Bulletin STATE OF ILLINOIS DwiGHT H. Greex, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Frank G. Thompson-, Director DIVISION OF THE XATIRAL HISTORY SURVEY Theodore H. Prison, Chief Volume 21 BULLETIN Article 6 Preliminary Investigation of Oak Diseases in Illinois I. CEDRR CARTER PRINTED BV Al THORITY OF THE STATE OF ILLINOIS URBANA, ILLINOIS June 1941 STATE OF ILLINOIS DwiGHT H. Green, Governor DEPARTMENT OF REGISTRATION AND EDUCATION Frank G. Thompson, Director BOARD OF NATURAL RESOURCES AND CONSERVATION Frank G. Thompson, Chairman William Trelease, D.Sc, LL.D., Biology William A. Noves, Ph.D., LL.D., Chem.D. Ezra J. Kraus, Ph.D., D.Sc, Forestry D.Sc, Chemistry L. R. HowsoN, B.S.C.E., C.E., Engineering Edson S. Bastin, Ph.D., Geology Arthur Cutts Willard, D.Eng., LL.D., President of the University of Illinois NATURAL HISTORY SURVEY DIVISION Urbana, Illinois SCIENTIFIC AND TECHNICAL STAFF Theodore H. Frison, Ph.D., Chief Section of Economic Entomology W. P. Flint, B.S., Chief Entomologist C. C. CoMPTON, Ph.D., Associate Entomologist M. D. Farrar, Ph.D., Research Entomologist J. H. Bigger, B.S., Associate Entomologist S. C. Chandler, B.S., Southern Field Entomolo- gist L. H. Shropshire, M.S., Northern Field Ento- mologist W. E. McCaulev, M.S., Assistant Entomologist M. M. Petrakis, B.A., Entomological Assistant C. J. Weinman, Ph.D., Research Fellow in En- tomology H. B. Petty, B.A., Research Fellow in Ento- mology B. G. Berger, M.A., Research Fellow in Ento- mology T. F. WiNBURN, M.S., Associate Entomologist {U.S.B.E.P.^. and Commodity Credit Cor- poration, cooperating) Section of Insect Survey H. H. Ross, Ph.D., Systematic Entomologist Carl O. Mohr, Ph.D., Associate Entomologist, Artist B. D. Burks, Ph.D., Assistant Entomologist G. T. Riegel, M.S., Entomological Assistant K.ATHRYN M. Sommerman, M.S., Artist, Ento- mological Assistant Section of Forestry James E. Davis, M.F., Extension Forester Lee E. Yeager, Ph.D., Forester Section of Aquatic Biology D. H. Thompson, Ph.D., Zoologist George W. Bennett, Ph.D., Limnologist D. F. Hansen, Ph.D., Assistant Zoologist Bruno Limbach, B.S., Zoological Assistant Section of Game Research and Management Ralph E. Yeatter, Ph.D., Game Specialist Section of Wildlife Experimental Areas Arthur S. Hawkins, M.S., Game Technician F. C. Bellrose, Jr., B.S., Assistant Game\ Technician ' John M. Anderson, B.S., Junior Biologist Cooperative Wildlife Restoration Program (Slate Department of Conservation and U. S. Fish and Wildlife Service) Harry G. Anderson, M.A., Junior Biologist L. G. Brown, B.S., Junior Biologist R. E. Hesselschwerdt, B.A., Junior Biologist Section of Applied Botany and Plant Pathology L. R. Tehon, Ph.D., Botanist D. B. Creager, Ph.D., Research Pathologist J. C. Carter, Ph.D., Assistant Botanist G. H. BoEWE, M.S., Field Botanist Section of Publications James S. Ayars, B.S., Editor Consultant: Herpetology, Howard K. Gloyd, Ph.D., Director of the Museum, Chicago Academy of Sciences itribiUion from the Section of Applied Bota nrf Plant Pathology. (A42510—1600—3-41) CONTENTS Acknowledgments 195 Review of Literature .' 195 Methods of Study 198 Incidence of Oak Diseases 198 Canker and Dieback Diseases 200 Dothiorella Canker and Dieback 200 Coryneum Canker and Dieback 205 Cytospora Canker and Dieback 206 Xummularia Canker and Dieback 208 Diatrype Canker and Dieback 209 Phomopsis Canker and Dieback 211 Canker Diseases 212 Phoma Canker 212 Fusicoccum Canker 214 Sphaeropsis Canker 215 Bulgaria Canker 217 Dieback Diseases 217 Coniothyrium Dieback 217 Pyrenochaeta Dieback 218 Root Rot 219 Armillaria Root Rot 219 Miscellaneous Fungi 221 Cylindrosporium 221 RJiodoslicIa 222 Cephalosporium 223 Nigrospora 223 Ciinninghamella 224 Pestalolia 225 Chaelomium 225 Ahernaria --6 Penicillium --6 Summary 227 Literature Cited 227 rhe bur oak, Qiiercin inacrocdrpa Michx., is one of the several species of oak found in Illinois. Because native oaks are numerous throughout the state and have become increasingly popular, diseases of these trees are an important concern to Illinois citizens. ILLINOIS NATURAL HISTORY SURVEY BULLETIN VOL. 21, ART. 6 JUNE 1941 Preliminary Investigation of Oak Diseases in Illinois J. CEDRIC CARTER IN our investigation of tree diseases in Illinois the cases of disease of oak that have heen brought to our attention have increased each year since 1934. These cases have consisted mainly of canker and dieback diseases of small to large branches. Species of Gnomonia, Marssoiiiii, Ph\l- loslitt/i and Scptori/i, some of the fungi that cause leaf diseases, have been studied b\' other investigators, and control meas- ures have been recommended. Man\ heart-rot and a few root-rot fungi, name- ly, species of Aj-niillaria. Foiiies, Hyiliiiiin. Polyporus, Slereiini and Ozuiiiii/ii, have been studied by others in relation to their parasitism of oaks. Only a few twig-blight and twig- and branch-canker producing fungi, principally Cy/osponi chrysospiriiui (Pers. ) Fr., Diplodia longispora Cke. ik Ell., Nectrid cinnabtirina Fr., X. gnUitjeiid Bres., A', ditissima Tul. and Strumella coryneoidea Sacc. & Wint., have been in- vestigated by other workers. The diseases of oak studied by the author and the fungi associated with tlieni are described in this paper. ACKNOWLEDGMENTS The author wishes to express his sincere appreciation for the helpful assistance given to him during the course of this work. Through the cooperation of the Forest Preserve District of Cook County and many commercial nurseries in northern Illinois, he collected and studied many specimens of diseased oak material. Robert Everly of the Glencoe Park District, Glencoe, and George R. Pedlow of the Rockford Park District, Rockford, co- operated with the author in the study of the relationship of Ainiillaria inelha (\;ihl.) Quel, to the infection of oaks. Much credit is given to G. H. Boewe, Field Botanist of the Natural History Surve\ ; \Villiam Ellsworth Rose, \'illage Forester, Hinsdale; H. F. Seifert, Chief State Plant Inspector of Illinois, and his .issistants, William R. Jack, Glenn L. Pierce and John K. Karlovic ; and to many others for their help in collecting diseased oak material. The author is indebted to Dr. Lewis E. Wehmeyer, Associate Pro- fessor of Botany at the University of Michigan; Dr. E. F. Guba, Research Pro- fessor of Botany at Massachusetts State College; and Dr. H. A. Edson, Principal Pathologist in Charge, Mycology and Dis- ease Survey, U. S. Department of Agri- culture, and his associates—Dr. J. A. Stevenson and Dr. VV. W. Diehl—for the identification of several of the fungi de- scribed in this paper. The photographic illustrations were produced through the willing cooperation of Ray R. Hamm, photographer for the University of Illinois. Fhe examination of exsiccati was made possible by the Department of Botany, LTni\'ersity of Illinois. The author is in- debted to Dr. L. R. 'Fehon, Botanist and head of the Section of Applied Botany and Plant Pathology, Natural History Survey, under whose supervision the study was conducted, for suggestions and criticisms during the course of the work. REVIEW OF LITERATURE Internal disturbances of the living parts of oak trees have received very little atten- tion h\ investigators of tree diseases. The "alcoholic Hux" or white slime flux of oak was described by Ludwig (1886) and later reported by Massee (1907) at Kew. Ludwig ( 1888) also reported brown slime Hux of oak 1 years after he had described white slime flux. Slime flux of oak was further discussed b\' Tubeuf 5c Smith [195] 196 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 (1897), Holtz (1901), Ward (1901), Ogilvie (1924) and Cuba (1934). An abnormal discoloration of oak wood, called "brown oak," was described by Groom (1915). He associated Melanogaster va- riegatus Tul. var. broomianus Berk., a Penicilliutn-Wkt fungus, with the produc- tion of the disease. Davidson (1935) ob- served that FistuUiia hepatica (Huds.) Fr. was associated with the type of "brown oak" described by Groom. A recent in- vestigation by Cartwright (1937) estab- lished the relationship of F. hepatica to the production of "brown oak." A vascular disease of trees, none of them oak, was first reported by Hartley & Crandall (1935). This disease, since called wetwood, was later found in oak by Crandall, Hartley & Davidson (1937), who isolated bacteria from the wood adjacent to the wetwood regions. A bark disease of oak, called smooth patch, was described by Tehon & Jacks (1933). They found Aleurodiscus Oakesii (B. & C.) Cke. associated with smooth patch and believed it to be the cause of the disease. Craighead (1923) previously had attributed this type of injury to the larvae of Eiicyclops, and stated that these larvae have the peculiar habit of mining in the dry, corky outer bark of Quercus alba L. and other trees. Bark blotch of oak pro- duced by Dichaena quercina Fr. was de- scribed by Massee (1910). A trunk canker of Quercus rubra L. was described by Ludwig (1887) and attributed to Bulgaria inquinans (Pers.) Fr., considered by him a wound parasite. A basal canker of oak was reported on O. Cerris L., Q. palustris Muench. and Q. rubra by Hennings (1894), who found B. polymorpha (Oeder) Wett. associated with the disease and pointed out that this fungus may attack and kill the bark of old trees. A trunk canker of oak attributed to Polyporus hispidus (Bull.) Fr. was de- scribed by Sleeth & Bidwell (1937). Twig and branch cankers of oak have received some attention. Hartig (1894) attributed a Nectria canker in the cortical tissue of oak and other trees to Nectria ditissima Tul. Buckhout (1900) reported a disease originating in crotches of black oak {Quercus tinctoria Bart.) and pin oak ; he attributed it to N. ditissima. Zeller & Owens ( 1922) , Ashcroft (1934) and Clinton (1934) reported Nectria canker on oak and considered the disease to be produced by N. galligena Bres. Welch (1934a) reported Nectria canker, as caused by A', ditissima, on oak in Con- necticut, Massachusetts, New Hampshire and Vermont. Kienholz & Bidwell (1938) listed Nectria canker on black, chestnut, red, scarlet, scrub and white oaks in Connecticut and stated it was caused by Nectria coccinea (Pers.) Fr. and other Nectria species. Welch (1934b) and Spaulding, Grant & Ayers (1936) pointed out that no hardwoods are immune to attack by Nectria. Grant & Spaulding (1939) recently pointed out that the ave- nues of entrance for the canker-forming species of Nectria on oak and other hard- woods in New England are branch stubs, cracks at the axils of branches, and rub- bing injuries, as well as other avenues of infection not determined. Strumella canker on oak, with which Strumella coryiteoidea Sacc. & Wint. is associated, was found by Anderson (1922) in Illinois in 1919. Strumella canker was also reported on oak by Bidwell & Bram- ble (1934), Bramble (1934), Clinton (1934), Davis (1935), McKenzie (1937), Kienholz & Bidwell (1938) and others (Anonymous 1934). Heald (1914) and Heald & Studhalter (1914) pointed out that there are two forms of Strumella infection. One form produces cankers and the second form causes a diffused type of infection. In this latter type of infection the fungus spreads rapid- ly in the tree without callus production, and the tree dies quickly. Cytospora chry- sosperma (Pers.) Fr., the willow canker fungus, was reported by McKenzie (1937) to be the cause of a canker on oak. Two years earlier, Cytospora sp. (Hum- phrey & Wood 1935) was reported to be the cause of canker on oak in New Jersey. A canker on oak described by Hartig (1894) was attributed by him and by Henry ( 1902) to Aglaospora taleola Tul., considered Diaporthe taleola (Fr.) Sacc. by Massee (1910) and by Moreillon (1918). Moreillon pointed out that, in Switzerland, twigs up to one-half inch in diameter and 20 inches long were affected with D. taleola. A nut rot of red oak was attributed by Orton ( 1908) to "Sphaerop- sis quercina" Cke. & Harkn. Twig blight and canker of chestnut oak, Quercus Prinus L., is becoming in- June 1941 CARTER: OAK DISEASES IN ILLINOIS 197 creasingly important. The hlight, found occasionally on O. alba as well as on O. Priiiiis, was reported in 1912 and de- scribed in 1014 by Ingram (1012, 1014), who demonstrated that Diplndia loiiyi- spora Cke. & Ell. is the fungus responsible for the disease. Ingram (1914) stated that infection occurs through wounds in the bark and that the fungus, after pene- trating the twig, does not extend into the leaves. Small trees are killed outright; large trees are weakened by loss of \()ung branches and die later. This twig blight was reported on O. Prinus and other species of oak bv Haensler (1932), Clin- to-i (1034), Davis (1035) and White (1936). In 1035 it was found on C^- "lb" in California, Maryland, Texas and Wis- I consin (Edson & Wood 1936). Four years later, it was reported on Quercus , in Iowa, Massachusetts, Virginia and j West Virginia by Waterman (1939). A similar twig blight has been attributed to Splititropsis iiudoriini Berk, bv Rankin (1014) and others ( Anonvmous 1030, 1031). ' Brjtr\(jdiplijdia RoveneUii Sacc. was found by Babcock (1015, 1016) to be the cause of twig blight on scarlet oak in the vicinity of Cincinnati, Ohio, and to attack the host through bark wounds. Doihidea uoxia Ruhl. was reported on oak by Ruhland (1904). He stated that it attacked the living cortex of twigs and branches of oaks, and that it was especially noticeable in \oung trees. The conidial stage of this fungus he called Fusicociurn noxiu/ii Ruhl. D. noxia has since been reported on American oaks in Europe by Bavendamm (1036). A tumor disease of oaks and hickories in the United States, attributed to a species of Plioriiopsis. was described by Brown ( 1038). Other fungi, that are mentioned by Boyce (1038) and that appear to be related to canker diseases of oak, are Stereuni riigosuni Pers. and Foines igniarius ( L. ) Gill in Germany and / . rubustus Karst. in France. Ten genera of fungi were reported b\- Carter (1038) associated with branch dis- eases of oak: Bulc/ariti, Coryneum, Cyto- spora, Diatrype, Phoiiia. Phumachura* Rhodusticta, Spaeropsis and VstuliiiuA From diseased specimens of oak Carter isolated the fungi Alternaria, Armillaria, (Jnryncui/i, Cylnspora. I usarium, Peni- rillium, Phoma, Phomachnra* Plinmop- sis and VstiilinaA Other genera of fungi that are believed to cause twig and branch diseases of oak include Pseudovalsa and Coryiieum. Pseu- dnvalsa longipes (Tul.) Sacc. was report- ed on oak by Henry (1902). Wehmeyer (1926) reported P. longipes on twigs of Q. coccinea Muench. and studied the cul- tural life history of this fungus and its imperfect stage, Coryiieuiii Kunzei Corda. P. sigmolded (Cke. & Ell.) Sacc, which Wehmeyer believed to be synonymous with P. longipes, and an unidentified spe- cies of Coryneuin were reported in Fort W^jrth, Texas, by Taubenhaus & Ezekiel (1932), who suggested that the Coryne- iim. which was causing injury to live oak, might be a stage of P. sigmoidea; they found both forms fruiting on the same diseased tree. A stem blight of Q. vir- giniana Mill, in Texas was first reported in 1934 and attributed to Trubulia ery- ihrosporii ( B. i!i C.) Cke. by Taubenhaus (1934, 1035). Death of three pin oaks and one willow-leaf oak on the Kansas State College campus in 1033 and 1034 was associated with Diatrype stigma (Hoffm.) Fr. b\ Lefeb\ re & Johnston (1035). Atkinson (1807) had previous- ly reported the same fungus on dead oak branches at Auburn, Alabama. Godroni- opsis Quernea (Schw. ) Diehl 5c Cash was reported by Overholts (1034) on living branches of Q. coccinea. fistulina hepa- tica (Huds.) Fr. was found by Hartig (1804) to be the cause of a reddish-brown wood rot of oak and was suggested by Braid (1024) as a major factor in the production of staghead and hollow tree of oak. Weir (1025) reported that Endo- thiii gyrosa (Schw.) Fr. was capable of causing a root disease of Q. velutin/i Lam. Numerous studies have been made on the relationship of .Irmillaria mellea (\ ahl.) Quel, to the decline and death of oaks and other trees. Thomas ( 1934) reported that the fungus is capable of in- \ ading the roots through the sound and health)' periderm by a combination of mechanical and chemical means. Camp- bell (1034) maintained that the black zone lines produced in the infected roots b>' this fungus are actually sheets or plates of black strands, which he called pseudo- sclerotia. Rhizomorphs of A. mellea are 198 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 present and often widespread in soils cov- ered by natural oak stands. Numerous control measures have been suggested and recommended, but none of these has proved to be completely satisfactory (Home 1914, 1915, 1919, Newman 1926, Rankin 1927, Brooks 1928, Owens 1928, Hubert 1931, Kendall 1931, Felt & Ran- kin 1932, Heald 1937 and lioyce 1938). The parasitic nature of most of the above fungi has not been proved. A large majority of these fungi, which have been reported on living oak trees, have been associated with cankers on twigs and branches. These twig and branch cankers, in the later stages of their development, frequently result in twig blight or branch dieback. METHODS OF STUDY To study the parasitism of various fungi that might be associated with the diseases of living oaks it was necessary to examine many diseased specimens. Culture tests were made in order to isolate the organism that was present in the diseased tissue of each specimen. Wood pieces for culture tests were taken from diseased living tissue and from diseased dead tissue that had been only recently killed, and isolations were made of those fungi that were sporu- lating on the dead tissue. The fungi present in the diseased speci- mens were isolated in the following man- ner. A diseased specimen, including the bark, was sterilized in 0.1 per cent mer- curic chloride for 1 to 2 minutes, and then thoroughly rinsed in sterile water. After the bark was removed, several slices were cut from the diseased wood with a sterile scalpel. With sterile forceps some of the slices were planted directly on Difco corn meal agar in Petri dishes. The others were sterilized individually by be- ing dipped in and out of a 0.1 per cent mercuric chloride solution. Then they were washed in two changes of sterile water and planted on the agar in the Petri dish with the unsterilized slices. A similar procedure was followed in making isola- tions from diseased bark. Single-spore plantings were made of the fungi found fruiting in the cankerous tis- sue. These plantings were made by steril- izing the cankerous tissue, which contained the fungus, in 0.1 per cent mercuric chlo- ride for 30 to 60 seconds. The fruiting structures were then removed with a sterile scalpel and placed in a large drop of sterile water on a flamed microscope slide. The fruiting structures were crushed, placed in suspension and agitated to liberate the spores. A sterilized bac- teriological loop was used to transfer the spores in suspension to agar in Petri dishes. The spores were planted in streaks across the agar. Widely separated spores on the agar, that were visible with the low power of the microscope, could be located and their positions marked. After the spores had started to germinate they were easily removed, with a small amount of the sur- rounding agar. A sterilized, bacteriologi- cal, spatula-tipped wire was used to remove these germinating spores, and they were placed on sterile agar in Petri dishes for further development. Some histological studies were made of the diseased tissues. Some of the fungi associated with canker and with dieback grew and progressed slowly in the host tissues. It is quite possible that other fungi of secondar\' importance were present in these diseased tissues. In such cases histo- logical studies would be of very little value. Careful examinations were made of living xylem from which Dothiorella and Coryneum had been isolated. Cart- wright's (1929) method of staining fungal mycelium in wood sections was followed in this investigation. INCIDENCE OF OAK DISEASES Diseases of oaks and other trees have not received so much attention and con- sideration as have the diseases of field crops, vegetables, fruits and similar eco- nomic plants. However, in recent years the importance of tree diseases has been forcefully brought to our attention by the destruction of the American chestnut and by the widespread dying of the American elm. The destruction of trees by disease is an economic and aesthetic loss to the inhabitants of large areas of the United States. Because native oak forests and groves are numerous throughout Illinois, and because oaks for shade and ornamental purposes are receiving more attention than formerly from nurser\men and home own- ers, diseases of oaks are now an important concern to the people of the state. Vol. 21, Art. 6 CARTER: OAK DISEASES IN ILLINOIS 199 In this investigation, diseased trees were found among native, shade, ornamental and nursery phmtings of oaic, including Quercus alha L. (white oak), O. bicolor Willd. (swamp white oak), Q. borealis maxima Ashe (red oak), O. ellipsoidalis E. J. Hill (Hill's oak),~Q. imbricaria Michx. (shingle oak), Q. tnacrocarpa Michx. (bur oak), O. marilatidica Muench. (black jack oak), Q. Muhlen- bergii Engelm. (chinquapin oak), Q. pa- lustris Muench. (pin oak), O. stellaia Wang, (post oak) and Q. veliilina Lam. (black oak). Future reference to these oak species will be made by common name. The diseases considered in this investiga- tion are those of the twigs, branches and to some extent the trunks of living trees. The much-studied heart rots and leaf dis- eases, as well as the root diseases, have received very little attention in the present study. However, it has been necessary to give some consideration to shoestring root rot caused b\' Armillarin mellen (Vahl.) Quel. The diseases most frequentlv observed on the wood of living oak trees in Illinois are known as cankers, dieback and stag- head. Although wilts of elm and maple are common, wilt of oak is very unusual. On oaks, the development of cankers as well as the progress of dieback and staghead is very slow. The slow progress of these diseases, which each year spread only a few inches in some cases to a few feet in others, is ideal for the growth and fructifi- cation of parasitic fungi. Furthermore, saprophytic fungi may attack and develop on and in the dead and dying tree parts. It is not uncommon to find that the same fungus is associated constantly with the perennial development of a canker or dieback on an oak branch. The frequency and consistency with which numerous fungi have been associated with the dis- eases of oaks leave no doubt of their im- portance in the occurrence, prevalence and spread of the diseases. The diseases under consideration in this bulletin occur as cankers, dieback and root rot. Cankers are found on twigs and branches of trees of various sizes and on trunks, principally, of small trees. Die- back is found on twigs and branches. I Deep wood infections, associated with both canker and dieback diseases, are found mainly on medium to large branches. The blighting of leaves and twigs, which usu- ally results in twig cankers or dieback, is quite prevalent throughout the state. Often, differentiation between cankers and dieback is difficult because many cankers continue to grow and spread year after year, and frequently branches are entirely encircled by them. After a canker has encircled a branch, subsequent dying may develop as dieback, as in Dothiorella can- ker and dieback. In some cases, when the twig is afifected with dieback, the whole twig is killed, and the causal agent con- tinues to grow and to spread into the branch at the base of the twig. From this type of infection a branch canker may de- velop with the dead twig for the original region of infection, fig. 27. Differentia- tion between canker and dieback seems to depend more on the physical appearance of the diseased region than on the infec- tious agent. In the study of diseased specimens ob- tained for examination, an attempt was made to associate specific symptoms with a specific fungous parasite. Accomplish- ment of this purpose was impracticable, because each of several fungi was associ- ated with cankers, dieback and twig blight. The external and internal characters of several cankers may appear to be identical, but the causal organisms associated with these cankers may represent several species of fungi. This situation holds true for dieback and twig blight, as well as for cankers, and makes practically impossible an accurate field diagnosis of the cause of a given branch disease of oak. Twelve genera of fungi were found fruiting on the cankerous tissues of 80 of the diseased oak specimens that were studied. These genera and the number of specimens infected by each genus are given in table 1. Of the fungi observed fruiting on the 80 specimens, Dothiorella and Coryjieum were prevalent, as shown in table 1. Dothiorella comprised 42.50 per cent and Coryiieum 21.25 per cent of the specimens. Ten genera, namely, Cytospora, Phoma. Diatrype, X/immiilaria, Fusicoceum , Bul- garia, Cylindrosporium, Phomopsis. Rho- dostiita and Sphaeropsis, comprised the re- maining 36.25 per cent. A list of the genera of fungi obtained in culture from 284 specimens of diseased oak and the frequency of the appearance 200 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 of each genus may be observed in table 2. Although Dothiorellii was secured in the fruiting stage from only 6 specimens, a fungus which appeared similar to single- spore cultures of Dothiorella but which did Table 1.—Genera of fungi found fruiting in the cankerous oak tissues of 80 specimens. Genus June 1Q41 CARTER: OAK DISEASES IN ILLINOIS 201 li\ing tissue from 1 to 10 inches beyond the lower extremity of the cankerous re- gion. The streaks of discoloration in the xylem vary in size. Some streaks are so small as to be just visible, while others are approximately 2 mm. in diameter. In some cases the streaks coalesce and form solid regional discolorations. Dothiorella was associated with branch cankers and dieback of 40 diseased speci- mens collected throughout Illinois from black, pin, red and white oaks. Indica- tions are that the growth of the fungus is perennial : the cankers continue to progress in their de\elopment for several years. Branches that show dieback continue to die \ear after year until the whole branch is killed. In many instances infection occurs first on twigs and small branches. These infections spread and invoh e the larger branches when the originalh infected part has been killed. The pycnidia of Dolhwrella var\ in their development from single pycnidia to aggregated p\cnidia in a pulvinate stroma. In fig. 4, pycnidial chambers are shown in the vertical section of a stroma. The fruit- ing structures are laid down in the phel- logen-phelloderm tissues of the branch, and their development causes a separation of these tissues accompanied by very little cellular disintegration. Further develop- ment to maturity ruptures the overlying phellem and epidermis. These tissues are forced back to form oval to round open- ings with shielded sides. The erumpent stromata are visible through these open- ings, as shown in fig. 2. Mature stromata of Dothiorella in the cankerous bark are dark brown to black, sessile, dothideoid, erumpent, 600-1300 IX in diameter and 400-500 /i high. The pycnidial walls for the most part fuse to form the stromatic tissue. The pycnidial cavities are globose to o\oid, 145-300 /x in diameter, and open by individual, cir- cular ostioles 15-30 fj. in diameter. Co- nidiophores are hyaline, simple, 6—15 X 2.8—3.4 ju,, and papillate. The conidia, shown in fig. 5, are continuous, hyaline, 15-26 X 9-15 jx, and ovoid. The content of each spore is granular. A culture of Dothiorella, grown from a single-spore isolation on corn meal agar, is shown in fig. 6. The fungus produces an exceedingly sparse mycelial growth with gray aerial hyphae, gray to very light tan surface hyphae and gra\"-black to tan sub- surface hyphae. A single germ tube from Fig. 1.— Dothiorella canker and dieback on pin oak. The smooth, sunken, brown to almost black, diseased region, shown at the lett of the branch, contains numerous black, erumpent stromata of Dothiorella. X Ja. 202 ILLINOIS NATURAL HISTORY SURVEY BULLETIN \'(jl. 21, Alt. 6 each spore pushes out as an evagination of Spore germination as high as 66 per cent the spore cell wall, and the cell contents occurs in approximately 10 hours. This pass from the spore into the germ tube. high germination percentage is obtained Fig. 2.— Dothiorella dieback on red oak. The brown to black, cankerous bark ot each branch contains numerous black, erumpent stromata of Dolhiorelta. X 2. Fig. 3.—Wood discoloration of white oak associated with Dothiorella infection. Discoloration of the xylem tissue is characterized by fine to broad streaks that frequently coalesce and appear as solid regional discolorations. X 1^. June 1041 CARTER: OAK DISEASES IN ILLINOIS 203 wlu'ii the spores are suspended in sterile, distilled water on a microscope slide and when the slide is maintained in a moist atmosphere. Single-spore colonies on corn meal agar produce an average diameter growth of 46 mm. in 8 days, or an average Do/hiorellfi was isolated from ti\e dis- eased oak specimens affected with twig blight. Two of the five isolations were ob- tained from black oak: one from discolored li\ing wood of a twig and one from a blighted petiole. Three were obtained Fig. 4.- .A stroma of Dolhiorella. The black stromatic tissue and pycnidial cavities that contain spores are shown in vertical section. X ,S0. J Fig. 5.—Spores of Dolhiorella. I'he spores .irc continuous, hyaline and ovoid. X 300. daily diameter growth of 5.8 mm. Germ tubes reach a length of approximately 188 /I before any branching occurs. Cultures of Dotliiorella grown from ^iIlgle-spore isolations failed to produce fructifications on artificial media or on sterilized wood of white oak. However, fructifications of Dolhiorella developed on the naturally infected wood pieces that w ere placed on corn meal agar. Fig. 6.—Culture of Dolhiorella. On corn meal agar, this fungus produced gray to tan mycelium without stromata. from pin oak: two from blighted petioles of two separate specimens and one from a twig. In the above cultures the fructifica- tions varied from a pycnidium with one chamber to compound p\cnidia in a stroma. The fructifications are black, ovoid, ostio- late, pseudoparenchymatous, and 260-530 /I in diameter. They contain conidia that are 18-25 X 12-17 fx, hyaline, ovoid and continuous. The conidiophores are hya- line, 12-16 X 2.8-3.4 jx, papillate and un- hranched. Microscopic examination did not reveal the presence of fungous hyphae in the dis- colored regions of the x\ lem, fig. 3. Many of the trachea and parenchyma cells ap- peared to be partially filled with a granular material, and many of the cell walls were dark and evidently were not stained. The Dolhiorella described in this paper was previously called Phoinaehora by Car- ter (1938). Our material agrees with Dolhiorella querciria (Cke. & Ell.) Sacc. as represented in Shear's New \'ork Fungi No. 373. Other fungous cultures from 135 speci- mens of diseased oak appeared to be iden- tical with Dolhiorella in every respect ex- 204 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 cept that the\' did not fructify on artificial media, on sterilized oak twigs or on ster- ilized clover stems. They were isolated from 10 species of oak, nameh, black, black jack, bur, chinquapin, pin, post, red, shingle, swamp white and white. They were grown from bark and wood of can- kers, some with and some without Dotliio- rella stromata in the bark, from dieback specimens, from blighted petioles and twigs, and from deep wood infections. The deep wood infections were conspicu- ous because they showed dark brown to black discolored regions, illustrated in fig. 3. Over 50 per cent of the fungi cultured from the deep wood infections were sim- ilar in appearance to Dothiorella. How- ever, it cannot be conclusively stated that these cultures were Dothiorella, since fructifications did not occur. Inoculation Trials.—On March 8, 1937, three white oaks, grown in flower pots in the laboratory, were inoculated with living cultures of Dothiorella. The method of inoculation was, in general, that described by Carter (1936) in the inocula- tion of American elms with Cytosporina ludibunda Sacc. By March 20, 1937, leader tips of two of the three inoculated trees had started to die. By April 23 each of the two dying trees had 3 inches of its leader tip dead. The third tree showed dying back of the leader tip by May 1. All three trees were dead by July 1, 1937; however, at that time no stromata of Dothiorella had de- veloped in the dead bark. Stromata were first observed in the dead bark of one of the above three trees on March 24, 1938, when attempts were made to reisolate Dothiorella from each of the three trees. These stromata were brown to black, globose to ovoid, pseudo- parenchymatous, dothideoid, 600-800 /n in diameter and 450-530 jx high. They con- tained from one to several pycnidia, and the pycnidial walls, for the most part, formed the stromatic tissue. The pycnidia were immature, and conidia developed in only a few pycnidia. These conidia were hyaline, 18-23 X 12-16 ;u,, ovoid, contin- uous, and had granular contents. Dothiorella was reisolated in pure cul- ture from each of the three inoculated oaks. The reisolated Dothiorella did not produce stromata on artificial media. However, it did produce stromata on ster- ile white oak wood and on sterile clover stems. The oak wood and clover stems were partially submerged in corn meal agar in test tubes. Approximately 6 months were required for the stromata to develop. These stromata were ovoid, black, osti- olate, pseudoparenchymatous, and 775- 825 X 625-675 /i. The pycnidial cavities were 350-670 jx in diameter, and the conidia were ovoid, hyaline, 18-22 X 12- 16 fi, continuous, and had granular con- tents. The reisolated Dothiorella was identical in appearance with the original isolate. A second series of inoculations, previ- ously reported by Carter (1940), was ' made, June 20, 1940, on nine oaks (three each of black, red and white oaks) located in the experimental nursery of the Natural History Survey. Dothiorella infection of these trees occurred, and within 3 weeks after the trees were inoculated bark was dying around the inoculated regions. Can- ker and dieback developed with external and internal symptoms identical to those described above as the characteristic symp- toms of Dothiorella canker and dieback. Stromata of Dothiorella appeared in the infected bark within 7 weeks after inocu- lation but had not become erumpent by the end of 9 weeks. Dothiorella was reisolated in pure cul- ture from representative trees of each of the three species of oak on August 17, 1940. The reisolated Dothiorella was identical with the original isolate. Adequate check trees were maintained for both the 1937 and the 1940 series of Dothiorella inoculations. In no instance was Dothiorella cultured from the check trees. Coryneum Canker and Dieback Coryneum cankers develop on twigs and small to large branches of oaks of various sizes, and occasionally on trunks of small oak trees. They are found most frequently on small branches. The diseased tissues of Coryneum canker and dieback are red- dish brown ; the cankerous region is some- what sunken and is dotted with erumpent acervuli of the fungus, as may be seen in fig. 7. The borders of the canker are sharply defined by the contrast in color of the healthy and diseased tissue and by the shrinking of the cankerous bark. Inter- June 1941 CARTER: OAK DISEASES IN ILLINOIS 205 Fig. 7.--Cor\neum canker and dieback on red oak. The section of a diseased branch pictured here shows black, erumpent acervuli in the reddish-brown, shrunken bark. X^s- Fig. 8.- Portion ot' an acervulus of Coryrie- 11)11. Several attached spores and the broken host tissue are shown on the upper portion ot' the acervulus. X 100. iKilly tile cankerous tissue is light brown, and the discoloration in the xylem does nut progress over 2 cm. beyond the ex- ttrnal cankered region. From observa- tiiiii it seems quite evident that Cnryrieum liriiws \ear after year and that the cankers progress down the branch. Not infre- quently a canker encircles a branch and de\ elops into dieback, which may progress to the base of the branch. In a few cases Coryneiii/i was associated with twig blight. Coryneum canker and dieback was found on pin, red and white oaks. The fungus (Ifiryiieum was grown from cankerous bark, discolored wood, blighted twigs and li\ ing wood adjacent to developing cankers un post, shingle, red, swamp \\hite and white oaks. The acervulus of Coryneuin is laid down fundamentally in the phellogen-phelloderm region of the bark. Development of a compactly interwoven hyphal mass, the base of the acervulus, causes a separation uf the associated tissues that is accom- panied by very little cellular disintegration. Further development of the acervulus, especially about the time conidia are pro- Fig. 9.— Spores of Coryneum. Each tip cell and base cell of the tan to olive-brown, curved spores are hyaline. X 230. duced, ruptures the overlying phellem, epidermis and cuticle, forcing these tissues back ; the result is a more or less triangular opening through which the black acervulus is visible. A portion of an acervulus in vertical section, with attached conidia, is shown in tig. 8. The erumpent acervuli are dark brown to black, discoid or pulvinate, compact, 1000-1500 /i in diameter and 260—100 /I. high. Conidia are shown in fig. 9. They are 3- to 6-septate, not constricted at septa; they are curved, clavate or nar- row-fusiform, tan to olive brown, 40-80 X 9—18 yu, with each tip and base cf'l hyaline. The conidiophores are 15-30 X 3—1 fjL, straight to slightly curved, hyalini' to brown and few-septate. Single spores of Coryiieu/ii planted on 206 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 corn meal agar give rise to slowly spread- ing, dense mycelial growth. A culture of Coryneiim is illustrated in fig. 10. The surface and aerial growth is hluish gray with a margin, approximately 1 mm. wide, of white hyphae. The subsurface growth as greenish gray. Sporodochialike, grayish- brown acervuli arise promiscuously over the surface of the older portions of the Fig. 10.— Culture of Coryyieiim. The fungus grows slowly and produces gray to tan myce- lium on corn meal agar. Acervuli and spores develop on old cultures when the agar becomes dry. culture. Typical tan to olivaceous-brown conidia arise from the acervuli and are interspersed with aerial hyphae. Growth of colonies from single-spore plantings in- creased radially about 1.6 mm. each day for a period of 28 days. In culture the acervuli are 1200-1600 /x longitudinally and 650—675 jx vertically, and the conidia are 40-90 X 12-19 jx. In shape and color, acervuli and conidia that developed in cul- ture are similar to those that developed on the branch. Coryneum has not only been grown in culture from single-spore trans- plants but it also has been isolated from cankerous bark and from discolored living sapwood beyond the diseased tissue of cankers. The identification of this fungus as Cor- yneiim Kunzei Corda (Wehmeyer 1926) was verified by Dr. Lewis E. Wehmeyer. Microscopic examination of branches of red oak infected with Coryneum showed no evidence of the fungus in the xylem tissue. Inoculation Trials.—Three white oaks were inoculated with Coryneuni on March 8, 1937. The procedure followed is that described on page 204 for the Dothiorella inoculation trials. Two of the three trees showed dying of the leader tips by March 20. A gradual dying back of these two trees progressed rapidly from tip to base, and by April 1 they were dead. Culture tests were not made from these trees until March 24, 1938. Coryneuni acervuli did not develop in the bark of the dead trees during the period from April 1, 1937, to March 24, 1938, and no fungus was obtained in cul- ture tests from these two trees. The third tree inoculated with Coryneuni showed no signs of infection by February 1, 1939. Adequate check trees were maintained for this series of Coryneuni inoculations. In no instances was Coryneuni cultured from the check trees. Cytospora Canker and Dieback Cytospora canker and dieback was found on red oaks in the northeastern section of Illinois. Isolations of Cytospora were ob- tained from cankerous bark, diseased wood, blighted petioles and twigs, and discolored living wood adjacent to developing cankers on black, pin, red and white oaks. Cyto- spora canker and dieback on a black oak branch is shown in fig. 11. The cankerous tissue is sunken and varies from light to dark brown ; few to many scattered erum- pent stromata appear in the bark. The stromata appear as small, circular, black spots. Stromatic regions appear oval to elongate when two or more stromata fuse. Shrinkage of the cankerous tissue causes the irregular margin of the canker to ap- pear raised. Internally the diseased xylem is light brown above and below the base of the canker ; the woody tissue beneath the cankerous bark is discolored and varies from dark brown to almost black. The fungus develops year after year, and the cankers continue to spread down the in- fected branches. A gradual drying out and dieback of the branches result when they are completely girdled by the cankers. The stromata are laid down in the cor- tex just beneath the phelloderm. As the interwoven hyphal mass continues to de- velop, the outer cortical cells disintegrate, the stromata develop laterally, and the June 1941 CARTER: OAK DISEASES IN ILLINOIS 207 periderm and epidermis are ruptured by the time the conidia are mature. An erumpent stroma is shown in vertical sec- tion in fig. 12. Stromata are black, val- soid, tubercular, pulvinate, compact, 550- 2000 ,, in diameter and 400-600 /j, high, Fig. 12.—Portion of a stroma o( Cylospora. The erumpent appearance of the stroma is shown in vertical section. The black stromatic tissue with its locules and spores is embedded in the cankerous host tissue. X 5.S. \^ d Fig. 11.— Cytospora canker and dieback on black oak. Only a few scattered, erumptnt stromata are present in the light to dark brown, sunken, diseased region. The border ot this region is made conspicuous by the contrast in color of the living and diseased bark and by the shrunken appearance of the diseased bark. X 1. Fig. 13.—Culture of Cylospora on corn meal agar. The black stromata are embedded in white to greenish-white tutts ot hyphae. and they are exposed through the ruptured host tissues. The locules are irregularly arranged. The conidia are continuous, hyaline, allantoid, elongate, 4.5-9 X 1 — ^ fjL, and they exude from the stromata in cirrhi. Conidiophores are typically simple but occasionally are branched. A culture of Cytospora, grown on corn meal agar, is shown in fig. 13. The fungus, in its early development, appears white 208 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 with a very sparse growth of interwoven mycelium. Later a more dense growth of white surface and aerial mycelium de- velops. Tufts of hyphae appear more or less concentrically or promiscuously inter- spersed with the mycelium. They are white to greenish white above and green below. In some instances the hyphae adjacent to the developing tufts are liglit brown. The stromata are black, firm, multilocular, tu- bercular, 525-1600 /i in diameter, 600- 1500 /JL high and embedded in tufts of hyphae. The conidia produced in culture are 3-9 X 1-3.5 /x. Except for greater variability in size, they are identical with the conidia produced in the host tissue. The conidiophores are simple to branched, 10-15 X 2-3.5 /x, and hyaline. This fungus is considered to be Cyto- spora intermedia Sacc. ( I'aha intermedia Nits.). The pycnidial stage is identical morphologically with that of Jaap's Fungi Selecti No. 621 J'alsa intermedia Nits. (Cytospora intermedia Sacc). Nummularia Canker and Dieback Small to large Nummularia cankers were found on branches of red oaks. The cankers extend a few inches to several feet along the branches ; dieback results when the branches are completely girdled by the cankers. The cankers appear as sunken diseased regions with small to large stromata located at irregular intervals. The smooth, reddish-brown, cankerous bark and two stromata in a portion of a canker are shown in fig. 14. On old branches the bark turns black and becomes fissured. The fissures are produced by lengthwise and crosswise splitting of the bark. The borders of the cankers are sharply defined on young branches by a contrast in color between living and can- kerous tissues. There is no discolored streaking in the wood ; however, the wood appears dried out and light brown. Summularia stromata produced in the cankerous tissue are shown in fig. 14. These stromata are discoid to linear, sub- effuse and rather thick. Immature stro- mata are covered with a pulverulent, cine- reous, conidia! hymenium that sloughs off at maturity, when the stromata become black, carbonous, rigid, bare and usually somewhat convex. They are laid down in the phellem immediately under the epi- dermis, and the epidermis disappears dur- ing the early development of the stromata. The periderm, endodermis, pericycle and phloem tissues turn dark brown to black and disintegrate. The cortical tissue is crushed during the development of the stromata. The stromata vary from 460 to 530 /x thick. The perithecia, shown in fig. 15. are large, monostichous, globose to ovoid, :md immersed in the stroma. They range from 260 to 400 /i in diameter and from 350 to 370 /x in height. The height meas- urement does not include the extended ostioles, which are 135-200 /i long and 18- 30 fx in diameter. The asci are cvlindric, 90-125 X 9-12 ^, pedicellate and 8- spored. The ascospores are arranged ob- liquely in one row in the ascus and are ellipsoid to fusiform, continuous, 15-19 X 9-12 /x, and brown when mature. They are illustrated in fig. 16. The paraphyses are hyaline, 125-215 X 4.7-7.8 ^, fili- form and somewhat abundant. This Nummularia was determined as Fig. 14.— Portion of a Nummularia canker on red oak. The gray to blackstromata develop in the smooth, reddish-brown cankerous tissues. X 13^. June 1941 CARTER: OAK DISEASES IN ILLINOIS 209 N Hill miliaria cly/yrus (Schw.) Cke. by Dr. W. W. Diehl. Single-spore plantings of N uiiinnilaria riypeus, from red oak, were made on corn meal agar. Abundant germination of asco- spores occurred in 12 hours. The asco- spores germinated by sending out, ter- minally or lateral!), one to several germ tubes from each spore. Branching of the Fig. 15.— Portion ot a stroma n( Xiimmit- liiriii in virtical section. The ovoid perithecia are enibtdded in the black stromatic tissue, and the black perithecial wall separates readil> from the stromatic tissue. X 70. germ tubes occurred in 24 hours and after they were 60 /x long. One colony, which had grown froin a single spore, produced in 10 days a growth 80 min. in diameter. The average growth for several colonies was 36 mm. in diameter, produced in 5 days. Cultures of A', clypeus from single- spore plantings on corn meal agar de- \eloped a sparse growth of interwoven, gra\ aerial h)phae. The surface growth was interwoven, gra\-tan and more dense than the aerial growth. Spores placed in sterile distilled water gave an average ger- mination of 28 per cent in 17 hours. N. tlypcus failed to sporulate when grown on artificial media. A culture of this Niim- itiiilarld is shown in fig. 17. A fmigus isolated from 28 specimens of diseased oak appeared to be identical with «# *> .K • iL. ^ - » Fig. 16.—Ascospores of iV;(?HOT«/rtn'rt. The immature ascospores are hyaline to light brown, and the mature ascospores are dark brown to black. Fight ascospores develop in each hyaline a.-cus. \ 200. Fig. 17.— Culture ot Niimmulariti grown from a single-spore isolate. The aerial hyphae are gray, and the surface hyphae are gray to tan. The fungus grows vigorously and spreads rapid- 1\ on corn meal agar. known cultures of Nuinniularia clypeus. This fungus was isolated from discolored wood, stromatic tissue of cankers, canker- ous bark and discolored regions of living wood of both red and shingle oak. Diatrype Canker and Dieback I)iatr\pe cankers were found on me- dium to sinall branches of red oak in the northeastern region of Illinois. .A young canker is shown in fig. 18 and an old canker in fig. 19. Diatrype canker de- velops as a light to dark reddish-brown, 210 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 T^- Fig. 18.— Diatrype canker and dieback on red oak. The diseased tissue is light to dark reddish brown and sunken. The border of the diseased region is raised where Hving and dead tissues meet. The stromata are irregular, black, erumpent, roughened and fissured. X Y2. Fig. 19.—Diatrype canker on red oak. Por- tion of an old canker which shows a large, fissured, mature stroma that has almost cov- ered the whole cankered region. X j4. June 1941 CARTER: OAK DISEASES IN ILLINOIS 211 Fig. 20.—Perithecia ot Dialrype. .\ vertical section ot stromatic tissue which shows the arrangement ot perithecia. X 75. Fig. 21.—.Asci and ascospores ot Dialrype, \ .ich hyaline and clavate ascus contains S In aline, botulitorm, 1-celled ascospores. X 320. Miiiken region on the branch. The canker iv conspicuous because of the contrast be- tween the healthy and the diseased tissues, and it is surrounded by a callus. Dieback de\elops when the branches are completely L'irdled by cankers. The stromata of Diiitrype de\elop sub- t-pidermally, and they become erumpent at maturity. \ portion of a stroma is shown in tig. 20. Stromata are diatrypoid, black and smooth at first, but later they become Lirayish black, somewhat roughened and tl^^ured. The fissures are produced by ver- tical and longitudinal splitting of the ~trumatic tissue. The ovoid, dark, car- honous and ostiolate perithecia are shown in fig. 20. Immature perithecia are 48—53 // in diameter and 63-68 ;( high. Mature perithecia are globose and 200-225 fx. in diameter without their e.xtruded beaks, whicli are 75-85 /x long from the top of the perithecia to the ostioles at the external surface of the stromata. The ostioles are papillate, round, not compressed, and are 30—1^0 fj. in diameter. The asci, shown in rig. 21, are 8-spored. hyaline, 30—33.5 X 4.8—5.2 fjL. and somewhat clavate with a tapering base. Each ascus has a pore at its apex. The ascospores are pictured in fig. 21. They are hyaline, 6.6-9.5 X 1.6-3.3 ,u, botuliform and continuous. Known cul- tures of Diatrype were not secured on arti- ficial media. Our material agrees with Diatrype stigma (Hoffm.) Fr. as represented in Ellis ik Everhart's North .American Fungi, Second Series, No. 3,529. Phomopsis Canker and Dieback Phomopsis canker and dieback, identi- fied by isolation of the fungus from the diseased wood, was found on branches of pin, red, swamp white and white oaks. Externally, Phomopsis cankers are reddish brown, elongate, smooth and somewhat shrunken, and they have definite borders where the cankerous and living bark meet. In most of the cankers the diseased xylem tissue varies from light brown to dark brown ; and occasionally light to dark brown streaks extend into the adjacent living xylem tissue. Phomopsis was found fruiting in the diseased bark of only one canker and die- back specimen of oak—pin oak. The pycnidia in the diseased bark are black, ovoid to discoid, erumpent, 200-270 /x high and 400-470 fi in diameter. They are fundamentally laid down in the phel- Icgen-phelloderm region of the bark. Their development causes very little distortion of the underlying cortical tissue, but the overhing phellem and epidermis are rup- tured by the enlarging pycnidia. The rup- tured tissues form a triangular-shaped shield around the mature pycnidia. The conidia, a-spores, are hyaline, 7-10 X 1.5-3 fi, ellipsoid to fusoid, and continuous. In culture, Phomopsis de\elops a sparse growth of gray mycelium that spreads rapidly on corn meal agar. Pycnidia are 212 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 pioniiscuously interspersed with the m\ce- liuin. The portion of the pycnidium that grows above the agar is gray, and the por- tion that is embedded in the agar is black. Fig. 22.—Culture ot Phomopsis on corn meal agar. The gray pycnidia are produced promiscuously and are interspersed with the mycelium. Fig. 23.— Spores of Phomopsis. Both a- and 0-spores are produced on sterilized red oak twigs. The ellipsoid to tusoid, continuous, hyaline a-spores are produced in greater abun- dance than are the straight to curved or hamate, filiform, hyaline /3-spores. X 300. A culture of Phomopsis on corn meal agar is shown in fig. 22. Phomopsis from the red and swamp white oak branches produced both a- and j8-spores in culture. It was isolated from the discolored, diseased xylem and from the living xylem of cankers that showed fine, light to dark brown streaks. It was cultured not only from cankers but from the black, discolored xylem tissue of a die- back specimen of red oak. One canker from which Phomopsis was cultured had stromata of Diatrype stii/iiui on the canker- ous tissue. The p\cnidia of the Phomopsis that pro- duced both a- and /iJ-spores are black, glo- boid to o\oid, without ostioles, are subcar- bonous, and 500-1000 y. in diameter. The a- and /i-spores are shown in fig. 23. The a-spores are elliptic to fusoid, 5-10 X 2— f IX, hyaline and continuous. The /i-spores are straight to curved or hamate, normally 16-30 X 1-2.8 ju, filiform, hyaline and continuous. In one instance the /i-spores measured 28—34 X 3—5 jx. Our material from the red and swamp white oak branches agrees with Phomopsis quercina (Sacc.) v. Hohn. as represented in Sydow's Alycothecii gcrmmiica No. 1,122. Phomopsis grown from the branch cank- ers of pin oak and white oak and also from the blighted petioles of one specimen of red oak produced only a-spores in culture. The pycnidia are black, 400-500 X 330- 450 jx, globoid to ovoid, and pseudoparen- chymatous. The conidia are continuous, -1—10 X 2—4 jx, hyaline, and ellipsoid to fusoid. They are comparable in size to tlie Phomopsis spores produced in the canker- ous tissue of the pin oak and also to the a-spores of Phomopsis grown in culture from red and swamp white oak branches. CANKER DISEASES Phoma Canker Phoma cankers were found on twigs and on small to large branches of bur, pin, red, shingle and white oaks. The cankers are dark brown to black, somewhat shrunk- en and roughened, and have definite bor- ders where the cankerous and living tissues meet. In some specimens of diseased oak, dark brown to black streaks of discolora- tion are present in the living wood beyond the extremities of the cankers. This dis- coloration is similar to that of the Dothi- orella cankers shown in fig. 3. Pycnidia develop in the phellogen-phelloderm re- gion. The overlying host tissue is rup- tured by the developing pycnidia, which are erumpent at maturity. Five Phoma cankers—two on twigs, two on small branches and one on the trunk of a small tree—were found on red oak. The pycnidia in these cankers are Jur 1941 CARTER: OAK DISEASES IN ILLINOIS 213 black, globoid to slightly ovoid, ostiolate, and 150-200 ji in diameter. The conidia are hyaline, ,?-,?. 5 X 1-2.5 ju, oblong to fiisoid, and continuous. From one of the two twig cankers, Plioma was obtained in culture; Cephalo- sporium was obtained from the other. Dothiorella was obtained from the trunk canker and from one branch canker ; Peni- cilliuni and Cephalosporiuin were obtained from the other branch canker. The Phomii from the twig canker, cultured on corn meal agar, produced black, globose pyc- nidia 80-110 fx. in diameter. The conidia are oblong to fusoid, h\aline, 3.3-3.6 X 2.5-3.2 ft,, and continuous. Plio/iia was obtained in culture from 22 canker specimens of diseased oak that had no Phoinii pycnidia in the cankerous tissue. One of these cankers was on bur oak, 2 on pin oak, 12 on red oak, 1 on shingle oak and 6 on white oak. Pho/iin was grown from the living wood that showed dark brown to black streaks in 7 of these 22 specimens and from the cankerous tissue of the remaining specimens. Phoriiii was the only fungus obtained in culture from 17 of the 22 diseased oak specimens mentioned above. It was ob- tained in association with other fungi from the remaining 5 specimens. The asso- ciated fungi were Jlteniaria, Cephidu- sporiiini and Dotliiorellti. CoryiifUiii was found fruiting on 1 and Cyl'jsp(jni on 2 of the 22 specimens. Cultures of Phoriia from the above-de- scribed sources produced pycnidia on corn meal agar. The pycnidia, illustrated in fig. 24, are black, globoid, pseudoparen- chymatous, and 50-200 [i, in diameter. Conidia are hyaline, 1.5—I- X 0.7-2.5 fi, continuous, and oblong to fusoid. The fungus produces a dense growth of radiate mycelium, which develops slowly. Black pycnidia are interspersed with the myce- lium. A culture of Phoniii is shown in fig. 25. The dense growth of surface hyphac is tan to brown with a 1 mm. marginal growth of white hyphae. The sparse growth of aerial hyphae is white to gray. All of the pycnidia and conidia of Phoiiui described above are sufficiently similar in size and shape to be regarded as from one species. This species compares more closely with the morphological description of Phoina aposphaerioides Briard &: Hariot (Saccardo 1892) than with the morpho- logical descriptions of other species of Ph'iiiiii on (Jiii'iiiis. A second PhniiKi was found fruiting on the blighted petioles of a post oak. This Fig. 24.—Pycnidia of Phoma. NunitTous black, globoid, pseudoparenchymatous pyc- nidia are produced on corn meal agar. X 140. • Fig. 25.—Culture of Phonia on corn meal agar. Numerous black pycnidia develop in more or less concentric circles. fungus was grown in culture from these diseased petioles and from blighted petioles of another post oak. On the petioles, the second Piwma pro- duced dark brown to black, ovoid, pseudo- parenchymatous pycnidia 350-450 fx in diameter. The conidia are hyaline, 6-8.5 X 2.8-3.4 ;u,, continuous, and ellipsoid to fusoid. On corn meal agar the fungus pro- duced dark brown to black, ovoid, pseudo- parenchymatous pycnidia 250-400 ;u, in diameter, and conidia that are hyaline, 6-9 X 1.5-3 (u,, and oblong to fusoid. T his Phoma was associated with only the blighted petioles of twig blight speci- mens of oak. In this disease the leaves wilt and then turn brown to reddish brown during the summer (July and 214 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 August). The petioles, externally and internally, turn brownish purple, and the twig tips die back 1 to several inches. The bark turns brown and then dries and shrinks tightly around the wood. This second Phoma agrees with the morphological description of Phoina quer- cina (Peck) Sacc. (Saccardo 1884). Fusicoccum Canker Fusicoccum cankers, shown in figs. 26 and 27, are slightly sunken, dark brown to brownish-black areas, with conspicuous borders where the cankerous and living tissues meet. Erumpent stromata develop in the cankerous tissue. Deep fissures, which extend partially to completely across the cankerous bark, are very conspicuous. Dark brown discoloration of the wood beneath the cankerous bark does not extend into the living wood beyond the margin of the canker. Fusicoccum was isolated from two cankers on red oak and from brownish- purple, blighted petioles of two diseased oaks (black and post oaks). The brown- ish-purple discoloration is most apparent at the base of the petioles; it fades to a light brown color where the petioles and the brown leaf blades unite. Abscission layers are formed at the junction of the petioles and twigs, and the leaves are easily re- moved from the twigs. Stromata are laid down fundamentally in the phellogen-phelloderm region of the bark. Their development causes very little distortion and crushing of the underlying cortical cells. The overlying phellem and epidermis are ruptured as the stromata en- large and mature. The mature stromata appear dotlike in the cankerous tissue. The stromata, 700-1400 /x in diameter and 250-450 jx high, are black, ovoid to conoid, erumpent, multilocular and with a sterile central region of pseudoparen- chymatous hyphae. A vertical section of a stroma is shown in fig. 28. The conidial cavities are ovoid to elongate and some- what irregular in outline. Conidia, shown in fig. 29, are hyaline, 6-12 X 2—1- /*, ellipsoid to fusoid, and continuous. Conid- iophores are hyaline to subhyaline, 6-12 X 1.5-3 n, and bacillar. Fusicoccum produces white mycelium on corn meal agar. A few promiscuously scattered stromata that are black, 1300- 1500 fx. across, ovoid to globoid, and multi- &*, Fig. 26.—Fusicoccum canker on red oak. The shrunken, dark brown to brownish-black, cankerous tissue contains numerous black, ovoid to conoid, erumpent stromata. Numer- ous fissures extend partially to completely across the cankered region. X 1. locular are interspersed among the hyphae. The pycnidial locules are globoid to ovoid, black, and 650-800 jx in diameter. The conidia are hyaline, 6-13 X 2.5-4 jx, con- June 1041 CARTER: OAK DISEASES IN ILLINOIS 215 'mr'n :s Fig. 28.— Portion of a stroma of Fiisicocciim trom red oak. This vertical section shows the internal cavity of the stroma and the hiack stromatic tissue that has pushed through the host tissue. X 5S. ^ \ ^/ Fig. 27.- Kusicoccum cankers on red oak. The erumpent stromata and fissures in the shrunken, cankerous bark are conspicuous in the larger canker, which has developed around the base of a twig. The smaller canker, below, has developed trom infection through an in- jury. X 3. tinuous, and they are ellipsoid to fusoid. Our material agrees with Fusicoccuin queriinum Ell. & Ev. as represented in North American Fungi, Second Series, No. 3,360. Saccardo (1899) considered /'. querciinuii Ell. & Ev. identical with /". El- Usiaiium Sacc. & Syd. and not with /•". qiierciiium Sacc. (Saccardo 1884). There- fore, according to the classification of Sac- Fig. 29. —Spores of Ftishoiniiii. The spores are hvaline, ellipsoid to fusoid, and continu- ous. X 320. cardo (184')), the material that we :tudied is F. F.Uisiaiiiuii Sacc. ^ Syd. Sphaeropsis Canker A portion of the only Sphaeropsis canker found on oak, on a red oak twig, is shown in fig. 30. This canker is reddish brown, is promiscuously dotted with Sphaeropsis pycnidia and is bounded b\ a definite bor- der made conspicuous b\ the contrast be- tween the smooth, reddish-brown, dead bark of the canker and the adjacent, liv- ing, dark green bark. The dead wood be- neath the cankerous bark is discolored chocolate brown and is bordered by a black region adjacent to the healthy wood. This discoloration in the wood extends down the twig approximate!) 1 inch beyond the base of the cankerous bark. 216 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Alt. 6 The pycnidia are black, ostiolate, sep- arate to cespitose, globose to ovoid, 650- 860 (n in diameter and 400-600 /i high. They arise fundamenta]l\- in the phellogen- phelioderm region of the bark. The over- l\ing phelleni and epidermis are broken when the pycnidia mature and become erumpent, and there is ver\' little crushing or disintegration of the underlying tissues. The broken host tissues form oval to cir- Fig. 30.— Portion ot" a Sphaeropsis canker on red oak. The reddish-brown, smooth, shrunken cankerous tissue contains numerous black, globose to ovoid, erumpent pycnidia. X 1. Fig. 31.—Spores of Sphaeropsis. \ cross section of a pycnidium which shows the brown, 1-celled, ovoid to ellipsoid spores and the black pseudoparenchymatous pycnidial tissue. A 150. h 1941 CARTER: OAK DISEASES IN ILLINOIS 217 cular shields around the erunipent p\ c- iildia. The conidia, shown in the cross section of a pycnidiiim in fig. 31, are brown, 15-25 X 8-11 /i, continuous, and o\(iid to ellipsoid. The conidiophores are hyaline, rodlike, 6-9 X 1.5-2.5 jx, and the oval ostioles are 15—25 ix in diameter. This fungus was not grown in culture. Our material compares closely with the morphological description of SplKierofisis queriiiiuni Cke. .^' Harkn. (Cooke ^' llarkness 1884). Bulgaria Canker Apothecia were obtained from Bulgaria cankers on two black oak trees. The cankers were located on the trunks ap- Fig. 32.—Ascospores of Bulgaria. Kacli hyaline, cylindric, pedicillate ascus contains 4 to 8 brown, ovoid to suboblong, continuous ascospores. .\ IM). proximately 2 feet above the soil line, .'^mall and oval to large and irregular areas of the bark had been killed. Ihe camb.um under the dead bark was tan to light brown and was water soaked. Black zone lines were present in the underlying wlem tissue. Killing of the cambial re- gion was followed b\ general decline and finalU death of the infected trees. Several attempts to grow the fungus on artificial media (corn meal agar, po- tato dextrose agar and acidified potato dextrose agar) from ascospores and from apothecial tissue were unsuccessful. As- peif/Uliis. (Ji-fihiihsfioriuni , Fusariuin and an unidentified fungus were obtained in culture from the apothecial tissue of Bul- ijaria. The apotiiecia of Bulyaria are black, substipitate to sessile, gelatinous to fleshy. and cupulate « ith a wail 71)0-1 800 jx thick. Asci are hyaline, 40-60 X 6-10 II. cjlindric, pedicillate and 4- to 8-spored. The ascopores, fig. 32, are brown, 7-15 X 4—6.5 fx. continuous, and o\oid to ellip- soid or suboblong. Paraphyses are sub- hyaline to light tan, 75-110 X 0.7-1.7 IX. and filiform. Our material agrees with Bulyaria iii- quiiians ( Pers. ) Fr. as represented in Ellis' North American Fungi No. 448. DIEBACK DISEASES Coniothyrium Dieback Coniothyrium branch and twig dieback was found on black, bur, pin, red, swamp white and white oaks. The Con'wlhyriinn fungus was isolated from diseased bark, blighted twigs and discolored regions in the live wood that extended from the dead wood in specimens of dieback. In this type of dieback the diseased bark is light reddish brown to dark brown, smooth, slightly raised, and continuous with the surrounding living bark. There are no pxcnidia or fissures in the diseased bark. In some cases streaks that are light to dark brown and fine to broad extend from the discolored dead wood beneatli the diseased bark into the living wood be- low the dieback region. On corn meal agar, the Coniothyriiun isolated from oak develops dark tan to Fij. 33.- Culture of Cuniuthyrium on corn meal agar. The dark brown to black, partially submerged, sphaeroid pycnidia develop in old cultures. 218 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 brown mycelium, fig. ii. The mycelium is white when young but becomes tan to brown with age. A dense growth of sur- face hyphae and a very sparse growth of aerial livpbae develop in culture. Pycnidia develop as partially submerged, dark brown to black, pseudoparenchyma- V c # 9 9 • % Fig. 34.—Spores of Coniolhyrium. They are ovoid to subcylindric, olivaceous and 1- celled. X 430. tous, spheroidal structures with flattened bases; they are 150-500 /x in diameter. The conidia, Hg. 34, are ovoid to sub- cylindric, 4-7 X 3-4.5 ft., olivaceous and continuous. This Coniothyrium compares closely with the morphological description of Coniolliyritii/i trunciseduni Vestergr. (Sac- cardo 1899). Pyrenochaeta Dieback Pyrenochaeta dieback was found on pin oak and white oak. The diseased bark is dark brown to brownish black and is shrunken; most of it is smooth. Fungous fructifications are not present in the can- kerous tissue. The underlying wood is dark brown to black and has broad streaks of discoloration that extend into the living wood. Pyrenochaeta was isolated from discolored living wood of pin oak and white oak about one-half inch below the base of the dieback regions ; also from one twig blight specimen of white oak. On corn meal agar the fungus produces small, globose to ovoid, pseudoparenchyma- tous, dark brown to black, ostiolate pyc- nidia, normally 60-100 /x in diameter, and with setae. The measurement of the pycnidia of one culture from white oak is 335-535 /x in diameter and, in a second culture, 100-250 ^i in diameter. Two pycnidia are shown in fig. 35. The ostioles are circular and H-10 jx in diameter. The setae, shown in fig. 35, are brown, septate, 10-50 X 2—1 IX., straight to curved, and tapering toward the apices. Conidia of this Pyrenochaeta are very small, hyaline, 1.5-4 X 0.7-3 /x, fusiform, continuous, and they are ovoid to ellipsoid in shape. Fig. 35.—Pycnidia and spores of Pyreno- ch:jeta. The small, globose to ovoid, dark brown to black pycnidia have septate, straight to curved, tapering, brown setae especially around their ostioles. The spores are minute, hvaline, continuous, (usiform and ovoid to ellipsoid. X 170. Fig. 36.— Culture of Pyrenochaeta. The tan to dark brown mycelium grows slowly and pro- duces a dense mat on corn meal agar. June 1941 CARTER: OAK DISEASES IN ILLINOIS 219 The mycelium is light to dark brown. A culture is shown in Hg. 36. The sparse growth of aerial hyphae is gray to light brown. The dense growth of surface and subsurface hyphae is light to dark brown with a 1 mm. marginal growth of white hyphae. This Pyrenocliaeta does not appear tn compare morphologically with any of the described species of Pyrenochaetii. in widely scattered sections of Illinois; linwe\er, they were noticed especially in the northeastern section of the state. In nearly e\ ery instance, staghead and gen- eral decline of oak were associated with root disturbances, especially with root rot. In the stagheaded trees examined, young roots and the white wood of older roots Pyrenochaeia minuta sp. nov. Mycelium in culture light to dark brown in mass, with sparse, gray to light brown aerial hyphae and abundant light to dark brown surface hyphae; pycnidia scattered, globose to ovoid, sooty brown to black, 60-535 /it, mostly 60-100 ju, in diameter; ostioles round, 8-10 yu. in diam- eter; setae brown, septate, straight to cur\ed, tapering toward apex, 10-50 X 2—I- /i; conidia hyaline, minute, fusiform, continuous, o\'oid to ellipsoid, 1.5—1 X 0.7-3 ij.. Mycelio in cultura dilute usque atrato brunneo in niassa, hyphis aeriis sparsis griseis usque dilutis brunneis, hyphis in superficie medii abundantibus dilutis usque atratis brunneis, picnidiis sparsis globosis usque ovoideis tuhginosis usque nisris 60-535 M ut plurinum 60-lCO ii dianietris cum ostioMs rotundatis 8-10 n diametris et setis brunneis septatis rectis usque curvatis ad apicem attenuatis 10-50 x 2-4 ti, conidiis hyahnis niinutis tusitormibus continuis ovoideis usque ellipsoideis 1.5^x0.7-3 M. Type specimen : Pure culture isolated from the cortical parts of an infected branch of Quercus paltistris Aluench., col- lected bv I. C. Carter at Xenia, Cla\ Countv,' iflinois, October 8, 1937, 111. Nat. Hist. Surv. Ace. No. 27,082. Other specimens cultured from branch of Quercus (ilha L. collected by J. C. Carter at Galena, In Daviess Countv, Illinois, October 28,' 1937; twig of Q. alba collected by J. C. Carter at Lake Forest, Lake Count\ . Illinois, September 25, 1937. ROOT ROT Armillarja Root Rot Observations were made in the course of this investigation to determine the cause of staghead, general dieback and the sudden dying of numerous oak trees. These pathologic conditions of oak were observed Fig. 37.— Culture of Jrmillaria. The red- dish-brown rhizomorphs are produced in abun- dance on corn meal agar. were affected by a white rut. The brown wood of the older roots showed a gradual change from the early to the late stages of rot. In the earl\ stage of rot the brown wood of the older roots becomes lighter brown, but later it gradually changes to gray, which is sometimes mottled. Finally, in the late stage of rot, the wood becomes white, soft and spongy, and in time it crumbles away and leaves a cavity in each infected root. From specimens of this 220 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 Fig. 38.—Young sporophores of Armillaria. They were found developing in tlie soil about 1 foot from the base ol a bur oak tree and above the infected root. The reddish-brown to black rhizomorphs are attached to the young sporophores. X 1. white, heart-rot wood as well as from rhizomorphs, Armillaria ?neUea (Vahl.) Quel, was isolated. A culture of A. mel- lea with rhizomorphs that permeate the potato dextrose agar is shown in fig. 37. In the roots of many of the diseased oaks, rhizomorphs of Arinillaria, shown with attached sporophores in fig. 38, de- velop in the cambial region and in root cavities. In the late stage of staghead, the rhizomorphs are frequently found under the bark at the base of the large roots and in the root crotches. Rhizomorphs may enter through wounds in the root crotches at or below the surface of the soil. Thev are present in the duff at the base of seri- ously infected trees and frequently are found spreading through the soil for dis- tances of 25 feet or more. In the earlv stage of staghead, rhizomorphs are asso- ciated with the death and rotting of the very small feeding roots. Gradual de- struction of these roots reduces the feed- ing capacity of the root system and limits the amount of foliage that can be sup- plied with plant food and water. An in- adequate supply of plant food and water causes the gradual drying back and dying of the extremities of the branches, and in time the affected trees show staghead. Armillaria infection at the base of a large root quickly reduces the amount of food and water supplied by the root and causes dieback or death of the branches that are supported by the infected root. Infections of this type in several roots cause the rela- tively sudden death of the tree. In the soil, rhizomorphs are dark red- dish brown to black externally, cylindric. Fig. 39.—Sporophores of /Irtnillaria. This group of sporophores developed at the base of a dead bur oak root. X ?i. June 1941 CARTER: OAK DISEASES IN ILLINOIS 221 little branched, 0.5-3 mm. in diameter, and they contain cream to white hyphal strands. The rhiznmorplis that develop in the cambial region of the roots and tree trunks are dark red to reddish brown, Hattened, much branched, 0.2-3 mm. broad, and they contain cream to white hyphal strands. Sporophores of Arniillaria develop, usu- ally in October in Illinois, on the dead bark of the trunks and the roots of in- fected trees. Also they may be found on the ground at or near the base of the infected trees and sometimes at distances of several feet from them. A group of immature sporophores taken from the root of an oak ma\' be seen in fig. 39. MISCELLANEOUS FUNGI CylindTOsporium Cylindrosporiuiii was found fruiting in the diseased tissue of one dieback specimen of shingle oak. The fungus was not grown in culture from this specimen nor from any other specimens of diseased oak. How- ever, Coryneuin was grown in culture from the diseased tissue of this specimen and was most likely the fungus responsible for the dieback. The Cylindrosporium evi- dently developed in the bark after the branch had become infected with Cory- neuin. The diseased bark of this shingle oak specimen is light to dark brown, slighth- shrunken and for the most part smooth ; however, where the numerous Cylindrn- sporiiint acervuli have been produced there Fig. 40.— Accrvulus of Cyiindrosporitim on shingle oak. A vertical section of an acervulus whicli shows the position ot the acervulus in re- lation to the host tissues. X 75. are blisters. An acervulus is shown in ver- tical section in fig. 40. Acervuli are dark brown to black, pulvinate and immersed. Thev become erumpent at maturitv and are 530-1100 ^ in diameter and 130-400 /J, high. The acervuli arise fundamentally in the phellogen-phelloderm region of the bark and at first cause very little distor- tion and disintegration of the cortical cells. As they expand in growth and become ma- ture, the\- rupture the o\erlying phcllem and epidermis, which form shields around Fig. 41.—Spores of ( tachcd to a portion ot" an ai are hvalinc, acicular and X 500. 111,1),ji [1,1 ijiiii at- ^ulus. The spores aight to curved. them. The conidia, shown in fig. 41, are hyaline, 20-40 X 1-3 /i, acicular, 1- to 2-celled, and straight to curved. This fungus does not appear t(j com- pare morphologically with any of the de- scribed species of Cylindrosporiiini that have been found on Oueiciis. Cylindrosporium quercinum sp. nov. Acer\ uli scattered, dark brown to black, pulvinate, innate, becoming erumpent, 530-1100 II in diameter, 130-400 ^ high, inhabiting an elongated, light to dark brown diseased region of the branch ; conidia hyaline, acicular, continuous to I -septate, straight or slightlv curved, 20- 40 X 1-3 IX. Acervulis sparsis atrobrunneis usque nigris pulyinatis innatis dein crumpentibus 530-1100 M diametris 130-400 /x altis regionein elongatam dilutam usque atratam brunneam aegrotam rami incolentibus, conidiis hyalinis acicularibus continuis vel 1-septatis rectis curvulisve 20-40 X 1-3 ^. Type specimen: Collected by G. H. Roewe, Cartter, Marion County, Illinois, on branch of Ouercus imbricaria Michx., September 17, 1936, 111. Nat. Hist. Surv. Ace. No. 27,081. 222 ILLINOIS NATURAL HISTORY SURVEY BULLETIN \'ol. 21, Art. 6 Rhodosticta Rhdiiosticta was found fruiting on a single specimen of dieback, taken from a pin oak growing in a nursery row. The diseased branch, approximately 1 inch in parenchymatous hyphae that compose the bases of the stromata. The overlying phellem and epidermis are ruptured and forced back to form a collar around the erumpent stromata. Erumpent stromata are shown in fig. 42. Fig. 42.—Dieback of pin oak with Rhodosticta fruiting in the diseased tissue. The central region of the shrunken and smooth diseased bark is pale yellow but it blends into a light brown and then into a dark brown at the border. The scattered, ovoid to irregular, red stromata are present in the discolored, diseased tissue. X 2. diameter, had become infected through the stub of a lateral. The color of the diseased bark in the central region is white to pale yellow, blending into a light brown and then into a dark brown toward the margin. A raised region of callus tissue contrasts sharply with the adjacent diseased bark. This con- trast marks a definite separation of the living and dead tissues. Light brown dis- coloration of the dead wood beneath the diseased bark does not extend into the living wood. Stromata are laid down fundamental!) in the phellogen-phelloderm region of the branch. These tissues and the underlying ,,..,c rn,j- ^ . • ,, ,. . ,1 Fig. 43.—stroma or Rhodosticta. A vertrcal cortex are partially dismtegrated and ^^^^,^„ ^f ^ .^oma which shows the variable crushed by the development of the pseudo- shape and arrangement of the pycnidia. X 29. June 1941 CARTER: OAK DISEASES IN ILLINOIS 223 rhe\' are red, oxoid, witli an irregular outer surface, not crustose, 1200-1500 /x In diameter and 800-1000 ,jl high. The p.\cnidial cavities, visihle in the vertical section of the stroma, illustrated in fig. 43, are ovoid to irregular, promiscuously dis- persed throughout the stromatic tissue and variable in size. They are of three types: small, oval cavities, 60-65 X 25-35 /* ; large, oval cavities, 160-180 X 30-40 Fig. 44.—Spores of RhodosluUi. Tlu spurcs are minute, ovoid to ellipsoid, and hvaline to subhyaline. X 860. jj.; and long, narrow cavities, 115-135 X 70-85 IX.. The conidia, shown in fig. 44, are hyaline to subhyaline, 2.8-3.5 X 1-2 II, and ovoid to ellipsoid. The fungus was not grown in culture. Our material does not compare with Rhodostiitti Cariigdiiae VVoronichin (Sac- cardo 1913). The present report is be- lieved to be the first of Rhodostkta on Quercus. Rhodostkta quercina sp. nov. Stromata scattered, red, tubercular, not crustose, 1200-1500 ^ in diameter, 800- 1000 /i high, inhabiting a light to dark brown diseased region of the branch ; pycnidia ovoid to irregular, immersed, 60- 180 X 25-85 n; conidia hyaline to sub- hyaline, ovoid to ellipsoid, 2.8-3.5 X 1-2 ix. Stromatibus sparsis rubris tuberculitormibus non crustosis 1200-1500 m diametris 800-1000 m altis regionem dilutam usque attratam brunneam acgrotani rami ineolcntibus, picnidiis ovoideis usque irrcgularibus immersis 60-180 x 25-85 n, conidiis hyalinis usque subhyalinis ovoideis usque cilpisoideis 2.8-3.5 x 1-2 ^ Type specimen : Collected by J. C. Carter, Onarga, Iroquois County, Illinois, October 25, 1935, on branch of Quercus palustris Muench., 111. Nat. Hist. Surv Ace. No. 27,083. Cephalosporium Cepludosporium was obtained in culture from 27 specimens of diseased oaks, black, red, shingle and white. It was isolated from cankerous wood and bark and from discolored living wood of red, shingle and white oaks, and from a living twig of black oak that had blighted leaves. Ceph- (ibispfjtiuni was the onl\- fungus isolated from the living wood below cankers of three specimens of red oak and of one specimen of white oak. In each case th fungus was isolated from discolored, light to dark brown living wood that was taken at points 1 to 3 inches below the cankers. Cfph/ilosporiufii was obtained from most specimens in association with other fungi, including Alteniaria, Coniothyrium, Co- ryni'ui/i, Cytospora, Pemcillium, Pesta- I'jliri, Phonia and Dothwrella. The only cultures of Cepluilosporiuin not associated with other fungi were obtained from dis- colored dead wood and, as pointed out above, from discolored living wood. On corn meal agar the surface of old cultures of this Cephalosporium appears granular or pulverulent. The appearance is due to the numerous conidia produced. The fungus grows and spreads rapidly over the surface of the agar. Conidio- phores, produced on septate, hyaline, branched hyphae, are unbranched, variable in length hut approximately 250-300 X 2~i /J., hyaline and filiform. Conidia are capitate, hvaline, ellipsoid to ovoid, ses- sile, 2-3 X 1.5-2 IX to 7.5-10 x 3-3.5 ,x, most frequently 3-4 X 1.5-2 /*, and pro- duced acrogenously in globose heads on the conidiophores. Nigrospora Niyrospora was isolated from two speci- mens of diseased oak : one isolate from a blighted twig of post oak and one from a blighted petiole of pin oak. The blighted 224 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 twi't: was hroun internall\ and liad blight- ed leaves witli purplish petioles attached. Tlie blighted petiole was shriveled, dead purplish internally and e.xternally, and was attached to a twig that had h\per- Fig. 45.— Culture o\ Nigrospora. The white to gray, abundant growth of mycelium devel- ops on corn meal agar. Fig. 46.—Spores oi Nigrospora. The black, smooth, globose to ovoid spores develop singly on doliform basidia. X 320. trophied buds. Siyrnspnni was not found fruiting on the diseased wood of any speci- mens of oak. Both Xit/rosporii and Cor- yiiriiin were cultured from the blighted twig of post oak; Dothinrclln and Alter- iiiiria, as well as Nii/ros/tora, were cul- tured from the blighted petioles of pin oak. When grown on corn meal agar, the Niffrospora discussed here develops a dense surface and aerial growth of hyphae that is white and somewhat powdery. A culture is illustrated in fig. 45. Produced on erect conidiophores, the black, exogenous, smooth, globose to ovoid, acrogenous conidia, shown in fig. 46, develop singly on doliform basidia and are 11.5—22 /i, most of them approximating 15.5 /x, in diameter. Sometimes the conidiophores are branched, and several conidia develop on each of the branched conidiophores. This fsitjrospora agrees with Niffrospora sphaerica ( Sacc. ) Mason on elm, discussed by Harris (1932). Harris' material was determined by E. W. Mason of the Im- perial Mycological Institute. Cunninghamella Cutiiiinghamella was isolated from a specimen of red oak dieback. The dieback had developed where the branch was broken. The diseased bark was reddish brown, shrunken and cracked crosswise. The xylem tissue under the bark was dis- colored dark brown to black with fine streaks that extended into the living xylem below the base of the dieback region. Im- mature fungous fruit bodies were present in the diseased bark. The fungus was obtained in culture not only from dead dis- colored wood but from living discolored wood taken from an area approximately 1 inch below the base of the dieback region. This Cunniiiffhamella develops a sparse growth of yellowish-tan surface mycelium on corn meal agar. Conidia are borne in abundance on erect, tan conidiophores. Sporangia and sporangioles are lacking. The condiophores, shown in fig. 47, are continuous with the hyphae and are tan, straight or curved, 75-300 X 4-6 /u,, fre- quently joined to the hyphae at right angles and apically swollen. The swollen apices of the conidiophores are 9-15 /i in diameter. Conidia, shown in fig. 47, are globose, 2.9-3.3 fj. in diameter, tan and June 1941 CARTER: OAK DISEASES IN ILLINOIS 225 cells aie li\ahne and somewhat conoid. The intermediate cells, 3 in each conidium, are brown : the upper 2 dark brown and itaim Fig. 47. S]M,ris ,nui i unuli. .p h, m'l s of C:ill- ninghiimella. The glohosf, tan, cchinulate spores are produced on erect, tan, apieally swollen conidiophores. X 200. echinulate. The h\phae are coenocvtic, hyaline and 2.8-3.5 /i in diameter. This is believed to be the first report of a CunninghaineUd cultured from dis- eased oak wood ; no attempt has been made to secure zygospore production, and the species has not been determined. Pestalotia Festalotia was isolated from living tissue of a black oak twig that had blighted leaves attached to it. The twig was not dis- colored internally, but the leaves were dead and brown, and the petioles were purplish, shriveled and dead. No fungus was fruiting on the twig or on the at- tached petioles. Cephalosporiuin and Dothiorella as well as Pestalotia were ob- tained in culture from the twig. This Pestalotia produces a sparse growth of light to dark tan surface and aerial mycelium on corn meal agar. Scattered acervuli are dark brown to black, ovoid to globoid and 300—1-00 yu, in diameter. The conidia, shown in fig. 48, are clavate, mostly straight, 5-celled, not constricted to slightly constricted at septa, 20-30 X 6-9 /i, and with setae (usually 4) on each apical cell. Basal cells of the conidia are hyaline and ellipsoid to conoid. Apical . ?., %«» 1 Fig. 48.—.Spores of Pcslalolia. The clavate, .S-celled spores have hyaline apical and basal cells, and brown intermediate cells. There are usuallv 4 setae on the apical cell of each spore. X 200. the lower 1 light brown to tan. The setae are 25-40 X 2.8-3.4 ,x and hyaline. The basidia are 9-12 X 1-2 jx and hyaline. This fungus was determined as Pesta- lotia clavispora Atk. (Atkinson 1897). The determination was verified by Dr. E. F. Guba. Chaetomium A single isolation of (jhaelomium, a cul- ture of which is shown in fig. 49, was se- cured from brownish-black, discolored live wood of white oak. The discolored live Fig. 49.—Culture of Chaetomium. Numer- ous brownish-black, ovoid, membranous per- ithecia develop on corn meal agar. 226 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 wood was adjacent to the base of a dis- eased region that showed dieback. Both Chaelrjinium and Cytnspora were obtained from this specimen of dieback. The living wood from which Chaetomium was iso- lated showed black, discolored streaks that appeared to be identical with the black streaks that are commonly associated with Dothiorella infection of oak, as illustrated in fig. 3. The Chaetomium discussed here pro- duces appendaged brownish-black, ovoid, membranous perithecia in abundance on corn meal agar. The perithecia are 375- 425 /i. in diameter and 270-300 fi high. Appendages are dark brown to black, long wavy to spiral (wavy at base and spiral toward top of perithecia) and, above the perithecia, form dense tufts that measure 610-650 /* in diameter and 400-415 /^ high. The asci are hvaline, ovoid to cla- vate, 8-spored, 40-50 X 12-14 ^, and tapering to 6-7 fi in diameter near the base. Ascospores are olivaceous, 9.3-1 1 X 7-9 IX, and lemon shaped. This Chaetomium was identified as Chaetomium globosum Kunze by Dr. J. A. Stevenson. Alternaria Alternaria was frequently obtained in culture from diseased bark and wood and occasionally from blighted petioles of black, bur, chinquapin, pin, post, red, shingle, swamp white and white oaks. Only one isolation of Alternaria was obtained from the living wood of a specimen of diseased oak—white oak. This specimen showed fine streaks of black discoloration that extended from a canker into the liv- ing wood a few inches up the branch. Large, black, carbonous and immature stromata, characteristic of the stromata of Nummularia, were present in the dis- eased tissue. The Alternaria isolated from oak is similar to the Alternaria that is frequently obtained from diseased woody tissues of other hosts. A culture of the Alternaria from oak, grown on corn meal agar, is shown in fig. 50. The dense growth of surface and aerial mycelium is dark brown to almost black, and conidia are produced in abundance. The conidia are dark brown to almost black, 9-46 X 6-12 /x, averag- ing approximately 21 X 9 /i, muriform, Fig. 50.—Culture of Alternaria. This fungus produces a dark brown mycelium that grows rapidly over the surface of corn meal agar. catenulate, with 1 to 6, usually 3 to 4, transverse septa, and with none to 3, usu- ally 1 to 3, longitudinal septa. Penicillium Penicillium, fig. 51, was obtained in cul- ture from specimens of diseased living and dead wood of oak, including red, white and an unidentified species. It was ob- tained from living wood that showed dark brown to black, discolored streaks and from dead wood at the junction of the Fig. 51.—Culture of Penicillium. The gray to pale green mycelium develops on corn meal agar. Abundant production of spores causes the mycelium to have a granular surface ap- pearance. 1941 CARTER: OAK DISEASES IN ILLINOIS 227 li\ing and dead wood of a single dieback specimen of red oak. Scattered, black, erumpent stromata of Cytospora were present in the diseased bark of this par- ticular specimen of dieback. The dis- eased bark was dark brown and was shrunken and attached closely to the un- derlying brown to black, discolored wood. Penicilliuiii, Cephalosporin iii and an un- identified fungus were obtained from a second specimen of diseased red oak. Both Penicilliii/n and Dothiorella were obtained from a specimen of diseased white oak ; Phoma and bacteria, as well as Penicilliii/ii, from the diseased wood of the unidentified species of oak. The conidia of PemcilUuni are hyaline. 4. -I—4.8 X 3.4—3.8 /x, ovoid to globose, and catenulate. The light green mycelium develops as concentric circles of sparse and dense growth that spreads rapidly on corn meal agar. SUMMARY In this investigation it was found that in Illinois diseases of oak, namely, cankers, dieback, twig blight and root rot, are im- portant in the decline and death of trees in nursery, shade and ornamental plant- ings and in native stands. Numerous fungi, of which 22 are described in this paper, were associated with cankers, deep wood infections, dieback and twig blight. Some of the fungi associated with cankers fre- quently were found fruiting on or were isolated from specimens of dieback and twig blight. It was apparent, in many cases, that canker infections developed into dieback when the infected branches were completely girdled b\' the in\ading fungus. The fungi associated most consistently with canker and dieback of oak were species of Dothiorella, Coryneum, Cyto- spora, Sum malaria, Diatrype and Phom- opsis. Those associated principally with canker diseases were species of Phoma, Fusicoccum, Sphaeropsis and Bulgaria. Those associated mainly with dieback dis- eases were species of Coniothyrium and Pyrenochaeta. Dothiorella quercina (Cke. ik Ell.) Sacc. and Coryneum Kunzei Corda were the fungi associated most frequently with the diseases of oak. The fungi de- scribed in this paper can develop on dead oak wood as saprophytes. Many of them are potential parasites of oak trees, espe- cially when the trees are growing under adverse conditions. This investigation was made on dis- eased material of black, black jack, bur. chinquapin. Hill's, pin, post, red, shingle, swamp white and white oak. Inoculation trials were made with Dothiorella quercina and with Coryneum Kunzei. Black, red and white oaks inocu- lated with D. quercina became infected and showed canker and dieback symptoms typical of those described as characteristic of Dothiorella canker and dieback. D. quercina was reisolated in pure culture from the inoculated oaks. Two of the three white oaks inoculated with Coryneum Kunzei died within 1 month after they were inoculated ; how- ever, C Kunzei was not reisolated from either of these two oaks. The third white oak inoculated with C. Kunzei showed no symptoms of infection at the end of 21 months. LITERATURE CITED Anderson, H. W. 1922. Notes of new diseases of economic crops in Illinois, 1919-1921. III. .Acad. Sci. Trans. 15:130-40. Anonymous 1930. State of Xev Dept., .Ann. 1930:202-3. York. Conservation Rep. to Legislature 1931. State of N'ev Dept., .Ann. 1931:168. State of N'ev Dept., Ann. 1934:334-5. York. Conservation Rep. to Legislature York. Conservation Rep. to Legislature Ashcroft, J. M. 1934. P.uropcan canker of black walnut and other trees. W. Va. .Ag. Exp. Sta. Bui. 261. Atkinson, G. F. 1897. Some tungi tn I'niv. BuKS:!- ^0. .Alabama. Cornell Babcock, D. C. 1915. .A new scarlet oak disease. Phyto- path. 5:197. 1910. Diseases of forest and shade trees. Ohio .Ag. Exp. Sta. Monthly Bui. 1:337-8. 228 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 Bavendamm, W. 1936. Dolhiiiia twxia on ."American oak (trans, title). Tharandter Forstl. Jahrb. 86(4-5) :273-5. 1935. |Exp. Sta. Rec. 74:805.] Bidwell, C. B., and W. C. Bramble 1934. The .Strumclla disease in southern Connecticut. Jour. Forestry 32: 15-23. Boyce, J. S. 1938. Forest pathology, pp. 110-5, 284, 287, 310. McGraw-Hill Book Com- pany, Inc., New York. Braid, K. W. 1924. Some observations on Fistulina hepatica and hollow, stag-headed oaks. Brit. Mycol. Soc. Trans. 9: 210-3. Bramble, W. C. 1934. Occurrence of the Strumella disease in the Midwest. Jour. Forestry 32: 614. Brooks, F. T. 1928. Plant diseases, p. 204. Oxford Univ. Press. Humphrey Milford, London. Brown, Nellie A. 1938. The tumor disease of oak and hick- ory trees. Phytopath. 28:401-11. Buckhout, W. A. 1900. The undesirability of red and black oaks because of fungus diseases. Pa. Ag. Exp. Sta. Ann. Rep. 1899: 250-2. Campbell, A. H. 1934. Zone lines in plant tissues II. The black lines formed by Armillaria mellea (Vahl.) Qu(?l. Ann. Appl. Biol. 21:1-22. Carter, J. C. 1936. Cytosporina ludihunda on American efm. Phytopath. 26:805-6. 1938. Fungi associated with oak diseases. Phytopath. 28:4-5. |Abst.] 1940. Diseases of oaks and Verticillium wilt of woody plants. Natl. Shade Tree Conf. Proc. 16:83-91. Cartwright, K. St. G. 1929 A statisfactory method of staining fungal mvcelium in wood sections. Ann. Bot.' 43:412-3. 1937. A reinvestigation into the cause of "brown oak," Fistulina hepatica (Huds.) Fr. Brit. Mycol. Soc. Trans. 21:68-83. Clinton, G. P. 1934. Plant pest handbook tor Connecti- cut II. Diseases and injuries. Conn. Ag. Kxp. Sta. Bui. 358:1-329. Cooke, M. C, and H. W. Harkness 1884. California fungi. GreviUea 13:111-4. Craighead, F. C. 1923. North American cerambycid larvae: Canada Dept. Ag. Bui. 27:90. (New scries, technical.) CrandalI,B. S., Carl Hartley and R. \V. David- son 1937. Wetwood. Phytopath. 27:126. lAbst.] Davidson, Ross W. 1935. Forest pathology notes. U. S. Dept. Ag., PI. Dis. Rep. 19:94-7. Davis, W. H. 1935. A plant disease survey of trees and shrubs in western Massachusetts. U. S. Dept. Ag., PI. Dis. Rep. 19: 260-9. Edson, H. A., and Jessie I. Wood 1936. Diseases of plants in the United States in 1935. U. S. Dept. Ag., PI. Dis. Rep. Sup. 96:115-289. Felt, E. P., and VV. H. Rankin 1932. Insects and diseases of ornamental trees and shrubs, pp. 256-7, 261, 262. The Macmillan Company, New York. Grant, Theodore J., and Perley Spaulding 1939. Avenues of entrance for canker- forming Nectrias of New England hardwoods. Phytopath. 29:351-8. Groom, P. 1915. Brown oak and its origin. Ann. Bot. • 29:393-408. k Guba, E. F. I 1934. SHme flux. Natl. Shade Tree Conf. I Proc. 10:56-60 ' (J Haensler, C. M. '< 1932. Twig blight and canker of the chest- i:,( nut oak. N. J. Ag. Exp. Sta. Dept. Bot. Nursery Dis. Notes 4(12):3--4. !] Harris, Hubert A. 1932. Initial studies of American elm dis- ii eases in Illinois. 111. Nat. Hist. Surv. ' Bui. 20(l):l-70. ;' Hartley, C, and B. S. Crandall 1935. Vascular disease in poplar and | willow. Phytopath. 25:18-9. [Abst.] \ Hartig, R. 1894. The diseases of trees (translated by William Somerville and H. Marshall Ward), pp. 90-6, 99-102, 206-7. Macmillan and Company, London. Heald, F. D. 1914. A little-known disease of chestnut and oak trees. Phytopath. 4:49. lAbst.] 1937. Introduction to plant pathology, pp. . 227-34. McGraw-Hill Book Com- pany, Inc., New York. June 1941 CARTER: OAK DISEASES IN ILLINOIS 229 Heald, F. D., and R. A. Studhalter 1914. The Strumclla disease of oak and chestnut trees. Pa. Dept. Korestrv Bui. 10:1-15. Hennings, P. 1894. Leber das \'orkommen von Bulgaria polymorpha Oeder an lebenden F.i- chen. Ztschr. f. Pflanzenkrank. 4:266. Henry, E. 1902. Note sur quelques nouveaux cham- pignons parasites de chencs. Soc. Bot. de France Bui. 49:151-5. Holtz, W. 1901. Beitrag zur Kenntnis dcr Bauin- fliisse und einieer ihrer Bewohncr. Centbl. r. Bakt. |etc.], .Abt. II, 7: 113-28, 179-89, 229-38, 274-81, 338-50. Home, W. T. 1914. The oak tungus disease ot fruit trees. Cahf. Comm. Hort. Monthlv Bui. 3:275-82. 1915. Oak tungus on .irnii/Zaria mellea in connection with nursery stock. Calit. Comm. Hort. Monthlv Bui. 4:179- 83. 1919. Oak tungus disease, oak-root tungus disease, tungus root rot, toad-stool root rot or mushroom root rot. Calif. Comm. Hort. Monthlv Bui. 8:64-8. Hubert, E. E. 1931. .^n outline of forest pathology, pp. 1 417-22. lohn Wilev and Sons, New I York. Humphrey, H. B., and J. I. Wood 1935. Diseases of plants in the United States in 1933. U. S. Dept. .Ag., PI. Dis. Rep. Sup. 86:107. Ingrain, Delia E. 1912. Preliminary notes on a twig blight ot Qiiercus Priniis. Phvtopath. 12:96. I.Abst.] 1914. .A twig blight o< Quercus Priuiis and related species. Jour. Am. Res. 1 :339-46. Kendall, T. A. ti 1931. Soil aeration used in treatment for I oak-root tungus. Calif. Dept. .Ag. Monthly Buk 20:165-6. Kienholz, R., and C. B. Bidwell 1938. .\ survey ot diseases and detects in 1 Connecticut forests. Conn. |New I Haven] .\ti. Fxp. Sta. Bui. 412:489- I Lefebvre, C. L., and C. O. Johnston 1935. Kansas mvcological notes, 1934. Kan. .Acad.' .Sci. 'Trans. 38:101-3. Ludwig, F. 1886. Leber .Alkoholgahrung und Schleim- fluss lebender Baume. Hedwigia 25: 168-72. 1887. 1st Bulgaria inquinans ein Wund Parasit? Centbl. f. Bakt. u. Para- si tenkunde 2:521. 1888. Der braune Schleimfluss. Centbl. f. Bakt. u. Parasitenkunde 4:323-4. Massee, George 1907. New and additional species of tungi. Second series. Kew Bui. 238-44. 1910. Diseases of cultivated plants and trees, pp. 183, 210, 250. Duckworth and Company, London. McKenzie, Malcolm A. 1937. Tree diseases in Massachusetts. U. S. Dept. Ag., PI. Dis. Rep. 21: 55-8. Moreillon, M. 1918 Diaporlhe laleola, an ascomycete injurious to oaks. |.-\bst. in Inter- natl. Inst. .Ag. iRomei], Internatl. Rev. Sci. and Pract. Ag. 9(3i:397-8. Newman, R. 1926. Oak t'ungus situation. Pacific Rural Press 111:6. Ogilvie, L. 1924. Observations on the "slime fluxes" of trees. Brit. Mvcol. Soc. Trans. 9:167-82. Orton, W. A. 1908. Plant diseases in the L'nited States in 1907. L'. .S. Dept. Ag. Vrbk. 1907: Overholts, L. O. 1934 Mycological notes for 1933. My- cologia 26:506. Owens, C. E. 1928. Principles of plant pathology, pp. 446-52. John Wilev and Sons, New York. Rankin, W. H. 1914. Sphaeropsis canker of Quercus Pri- nus. Phytopath. 4:44-5. |Abst.] 1927. Manual of tree diseases, pp. 78-82, 244-6. The Macmillan Companv, New York. Ruhland, W. 1904. Fin neuer, verderblicher Schadling der Eiche. Centbl. f. Bakt. |etc.f, Abt. II, 12:250-3. Saccardo, P. A. 1884. Sylloge tungorum omnium hucus- que cognitorum. Patavii, sumptibus auctoris. 3:96, 240, 248. 1892 Sylloge tungorum omnium hucus- que cognitorum. Patavii, sumptibus auctoris. 10:161. 1899 Sylloge tungorum omnium hucus- 230 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Vol. 21, Art. 6 que cognitorum. Patavii, sumptibus auctoris. 14:913, 924. 1913. Sylloge tungorum omnium hucus- que cognitorum. Patavii, sumptibus auctoris. 22:1142. Sleeth, B., and C. B. Bidwell 1937. Polyporus hispidus and a canker of oaks. Jour. Forestry 35:778-85. Spaulding, P., T. J. Grant and T. T. Ayers 1936. Investigations of Nectria diseases in hardwoods of New England. Jour. Forestry 34:169-79. Taubenhaus, J. J. 1934. Live oak disease at Austin. Tex. Ag. Exp. Sta. Ann. Rep. 1934:97-8. 1935. Live oak disease at Austin. Tex. Ag. Exp. Sta. Ann. Rep. 1935: 99-100. Taubenhaus, J. J., and W. N. Ezekiel 1932. Citv tree diseases at Fort Worth. Tex. Ag. Exp. Sta. Ann. Rep. 1932: 76. Tehon, L. R., and W. R. Jacks 1933. Smooth patch, a bark lesion of white oak. Jour. Forestry 31:430-3. Thomas, Harold E. 1934. Studies on .-Irmillaria mellea (Vahl.) Quel, infection, parasitism and host resistance. Jour. Ag. Res. 48:187- 218. Tubeuf, K. von, and W. G. Smith 1897. Diseases of plants induced by cryp- togamic parasites, pp. 142, 144. Longmans, Green and Company, New York. Ward, H. Marshall 1901. Diseases in plants, p. 233. Mac- millan and Company, London. Waterman, Alma M. 1939. Diseases of shade and ornamental trees. U. S. Dept. Ag., PI. Dis. Rep. 23:85-7. Wehmeyer, L. E. 1926. Cultural life histories of Melanconis and Pseudonalsa. Mycologia 18: 257-73. Weir, J. R. 1925. Notes on the parasitism of Endothiti gyrosa (Schw.) Fr. Phytopath. 15: 489-91. Welch, D. S. 1934a. Nectria canker on hardwoods in northeastern United States. U. S. Dept. Ag., PI. Dis. Rep. 18:21-2. 1934b. The range and importance of Nec- tria canker on hardwoods in the Northwest. Jour. Forestry 32:997- 1,002. White, R. P. 1936. Notes on new or unusual outbreaks of diseases of ornamentals in New Jersey in 1935. U. S. Dept. Ag., PI. Dis. Rep. 20:79-81. Zeller, S. M., and C. E. Owens 1922. European canker in Pacific Coast states. Phytopath. 12:105.