Brown Root Rot of Trees Caused by Phellinus Noxius in Windbreaks on Ishigaki Island, Japan -Incidence of Disease , Pathogen and Artificial Inoculation

日植病報61: 425-433 (1995) Ann. Phytopathol. Soc. Jpn. 61: 425-433 (1995)

Brown Root Rot of Trees Caused by Phellinus noxius in Windbreaks on Ishigaki Island, Japan -Incidence of Disease , Pathogen and Artificial Inoculation-

Yasuhisa ABE*, Takao KOBAYASHI**, Masatoshi ONUKI***, Tsutomu HATTORI•õ and Masaichi TSURUMACHI***

Abstract

Extensive wilts of trees have recently occurred in the windbreaks at Okinawa Branch of the Tropical Agricultural Research Center in Ishigaki Island, Okinawa, Japan. Dead or declined trees were observed at 43 points, the total number of dead and declined trees was over 200 and total length of damaged windbreaks was 515m, in about 11% of the total length of windbreaks. Roots of dead and declined trees were collected and many fungus cultures were isolated from them. Most isolates had the following common cultural characteristics: no clamp connections on septa, staghorn-like hyphae and arthroconidia. Two cultures isolated from tissue of diseased trees were artificially inoculated into saplings of Podocarpus macrophyllus. Nine saplings were killed out of 19 inoculated saplings within 13 months and the fungus was reisolated from the dead saplings. As the isolates were considered to be a hymenomycetous fungus, fungal fruiting bodies were collected from windbreaks and from nearby and cultures were isolated from the collected fruiting bodies. One of cultures isolated from the collected fruiting bodies coincided in cultural characteristics with the isolates from dead and declined trees. The fruiting body from which this culture was isolated, was identified as Phellinus noxius (Corner) Cunningham. Taxonomic study revealed that Ph. sublamaenis (Lloyd) Ryvarden, published as a prior name for Ph. noxius, is a synonym of Ph. lamaensis. The fungus reported as Ph. lamaensis by Yasuda from Bonin Island of Japan in 1916, was identified as Ph. noxius. (Received January 1995; Accepted May 15, 1995)

Key words: brown root rot, Phellinus noxius, Phellinus sublamaensis, root and butt rot, windbreak, wood decay.

orientalis. In addition, Hibiscus rosa-sinensis is planted in INTRODUCTION the outermost part of windbreaks as ornamental trees. There is also a plantation of Pinus luchuensis in the In Okinawa Prefecture, plantations of windbreaks windbreaks. have been encouraged for protection of cultivated land, Wilt of one tree was first found in the windbreaks at especially for sugar cane cultivation. The windbreaks at the Okinawa Branch of TARC in 1983 or 1984 and the the Okinawa Branch of the Tropical Agriculture Re- number of dead and declined trees increased year by search Center (TARC)*1 in Ishigaki Island were estab- year. Surveys were made to find the cause of the wilts in lished as a model of plantations in 1975. Main tree 1988. A preliminary survey suggested that the wilts were species included Casuarina equisetifolia, Calophyllum caused by a fungus not reported previously from Japan, inophyllum, Podocarpus macrophyllus, Garcinia subel- characterized by a quick decline of trees and the forma- liptica, Delonix regia and Erythrina variegata var. tion of dark-brown mycelial mats on the surface of the

＊Shikoku Research Center , Forestry and Forest Products Research Institute (FFPRI), 915, Asakura-Tei, Kochi 780, Japan

森林総合研究所四国支所＊＊Forest Development Technological Institute , 7, Rokuban-cho, Chiyoda-ku, Tokyo 102, Japan (Formerly at FFPRI, Ibaraki)林業科学技術振興所＊＊＊Kyushu National Agricultural Experiment Station , 2421, Suya, Nishigoushi, Kikuchi-gun, Kumamoto 861-11, Japan

(Formerly at Okinawa Branch of Tropical Agriculture Research Center)九州農業試験場 †FFPRI ,1, Matsunosato, Kukizaki, Inashiki-gun, Ibaraki 305, Japan森林総合研究所 *1The institute was reorganized into Japan International Research Center for Agricultural Sciences (JIRCAS)in October

1993. Okinawa Branch also changed its name to Okinawa Sub-tropical Station of JIRCAS. 426 日本植物病理学会報第61巻第5号平成7年10月

roots of dead trees. The roots of diseased or dead trees U.S.A (BPI), were also examined for a comparative were dug up and cultures isolated from them. Some of study with the collected fruiting bodies. the diseased roots were sent to Forestry and Forest Inoculation. Five-years old saplings of P. macro-

Products Research Institute (FFPRI) and isolation of phyllus, 1 to 1.2m high and about 1.5cm in diameter at fungi also made there. The pathogen was finally identifi- the base, were used for an inoculation study. Each ed by a comparative study on cultures and specimens, sapling was planted in an unglazed pot one month before and its pathogenicity was confirmed by artificial inocula- inoculation. Two cultures isolated from tissue of dis- tion. Cultural characteristics and wood-decaying ability eased trees (WD-190, 191) were used for inoculations. of the causal fungus were also studied. Cultures were grown in sawdust medium (70g of beech The objective of this study were 1) to investigate the sawdust, 20g of rice bran, 120g of water) in plastic incidence of the disease of windbreaks at the Okinawa bottles at 30℃ for 30 days. Approximately 50g of fungal Branch of TARC, 2) to determine the pathogen of the mycelia with sawdust medium was used as inoculum, disease, and 3) to evaluate the pathogenicity and other which was placed on lateral roots and covered with soil characteristics of the pathogen. A part of this study has in each pot. Small lateral roots were cut and inoculum been reported preliminarily elsewhere2,12). was placed on them in injuring treatment. Controls were inoculated only with sawdust medium. Inoculation was

MATERIALS AND METHODS performed on 26 July, 1989. Inoculated saplings were placed in the half-shade in the yard of FFPRI and were Field survey. Field surveys were made in observed till the end of 1990. Isolation was made from November to December in 1988. Species and number of roots and stems of dead saplings by taking small pieces dead and declined trees were recorded and their loca- of tissue. The pieces were treated with 70% ethanol, tions were plotted on a map. Forest gaps produced by 0.1% HgCl2 and sterilized water, then placed on PDA dead and declined of trees were recorded by measuring slants and incubated at 25℃ for several days. the maximum distance between wilting trees at opposite Cultural characteristics and wood-decay abil- sides of each affected site. As the damages of the ities. Cultures isolated from tissue of diseased trees windbreaks were suspected to be caused by a wood-de- were grown on PDA plates and their cultural character- caying fungus, fungal fruiting bodies on dead trees or istics were studied and assigned to the key patterns by decayed stumps were collected from the windbreaks of Nobles15) and Stalpers21). The effect of temperature on Okinawa Branch and adjacent area. mycelial growth was studied for two isolates (WD-190, Isolation and identification. For isolation of 191) using 9-cm diameter petri dishes containing 20ml cultures, small pieces of tissue were cut out from sap PDA. The agar was placed centrally with 5-mm diam. wood and inner bark in roots of diseased or dead trees. plug cut from the colony of the test fungus on PDA Isolation was performed by two methods. In one method, plate. Inoculated plates were incubated at temperatures cut pieces of tissue were rinsed in running tap water for from 4℃ to 40℃ at intervals of 3℃ with five replicates two hours, placed on potato-dextrose agar (PDA) medi- for each temperature. Colony size was measured along um in petri dishes and incubated at 15•Ž for two weeks. two diameters at right angles every 2 days and growth In the other method, pieces of tissue were soaked in 70% of mycelium radius was calculated. ethanol for a few seconds, treated with 0.1% HgCl2 for Wood blocks of Calophyllum vexans, Casuarina glauca, a few minutes, rinsed in sterilized water, then placed on Fagus crenata, P. macrophyllus, and Quercus acutissima, PDA slants and incubated at 25•Ž for a few days. 15×15×20mm in size, were used for wood-decay test.

Hyphae growing from these pieces were transferred to Wood blocks were numbered and dried in a circulating- PDA medium in petri dishes, incubated at 25•Ž for air drying oven at 60℃ for 48hr, then cooled in a several days to a few weeks and hyphal characteristics desiccator and weighed. Sawdust medium was prepared were examined with a microscope. by mixing 70g of beech sawdust and 20g of rice bran Cultures were also isolated from fungal fruiting and 120g of water in a plastic bottle of 850-ml content. bodies collected on dead trees and decayed stumps. Five wood blocks were buried flush with the surface of

Small pieces of tissue were taken from inner part of sawdust medium in each bottle and the bottles were fruiting bodies, placed on PDA slants with or without 5 autoclaved at 120℃ for 1hr. Two isolates from tissue of ppm benomyl and incubated at 25•Ž. Cultural character- diseased trees (WD-190, 191) and one isolate of Coriolus istics were compared between the isolates obtained from versicolor (L.: Fr.) Quel. (WD-876=Rinshi 1030 in JIS Z diseased or dead roots and those from fungal fruiting 2119) were inoculated into each bottle, which was in- bodies. cubated at 30℃ for 6 months. Wood blocks of Fa. Collected fruiting bodies of fungi were examined with crenata and Q. acutissima inoculated with the same a microscope and morphological characteristics were isolates were incubated at 25℃ for 6 months. After recorded. Specimens of Fomes noxius and related incubation, wood blocks were taken out from bottles, species from the herbaria of the National Science dried as described above and dry weight was measured. Museum in Tokyo (TNS), the Singapore Botanic Gar- Percentage of weight loss was determined as the aver- dens (SING) and the National Fungus Collections in age of 5 wood blocks. Ann. Phytopathol. Soc. Jpn. 61 (5). October, 1995 427

with mycelial mat, foliage turns reddish brown (in P. RESULTS macrophyllus and Cs. equisetifolia) or yellowish brown (in Cl. inophyllum and G. subelliptica), and then the tree Field survey wilts and finally dies. The disease is characterized by the An outline of the windbreaks and locations of dead formation of violet-brown to dark-brown mycelial mat and declined trees are shown in Fig. 1. The cultivated on the surface of diseased roots (Plate I-2). The mycelial land is surrounded by windbreaks of 550m square and 9 mat often becomes black and thick when contaminated to 31m wide, and the inner part of the land is partitioned with exuded resin, soil or sand. It grows around the by windbreaks 2 to 5m wide. Dead or declined trees trunk up to 30cm above the ground level. White pocket were observed at 43 points in the windbreaks, as indicat- rots or mottled rots are observed in sap wood near the ed in Fig. 1. The total length of damaged windbreaks base and in roots. A network of brown lines is formed in was 515m, 11.2% of the total length of windbreaks (4617 decayed wood in an advanced stage of the disease (Plate m). Species and numbers of dead or declined trees are I-4). Infected trees are easily uprooted or blown down listed in Table 1. Most dead and declined trees were Cs. by strong wind breaking at the base. Occasionally equisetifolia 86 (41% of all 211 dead and declined trees) basidiocarps are formed on decayed stumps or uprooted and Cl. inophyllum 70 (33%). H. rosa-sinensis located in trees (Plate I-5). the outermost parts of windbreaks were also affected, Isolation and identification while no dead or declined trees were observed in planta- Most cultures isolated from roots of diseased or dead tions of Pinus luchuensis, although two trees suffered trees had common cultural characteristics. Cultures from pitch canker caused by Fusarium moniliforme var. with these common cultural characteristics were iso- subglutinans. lated from all species of dead or diseased trees. On the Symptoms other hand, several cultures were isolated from fruiting When a tree is affected, foliage fades (in Cs. equiseti- bodies of wood-decay fungi collected from the wind- folia) or turns yellowish green (in Cl. inophyllum) and breaks and adjacent areas. One culture isolated from remain undersized. When a trunk or main root is girdled these fruiting bodies had the same cultural characteris-

Fig. 1. Distribution of trees affected by Phellinus noxius in windbreaks at the Okinawa Branch of Tropical

Agriculture Research Center (November, 1988). •E: a point where the disease broke out. Numbers indicate the

number of locations listed in Table 1. Letters indicate tree species that compose windbreaks. a: Casuarina

equisetifolia, b: Calophyllum inophyllum, c: Podocarpus macrophyllus, d: Delonix regia, e: Garcinia subelliptica,

f: Erythrina variegata var. orientalis, g: Bauhinia racemosa, h: Pinus luchuensis, i: Hibiscus rosa-sinensis. 428 日本植物病理学会報第61巻第5号平成7年10月 tics as those from roots of affected trees. The fungal mens of SING, the fungus was identified as Phellinus fruiting body, from which the corresponding culture was noxius (Corner) Cunningham. isolated, is brown and resupinate and has pores in The following Ph. noxius cultures were isolated from hymenium (Plate I-5). The morphological characteristics roots of affected trees or a fungal fruiting body that had of the fruiting body suggest that the fungus belongs to been collected at Ishigaki, Okinawa Pref. in November the genus Phellinus Quelet in the Hymenochaetaceae, 1988. They are preserved in FFPRI and in the Genetic Aphyllophorales. By a comparative study with speci- Resource Center, National Institute of Agrobiological

Table 1. Dead and declined trees of windbreaks at Okinawa Branch of Tropical Agriculture Research Center (Novem- ber, 1988)

a) A: Casuarina equisetifolia, B: Calophyllum inophyllum, C: Podocarpus macrophyllus, D: Delonix regia, E: Garcinia subelliptica, F: Erythrina variegata var. orientalis, G: Bauhinia racemosa. b) Only stumps were left. Ann. Phytopathol. Soc. Jpn. 61 (5). October, 1995 429

Resources, Ministry of Agriculture, Forestry and Fish- septate, 3-10ƒÊm wide; skeletal (setal) hyphae pale eries (MAFF). brown to dark brown, thick-walled, 6-23ƒÊm wide. Setal Phellius noxius cultures: MAFF-410464, isolated from hyphae abundant in hymenium, reddish to dark brown, bark tissue (BT) of Cl. inophyllum, by Takao Kobayashi 7.5-25ƒÊm wide, with obtuse end. No setae in hymenium. (K); MAFF-410465, isolated from BT of Cs. equisetifolia, Basidiospores and basidia not observed. For more infor- by K; MAFF-410467, isolated from BT of G. subelliptica, mation, see other literature6,8,18). by K; MAFF-410468, isolated from BT of P. macrophyl- Taxonomy of Ph. noxius and related species lus, by K; MAFF-410469, by K; MAFF-410470, isolated The fungus reported by Yasuda22) as Ph. lamaensis from BT of Bauhinia racemosa, by K; WD-190, isolated from Bonin Isl. was identified as Ph. noxius by examina- from Cl. inophyllum, by Y. Abe & Tadashi Kobayashi tion of the specimen preserved at TNS. The type speci- (AK); WD-191, isolated from Cs. equisetifolia,by AK; WD- men of Ph. sublamaensis (Lloyd) Ryvarden has setae in 192, isolated from fungal tissue of Ph. noxius, by AK. hymenium and has narrower setal hyphae than Ph. Description of the fungus noxius. As these characteristics are just same as those of Phellinus noxius (Corner) Cunningham, N.Z. Dep. Sci. Ph. lamaensis, Ph. sublamaensis is confirmed to be a Industr. Res. Bull. 164: 221, 1965; Fomes noxius Corner, synonym of Ph. lamaensis, as indicated below. Gard. Bull. Straits Settlem. 5 (12): 342-345, 1932. Phellinus lamaensis (Murr.) Heim, Ann. Crypt. Exot. 7 Basidiocarp perennial, resupinate to effused-reflexed, (1): 21-22, 1934. 2.5-15cm or more wide, 2.5-20cm long, woody to corky. =Fomes sublamaensis Lloyd , Mycol. Writ. 7: 1128, Pileus up to 7cm broad and up to 3.3cm thick; upper 1922; Phellinus sublamaensis (Lloyd) Ryvarden, surface brown to dark brown; margin of pileus brown- Mycotaxon 35: 235, 1989. ish yellow to dark brown. Pore surface black when Phellinus lamaensis specimens examined: F. sub- fresh, brown to dark brown when dried; pores 7-10 per lamaensis Lloyd, TYPE, US 0310585, Nov. 1920, Coll. mm; tubes 1-10mm long. Context brownish yellow to O.A. Reinking, Mt. Maquiling, Luzon, Philippines (BPl); light brown, black zone lines present in the surface layer Fomes lamaensis, No.14589, Sumatra, Indonesia of pileus and in inner tissue, faint concentric zonation (SING); F. lamaensis, No.26070, Kelanton, Malaysia often present; hyphal system dimitic: generative (SING); F. lamaensis, No.24488, Pahang, Malaysia hyphae thin-walled, hyaline to pale brown, simple- (SING); F. lamaensis, No.9462, Johor, Malaysia (SING); F. lamaensis, No.23168, Raffles College, Sin- gapore (SING); F. lamaensis, No.9510, Johor, Malaysia Table 2. Results of artificial inoculation of Phellinus (SING); F. lamaensis, No.50132, Mt. Maquiling, Luzon, noxius into saplings of Podocarpus macrophyl- Philippines (SING); F. lamaensis, No.5878, Singapore lus (13 months after inoculation) (SING); F. lamaensis, No.19192, Bettotan near Sanda- kan, Malaysia (SING); F. lamaensis, No.10950, Johor, Malaysia (SING). Phellinus noxius specimens examined: F. noxius, No. 23741, Negri Sembilan, Malaysia (SING); F. noxius, No. 23168, Raffles College, Singapore (SING); F. noxius,

071313, Kuala Lumpur, Malaysia (SING); F. noxius, 071314, Kuala Lumpur, Malaysia (SING); F. noxius, 071321, Malay Penninsula, Malaysia (SING); F. noxius,

Fig. 2. Hyphal characteristics of Phellinus noxius in culture. A: Staghorn-like hyphae. B: Arthroconidia. 430 日本植物病理学会報第61巻第5号平成7年10月

TFM-F-14979, Nov. 1988, Coll. T. Kobayashi, Ishigaki 25, (28), 30, (31), 34, 35, 38, 48, (50), 52, 53, 54, (55), 61, 64, Isl., Okinawa, Japan (TFM); F. lamaensis, No.202544, 67, 80, 84, 89 for the system of Stalpers21). Table 3 shows Oct. 6, 1915, Bonin Isl., Japan (TNS); F. noxius, No. the relation between temperature and mycelial growth 208005, June 30, 1937, Yamamoto, Taiwan (TNS). of Ph. noxius. Mycelial growth occurred at temperatures Inoculation between 13 and 37•Ž in both isolates. Maximum mycelial

Phellinus noxius was proved to be pathogenic to P. growth-rate was 11.3mm/day at 31•Ž in WD-190 and 14. macrophyllus, since it caused wilts of saplings with root 5mm/day at 28•Ž in WD-191. inoculations. The first symptom is fading of foliage and Results of wood decay experiments are shown in saplings were killed within a month after fading had Table 4. Phellinus noxius caused weight losses in all taken place. Four saplings were killed in November of wood blocks, but weight losses were relatively small, 1989 and 5 saplings in 1990 (2 in March, 1 in April and 2 ranging 2.3% to 17.1%. In beech wood blocks, Coriolus in August, Plate I-3). A total of 9 saplings were killed out versicolor caused great weight losses (37.7% at 30•Ž and of 19 inoculated saplings and control trees were all alive 54.6% at 25•Ž), but Ph. noxius caused small weight losses in the end of 1990 (Table 2). Six were killed out of 7 (4.4 to 10.9%). On the contrary, C. versicolor did not saplings inoculated with WD-191, but only 3 out of 12 cause weight loss in wood blocks of Cl. vexans and of P. saplings inoculated with WD-190. Eight saplings out of macrophyllus, but Ph. noxius caused weight losses of 2.3 14 were killed when inoculated without injuring treat- to 5.1% in the former wood blocks and 5.0 to 9.0% in the ment. Dark-brown mycelial mats were formed on the latter. The isolate of WD-190 always caused greater surface of diseased roots (Plate I-7) and brown zone lines weight losses than WD-191. appeared in wood of lower part of stems (Plate I-8) in dead saplings. Phellinus noxius was reisolated on PDA DISCUSSION from diseased roots and lower parts of stems (up to 20 cm above the ground) in 8 dead saplings. Phellinus noxius caused brown root rot of forest trees, Cultural characteristics and wood-decay abil- like rubber trees, tea bushes and oil palms6,14). The ities fungus is widespread among tropical countries in South- The colonies of Ph. noxius are white at first, later east Asia, Oceania and Africa1,6,8,14,16). In Japan, Ph. become light brown to reddish brown, cottony to felty, noxius has been found in Iriomote Isl., Miyako Isl., the or woolly (Plate I-6). Hyphae are simple septate, hyaline main Isl. of Okinawa and Bonin Isl. besides Ishigaki to brown and 1.5-10ƒÊm wide. Brown staghorn-like Isl.9-13,22) Brown root rot has also been reported from hyphae and arthroconidia are produced in cultures on Taiwan5,20) which is close to these islands.

PDA medium (Fig. 2). Arthroconidia are hyaline, 3-40 This fungus was first described by Corner6) as F. ƒÊm long, 1.5-7ƒÊm wide. Key patterns of the cultures noxius Corner and later transferred to the genus Phel- were: 2, 6, 11, 35, 37, 39, 41, 42, 54 for the system of linus by Cunningham7). Phellinus noxius and Ph. lamaen- Nobles15); 1, (2), 3, 5, (6), 12, (13), 14, (15), (17), (19), 21, 22, sis are closely related, but Ph, noxius is characteristic in having wide setal hyphae and no setae in hymenium, and in being a facultative parasite6,8,18). Ryvarden17) reported Table 3. Effect of temperature on mycelial growth of Ph. sublamaensis (Lloyd) Ryvarden is a prior name for Phellinus noxius: average radial growth of Ph. noxius, but two species were proved to be different in hyphae (mm/day) the present study. The type specimen of Ph. sublamaensis has setae and narrower setal hyphae (5-8ƒÊm wide) in hymenium. On the contrary, the examined specimens of Ph. noxius have no setae, but have wider setal hyphae

(7-25ƒÊm wide) in hymenium. Phellinus sublamaensis (Lloyd) Ryvarden (F. sublamaensis Lloyd) is a synonym

Table 4. Weight losses of wood blocks decayed by Phellinus noxius and Coriolus versicolor for 6 months

a) Standard error. Ann. Phytopathol. Soc. Jpn. 61 (5). October, 1995 431

of Ph. lamaensis (Murr.) Heim, as already indicated by Ryvarden and Johansen18). For this reason, we use the name •gPhellinus noxius•h for the causal fungus. In Japan, Yasuda22) reported a fungus collected from Bonin Island as F. lamaensis and gave a Japanese name •g Shima-saruno-koshikake•h for it. The present fungus coincides with Yasuda's specimen preserved at TNS in morphological characters of fruitbodies. It means Yasuda's report is the first record of Ph. noxius from

Japan, but he did not mention a disease by the fungus. Later Sawada19,20) studied the wilt of Cinnamomum camphora and other trees caused by F. noxius in Taiwan

and gave a Japanese name •gKikoroshi-saruno-koshikake•h for the causal fungus. Sawada's report is the first

one on the brown root rot published by a Japanese scientist, but the earlier Japanese name •gShima-saruno- koshikake•h by Yasuda22) was accepted for the causal fungus, as already reported elsewhere2). •gMinamine-

gusare-byo•h was proposed as a Japanese name for the disease of P. macrophyllus2), since Sawada19,20) did not

give Japanese name for the disease. Not only P. macrophyllus, but also many other tree species were affected by the disease, as described in this paper and in other literature5,8,10,16). Phellinus noxius belongs to the family Hymenochaeta- ceae and its hyphae have no clamp connections on septa. The fungus characteristically produces brown staghorn- like hyphae and arthroconidia in culture. Cultural characteristics of Ph. noxius have been studied by several scientists3-5,21). Bakshi et al.3) made no mention of arthroconidia. Stalpers21) reported that one strain of Ph. noxius (CBS 170.32) produced arthroconidia in culture, but he treated the strain as Phellinus sp. instead of Ph. noxius. Later Bolland4) and Chang5) studied cultural characteristics of Ph. noxius and they reported the

presence of arthroconidia in culture. The presence of arthroconidia appeared to be an important cultural characteristic for Ph. noxius. Phellinus noxius has wood-decaying ability, while this ability is not as strong as in C. versicolor (a designated isolate in the method of test for decay of wood in JIS, 1977) for woods of Fa. crenata and Q. acutissima which are temperate tree species. However, Ph. noxius in most cases caused greater weight losses than C. versicolor in woods of Calophyllum, Casuarina and Podocarpus species which are subtropical. Wood-decaying abilities and optimum temperature for decaying woods were different, depending on isolates of Ph. noxius. More studies should be done on variation of wood-decaying abilities in relation to their pathogenicities for the fun-

gus. Anyway, the wood-decay ability in Ph. noxius sup- ports a view that the fungus is a facultative parasite, as pointed out by Corner6). Results of the inoculation experiment indicate Ph. noxius is highly pathogenic, enough so to invade roots without injury. As infection of Ph. noxius occurs only when a root of a healthy host directly contacts a diseased stump or root14), the fungus must have infected 432 日本植物病理学会報第61巻第5号平成7年10月

Plate I Ann. Phytopathol. Soc. Jpn. 61 (5). October, 1995 433

Plant Pathol. Bull. 1: 90-95. 19. Sawada, K. (1928). Notes on the dieback of camphor 6. Corner, E.J.H. (1932). The identification of the brown- trees. Taiwan Sanrin Kaihou 30: 26-36 (in Japanese). root fungus. Gardens' Bulletin Straits Settlem. 5: 317- 20. Sawada, K. (1934). Materials of the Formosan fungi 350. (32). Trans. Natl. His. Soc. Formosa. 24: 450-464 (in 7. Cunningham, G.H. (1965). Polyporaceae of New Japanese). Zealand. N.Z. Dep. Sci. Industr. Res. Bull. 164: 221-222. 21. Stalpers, J.A. (1978). Identification of wood-inhabiting 8. Fidalgo, O. (1968). Phellinus pachyphloeus and its allies. Aphyllophorales in pure culture. Stud. Mycol. 16, Mem. New York Bot. Gard. 17: 109-147. Centraalb. Schimmelcult., Baarn, pp. 199-217. 9. Kawabe, Y. Kobayashi, T., Usugi, T. and Tsurumachi, 22. Yasuda, A. (1916). Miscellaneous notes of fungi (56). M. (1990). Research on damages in windbreaks of Bot. Mag. Tokyo 30: 350 (in Japanese). Casuarina equisetifolia caused by brown root rot. Ann. Phytopathol. Soc. Jpn. 56: 387 (Abstr. in Japanese). 和文摘要 10. Kawabe, Y., Kobayashi, T. and Usugi, T. (1993). Brown root rot of woody plants caused by Phellinus 阿部恭久・小林享夫・大貫正俊・服部力・鶴町昌市:石垣 noxius in Okinawa Prefecture. Forest Pests 42: 176-179 島の耕地防風林に発生したシマサルノコシカケによる樹木の南 (in Japanese). 根腐病-被害実態,病原菌および接種試験- 11. Kobayashi, T., Abe, Y. and Kawabe, Y. (1991). Brown 沖縄県石垣島の熱帯農業センター沖縄支所(現:国際農林水 root rot. A new menace that occurred in windbreaks in 産業研究センター沖縄支所)の耕地防風林にイヌマキ,モクマオ Okinawa Prefecture. Ringyo to Yakuzai 118: 1-6 (in ウ,テリハボク等の樹木の萎凋・枯損被害が発生した。1988年 Japanese). 11～12月に現地調査を行った結果,枯損・萎凋は43地点で発生 12. Kobayashi, T., Onuki, M., Tsurumachi, M., Kobayashi, し,枯損・萎凋木の総計は211本,被害部分の延べ長は515mで, T. and Abe, Y. (1989). Survey on the cause of decline of 防風林の総延長の11.2%を占めていた。被害木の根株を掘り起 windbreaks in Ishigaki Island. Ann. Phytopathol. Soc. こし菌株の分離培養を行うと,ほとんどの被害木から同一の培 Jpn. 55: 490 (Abstr. in Japanese). 養的性質を有する菌株が分離された。本菌をイヌマキ苗木の根 13. Kobayashi, T. and Kawabe, Y. (1992). Tree diseases に接種すると19本中9本が13ヵ月以内に枯死し,枯死した苗 and their causal fungi in Miyako Island. Jpn. J. Trop. 木からは本菌が再分離された。培養的性質から本菌が菌蕈類に Agric. 36: 195-206. 属することが推定されたので,防風林内外の枯損木・伐根上に発 14. Nandris, D., Nicole, M. and Geiger, J.P. (1987). Root 生していた菌蕈類の子実体から菌株を分離培養した。それらの rot diseases of rubber trees. Plant Dis. 71: 298-306. 子実体の一つから分離された菌株の性質が,被害木から分離さ 15. Nobles, M.K. (1965). Identification of cultures of wood- れた菌株の性質と一致し,その子実体はPhellinus noxiusと同 inhabiting Hymenomycetes. Can. J. Bot. 43: 1097-1139. 定された。一方,安田が1916年に小笠原からFomes lamaensis 16. Pegler, D.N. and Waterston, J.M. (1968). Phellinus (シマサルノコシカケ)として報告した菌は,Ph. noxiusである noxius. CMI Descr. Path. Fungi Bact. no. 195: 2p. ことが判明した。沢田は1934年にPh. noxiusを「キコロシサル 17. Ryvarden, L. (1989). Type studies in the Polyporaceae- ノコシカケ」として台湾から報告しているが,安田の命名が早い 21. Species described by C.G. Lloyd in Cyclomyces, ので病原菌の和名は「シマサルノコシカケ」を採用し,病名とし Daedalea, Favolus, Fomes and Hexagonia. Mycotaxon て「南根腐病」を提案した。また,Ph. noxiusよりも先名権が 35: 229-236. あるとされていた種Ph. sublamaensisの基準標本を検討した結 18. Ryvarden, L. and Johansen, I. (1980). A preliminary 果,その標本はPh. lamaensisであることが判明したため,病原 polypore flora of East Africa. Fungiflora, Oslo, pp. 178- 菌の学名としてはPhellinus noxiusを採用する。 191.

Explanation of plate

Plate I

1. Dead and dying trees in a windbreak. At Okinawa Branch of the Tropical Agriculture Research Center.

2. Basal part of a infested tree (Calophyllum inophyllum) in a windbreak. Arrow indicates dark-brown mycelial mat

formed on the root surface.

3. Saplings of Podocarpus macrophyllus inoculated with Phellinus noxius (4 months after inoculation). Left two living

saplings are control and right two dead were inoculated with Ph. noxius.

4. Brown zone lines formed by Ph. noxius in wood.

5. Fruitbody of Ph. noxius formed on decayed stump. Arrow indicates pore surface.

6. Culture of Ph. noxius grown on PDA (incubated at 25•Ž for 10 days).

7. Roots of a sapling of P. macrophyllus inoculated with Ph. noxius (13 months after inoculation). Arrow indicates

dark-brown mycelial mat formed on the surface of roots and basal part of a stem.

8. Cross section of basal part of a stem in a sapling of P. macrophyllus inoculated with Ph. noxius (9 months after

inoculation). Arrow indicates brown zone lines.