruiting bodies ( apo­ qualities. rhecia) present on the face of the cankers On ornamental trees, cankers and in­ measure Ys to ~ inch in diameter and fected limbs and twigs should be cut off have a short stalk. The inner surface of as soon as they are found. All Ribes the cup is bright orange, while the out­ growing within at least Y2 mile of White side is brown and hairy. Pine nurseries must be eliminated. Control: Not practical. Damage 1s The antibiotic Actidione promises to slight. be a very effective control for Blister NEEDLE CAST1 Rust. Actidione is available in either Bifusella linearis concentrate or ready-to-use form. The Lophodermium nitens concentrate should be diluted to 15 0 The shiny, black fruiting bodies of the parts per million of active ingredient in fungus are found on needles three or No. 1 fuel oil or diesel oil and applied as more years old. Infected needles turn a spray to the trunk of infected trees yellowish and then brown and drop pre­ from ground level to a height of 3 or 4 maturely. feet. The trunk should be thoroughly wet, Control: Needle Cast of Western but the spray should not run off. Individ­ White Pine is by no means as serious a ual trees can be treated for a few cents disease as the needle casts of several each, and large scale experimental spray­ other conifers (e.g. Ponderosa Pine and ing in forest stands has proven economic­ Larch ) . No practical control measures ally feasible. are known. A single treatment not only eliminates 1 Recently a severe Needle Cast of \'V'estern White the infections present on the tree but Pine has been found in Idaho and probably occurs in also provides protection against new in­ Northeastern \'V'a shington. One-year-old needles are att<~;cked, become uniformly tan brown for their fections for at least two or three years. enttre length and fall during the late summer. The disease is c hara ~ t.eri s ti c al!y concentrated in the upper Just how long protection is provided is crown. The frutnng bodies form a line on the outer fa ce of the needle and are slightly darker brown than not known. the dead needles. The age of the needles attacked a ~d . the. bro~ n color of the fruiting bodies easily As promising as Actidione has proven di sttnguish this Needle Cast from the two disc ussed above. This disease. which is caused by a species to be, the elimination of the alternate of Hypodermella, is currently under investigation.

28 PITTED SAP ROT the symptoms have become sufficiently Polyporus abietinus developed to diagnose the disease as Pole · See the discussion of this decay on Blight there is no indication of recovery. Subalpine Fir. In a given stand, only a single tree or a POLE BLIGHT small group of trees shows symptoms at the start, but as these trees become severe­ Cause unknown ly affected and die, others in the stand As the name indicates, the disease at­ develop the typical symptoms. tacks trees of pole size, those 40 to 100 Control: None known. This disease is years old. The foliage becomes yellow and under intensive study by Forest Path­ thin as a result of needle drop. The ologists of the U.S. Forest Service who length of the leader is reduced, and the are attempting to determine both its needles are shorter than normal. Elongat­ cause and possible control. ed cankered areas appear on the bole of the tree. The face of the canker is RED RING ROT often flattened and there is usually a Fomes pini copious flow of resin. Trees are killed See the discussion of the decay on over a period of one to ten years. Once Douglas Fir.

PINE-Whitebark Pine Pinus albicaulis The diseases most frequently encount­ BROWN FELT BLIGHT ered on Whitebark Pine also occur on N eopeckia coulteri We5tern White Pine. The following are See the discussion of this disease on reported on Whitebark Pine. Subalpine Fir. BLISTER RUST NEEDLE CAST Cronartium ribicola Lophodermium nitens See the discussion of this disease on See the discussion of this disease on Western White Pine. Western White Pine. BROWN CRUMBLY ROT RED RING ROT Fomes pinicola Fomes pini See the discussion of this decay on See the discussion ot this decay on Grand Fir. Douglas Fir.

SPRUCE-Engelmann Spruce Picea engelmamzii BROOM RUST DWARF MISTLETOE Peridermium coloradense Arceuthobium campylopodum f. The brooms this rust produces on microcarpum spruce are similar to those caused by Mistletoe is of much less importance Needle Rust (Melampsorella caryophyl­ on Engelmann Spruce than on Douglas lacearum) on the true firs. Indeed. the Fir, Larch, and Ponderosa Pine. See the rust on spruce has been considered iden­ discussion of Dwarf Mistletoe on Doug tical with that on fir by some workers. las Fir. Control: Individual brooms· are per­ LEAF RUST ennial and usually eventually kill the Chrysomyxa wetrt4 branches involved. On ornamental trees The fruiting bodies ( telia) are found the brooms should be removed. No other on . the one-year-old needles. They are control measures are warranted. waxy, orange to orange-brown spots

29 which open by longitudinal slits. There of old rrees. The wood initially becomes is no alternate host and the other spore reddish, finally turning yellowish brown. stages usually occurring in the life cycle In the advanced stage, elongated pits of a rust are not known to occur. filled with white mycelium are present Control: Damage is usually slight. in the decayed roots. Diseased roots are Ornamental trees infected by the rust covered with resin. may be sprayed with wettable sulfur as a The fruiting bodies are found on the means of controlling the rust. ground near infected roots. The base of NEEDLE CAST the fruiting structure is a perennial stalk Lophodermium piceae which is connected with a decayed root. Short, black, shining fruiting bodies are The annual growths, which consist of produced on the needles. The fungus is numerous, thin, leaflike branches, are not a serious pathogen and does a min­ produced in a cluster measuring up to imum amount of damage. a foot in diameter. They are white to Control: Not necessary. cream in color and arise each year from the perennial stalk. SPARASSIS ROOT ROT Sparassis radicata C antral: Impractical in forest stands, The fungus develops yellowish-white except for the removal of infected trees mycelial fans under the bark of the roots during improvement cuttings. SPRUCE-Sitka Spruce Picea sitchensis BROOM RUST cubes. The broadly ellipsoid pockets are Peridermiztm coloradense sharply defined and the wood between See the discussion of this rust on the pockets is firm. Engelmann Spruce. The fruiting bodies are small incon­ BROWN CRUMBLY ROT spicuous mushrooms that develop only Fames pinicola on dead trees and logs. See the discussion of this decay on Control: Not practical under forest Grand Fir. conditions. BROWN ROOT A N D BUTT ROT BROWN CUBICAL POCKET ROT Fames anna sus T rametes serialis See the discussion of this decay on See the discussion of this decay on Western Hemlock. Douglas Fir. BROWN TRUNK ROT BROWN CUBICAL ROT Fames o fficinalis Polyporus sulphureus See the discussion of this decay on See the discussion of this decay on Western Larch. Western Hemlock. NEEDLE RUST BROWN POCKET ROT Chrysomyxa ledicola Lentinus kauffmanii The yellowish-orange fruiting bodies This rot is usually found in the root ( aecia) occur on the needles. Sometimes and butt area of Sitka Spruce, but it the infection is so severe that infected may also extend into the main trunk. trees have a yellowish appearance. The The rot is a typical brown pocket rot, alternate host for this rust is Labrador the discolored wood in the pockets in­ tea ( Ledum groenlandicum). itially being brownish. In the advanced Control: Not serious enough to war­ stage, the pockets are filled with a rant control measures under forest con­ brown crumbly mass that is broken into ditions.

30 PITTED SAP ROT See the discussion of this decay on Polyporus abietinus Douglas Fir. See the discussion of this decay on SHOESTRING ROOT ROT Subalpine Fir. Armillaria mellea RED BROWN BUTT ROT See the discussion of this decay on Polyporus schweinitzii Douglas Fir. See the discussion of this decay on WHITE ROOT ROT Douglas Fir. Poria subacida RED RING ROT See the discussion of this decay on Fomes pini Douglas Fir. WILLOW Salix spp. CANKER and, although they are very small at the V alsa boreella start, they later enlarge to disclose the V alsa nivea (including Cytospora powdery uredospores. Still later, dark nivea) brown to blackish, crust-like areas (the Valsa sordida (including Cyto­ telia) appear on the under surfaces of spora chrysosperma) the leaves which earlier bore the uredia. V alsa salicina (including Cyto­ Like many other rusts, the complete spora salicis) life cycle involves two different groups See the discussion of this disease on of hosts. The alternate hosts for the Golden Aspen. Willow Rust are firs (Abies spp.), larch (Larix spp.) , currants and gooseberries LEAF SPOTS ( Ribes spp.), and saxifrages ( Saxifraga Marssonina spp. spp.) . While attempts have been made Cylindrosporium salicinum to recognize several different rusts on Septogloeum salicis-fendlerianae Willow and to associate them with the Pseudopeziza salicis (including various groups of alternate hosts, there Gloeosporium salicis) is so much similarity that it seems best The leaf spots produced by these var­ to recognize bur a single species. ious fungi are difficult to distinguish Control: There is no practical control from one another without the aid of a of Willow Rust. Even the removal of microscope. See the discussion of Leaf all possible alternate hosts within a ra­ Spots on Red Alder. dius of several hundred yards will not POWDERY MILDEW prevent the development of rust on Wil­ Uncinula salicis low, since the uredospores produced on Although the mildew fungus on Wil­ Willow can survive the winter under the low is a different species from those bud scales and then reinfect this host found on other hosts, the symptoms and the next spring. control measures are the same. See the SHOESTRING ROOT ROT discussion of Powdery Mildew on Red Armillaria mellea Alder. See the discussion of this decay on RUST Douglas Fir. Melampsora epitea Sl LVER LEAF DISEASE The first fruiting bodies to appear are Stereum purpureum orange to golden yellow. These are the This disease is of no importance on uredia and are located on the under side forest trees, but may occasionally occur of the leaves. They are circular in outline on shade trees. The leaves take on a 31 silvery appearance. The fungus enters Cont1'ol: Not practical under forest through wounds, rots the heartwood and conditions. Raking and burning the then attacks the sapwood and the bark. leaves from infected trees in the autumn The fruiting bodies are thin, leathery will materially reduce the incidence of and somewhat shelf-like. They have a the disease. Two or three applications of smooth purplish under surface. They are BordeatDC mixture at two-week intervals, nor produced until after the tree dies. the first application being made at the Control: Protect trees from wounding time the buds open in the spring, will and remove and burn all branches show­ keep the disease in check. ing symproms. SOFT WHITE ROT WH ITE MOTTLED ROT Daedalea confragosa Polyporus squamosus The decay is indistincdy mottled, and A white mottled rot of the heartwood faint brown zone lines may be present. is produced. The sapwood may also be The annual conks are leathery, shelf-like, invaded. Infection apparently occurs and up to 6 inches wide. The upper sur­ through wounds, and the decay is usually face is gray ro brown, smooth, and con­ found associated with wounds. centrically zoned. The under surface has The annual fruiting bodies are large, irregularly elongate, coarse pores, which measuring up to 20 inches in width, and sometimes almost appear gill-like. have a short, thick, lateral stalk which Control: Not pracrical under forest is black at the base. The upper surface conditions. On ornamental rrees avoid is whitish yellow and covered with darker wounding and disinfect pruning wounds. scales. The pores on the lower surface TAR SPOT are large ( three to six per inch) and angular. Rhytisma salicinum Black, tar-like thickened spots are pro­ Co ntro l: Not practical on forest trees. duced on the upper leaf surfaces. The On ornamentals remove all the infected surface of the spot is smooth and shiny wood and paim with a wound-sealing early in the season, bur becomes dull paint. black and ridged in the fall as fruiting bodies are developed within the spot. WHITE TRUNK ROT These fruiting bodies mature the next Fames igniarius spring on the fallen leaves on the See the discussion of this decay on ground. Birch.

YEW-Pacific Yew T axus brevifolia NEEDLE BLIGHT brown. The upper surface of an infected needle is covered with minute black Sphaerulina taxi fruiting bodies (perithecia) of the fun­ The needles of the current season are gus. The infected needles are cast. killed. Infected needles become light Control: No control methods have green and finally grayish or reddish been devised.

32 KEY TO THE FRUITING BODIES OF FUNGI COMMONLY ASSOCIATED WITH DECAY The number in parentheses shows the page on which each fungus is discussed. A. Sporophores with pores on the lower or outer surface. B. No bracket formed, i.e. no sign of a free margin; sporo­ phore entirely flat on the substrate. C. Sporophores cream to yellow throughout ______Poria subacida (14) CC. Sporophores light to dark brown ------P.oria weirii ( 8) BB. Margin at least partially free from the substrate, forming a bracket or shelf, or a stalked sporophore. C. Sporophores perennial, as indicated by more than one layer of tubes being visible on cutting through the center of the sporophore. D. Inner substance of the sporophore pinkish or red- dish ______Fames roseus ( 11) Fames subroseus ( 25) DD. Inner substance not as above, of various other colors E. Inner substance white, or light colored, not ,. · darker than wocxl color. F. Growing only on living ash ( Fraxinus) ___ _Fames fraxinophilus ( 4) FF. Growing on conifers. G. Context white, bitter to the taste (like quinine) ______Fames officinalis ( 21) GG. ~ontext pallid to wood colored, not bitter H. Sporophore thick, bracket-like or · hoof shaped ______Fames pinicola ( 15) HH. Sporophore thin, often nearly flat on the substrate with only the margin free ______Fames annosus ( 18) EE. Inner substance yellowish brown or darker. F. Upper surface of the sporophore with a distinct crust that is harder than the interior. G. Sporophore hoof shaped, the tubes elongate and not arranged . in distinct layers; pore sur­ face grayish to brown and not discoloring

on wounding ______Fomes fomentarius ( 6) 7 GG. Sporophore typically bracket shaped, the rubes arranged in distinct layers; pore sur­ face white in fresh specimens, becoming brown on wounding ------~------Fames applanatus ( 9) FF. Upper surface without a distinct, harder out- er crust. G. On hardwoods ------Fames igniarius ( 7) GG. On conifers; sporophore usually forming a bracket. H. Pores angular to irregular ( daeda- loid) ------~------Fames pini ( 12) HH. Free margin often indistinct, or even lacking; pores uniform in shape, rounded, ·smaller in diameter ______Fames nigrolimitatus ( 14) CC. Sporophores annual, only one layer of rubes presenr. D. Upper surface a dark red-purple or blackish var- nished crust, harder than the conrexr ______Polyporus oregonensis ( 20) DD. Upper surface without a distinct crust, and col- ored otherwise. E. Context very thin ( 1 mm. or less) ; pore surface showing tints of purple ______Polypo·rus abietinus ( 17) EE. Conrexr thicker, pore surface nor purplish. F. Context yellowish brown or darker. G. Sporophore nor srtpnate; with a globose granular core in the context ______P olyporus dryophilm ( 24 ) GG. Sporophore stipirate; no granular core in the context. H. Sporophore soft when fresh, brittle when dry; context uniform throughout Polyporus schweinitzii ( 12 ) HH. Sporophore firm, never brittle; context composed of rwo rather distinct layers, an upper soft one and a lower, more firm one next to the rube layer ______Polyporus tomentosus and var. circinatus ( 13) FF. Context white to wood colored, bur nor darker. G. Margin of the sporophore incurved and pro­ jeering downward below the level of the pore surface; growing only on Birch ( Betula) ______P olyporus betulimts ( 6 ) GG. Margin of rhe sporophore nor as above; growing on other hosts. H. Pore surface bright sulphur yellow when fresh; upper surface sulphur yellow to orange yellow ______Polyporus sulplnt1'eus ( 18 ) HH. Sporophore not sulphur yellow ro orange yellow in color. I. Sporophore sripirate; stem black at the base, often lateral, pores large and angular ______Polypo1'tts squamosus ( 32 ) II. Sporophore not stipitate. J. On conifers. K. Upper surface of the sporophore white or whitish, essentially smooth ------Polyporus anceps ( 26 ) KK. Upper surface of the sporophore brown, wi rh appressed hairs ___ Trametes serial is ( 10 ) JJ. On hardwoods. K. Pores small and angular, but uni­ form in size and shape, averaging 4-5 per miLlimeter ------·- Polyponts spragttei ( 24 ) KK. Some pores irregular, daedaloid ro somewhat elongate, 0.5-l.Smm. in diameter or width ______D aedalea confragosa ( 32 )

34 AA. Sporophore without pores on the lower or outer surface; the lower surface may be smooth, or adorned with gills, teeth, etc., but not with pores. B. Lower surface of the sporophore with gills-mushrooms. C. Sporophore tough, edge of the gills saw like ______Lentinus kauffmanii ( 30) CC. Sporophore fleshy, edge of the gills even ______Armillaria mellea ( 13) BB. Lower or outer surface of the sporophore without gills. C. Lower surface adorned with grey-white coarse spines; context rusty-red ______Echinodontium tinctorium ( 19) CC. Not as above; lower surface of the sporophore smooth. D. Sporophores small, 1-4mm. in diameter, flat on the bark of living conifers with no free margin Aleurodiscus amorphus 14) DD. Sporophores not as above. E. Sporophores arising from the ground, consisting of numerous flat or fan-shaped, creamy, over- lapping branches ------Sparassis radicata ( 30) EE. Not as above, growing on wood. F. Growing only on coniferous wood; spore (low­ er) surface of fresh specimens becoming red- dish when bruised ______Stereum sanguinolentum ( 11) FF. Growing on hardwoods. G. Spore (lower) surface lilac, smoky purple to purple in color ------Stereum purpureum ( 31 ) GG. Spore (lower) surface gray in color ______Stereum ostrea ( 6)

35

Published and distributed in furtherance of the Acts of May 8 and June 30, 1914, by the Washington State University Extension Service, C. A. Svinth, Director, and the U.S. Department of Agriculture, cooper;~~2o