日林 誌 68(4)'86 161～164

短 報 Needle Blight of pensilis*

Takao KOBAYASHI**

BAYASHI, 1980; ZINNO, 1969). I. Introduction III. Morphology In September 1980, a needle blight was observed on seedlings of K. KOCH, a Stroma acicola and ramicola, amphigenous on Chinese of the family , at the needles, scattered, composed of pseudoparenchyma Asakawa Experimental Forest of the Forestry and tous cells, olive brown to dark greenish-brown, Forest Products Research Institute, Hachioji, To 45.65ƒÊm in diameter; conidiophores brown to ol kyo, Japan. Originally, of G. pensilis were ive brown, paler toward the top, simple, flexuous introduced from . They were grown in the or zigzag shape, non or 1-septate, 32•`98•~3.5•`5 nursery for two years, and the seedlings were ƒÊ m; conidia pale olive-brown to olive brown or planted in the field in 1978. Many fruiting bodies, greenish brown, obclavate, straight, or slightly dark green sooty masses, were observed on the curved, 3•`9-septate, constricted at septa in aged blighted needles and on the diseased green shoots. stage, 35.65•~5•`6.5 ƒÊm, with many minute warts Microscopic examination showed them to be the co on the surface (Fig. 1). nidial masses of a species of Cercospora. Morpho Conidia of the fungus have two noticeable fea logical characteristics of this species seem to be sim tures, one being the marked constriction and dark ilar to those of C. sequoiae ELLIS et EVERHART color in the aged stage, and the other being the causing the needle blight of japonica ornamentation of their surface with many warts

D. DON. The purpose of the study reported here (Fig. 1 b). In the Cercospora, a few spe was to confirm the similarity of the two species of cies have warted and dark-colored conidia. C. Cercospora causing the needle blights of G. pensilis sequoiae is the only species on having dark

and of C. japonica. conidia with many warts. It is known to cause the needle blight of Cryptomeria japonica, II. Symptoms and Signs distichum, and gigantea (LINDL.) DEENE in

Small reddish-brown spots appear on the needles Japan (ITO et al., 1952, 1958; ZINNO, 1969). Mor

and green shoots. Those on needles soon extend phologically, the Cercospora sp. on G. pensilis was their entire length and blighted needles soon fall. identical with C. sequoiae as shown in Figures 1, 2, Circular spots on green shoots and stems enlarge and Table 1. longitudinally and horizontally. Some of them co alesce with each other and finally girdle the stem or IV. Pathogenicity shoot resulting in death of the part above the le Monoconidial isolation of the fungus produced sion. Severely infected seedlings lose almost all of similar colonies to those of Cercospora sequoiae iso their needles, and many branchlets are killed by the lated from Cryptomeria japonica. They were dark spread of the lesions. About a half of the green to blackish green and were covered with gray lings planted had been killed by the disease in the ish white aerial mycelia. They did not produce two years after planting. In the case of survivors, any conidia on agar media in an ordinary procedure. new needles sprouted from adventitious buds formed Therefore, mycelial suspensions were used for in on bare stems and branchlets. They are again ocula in two inoculation experiments conducted in infected and diseased needles gradually fall. 1981. Inocula of two isolates, one from Glypto On the blighted needles and green-shoot lesions, strobus pensilis (CC-139) and the other from Cryp many greenish brown to grayish brown powdery tomeria japonica (CC-85, Cercospora sequoiae), masses of conidia are produced. These symptoms were sprayed on potted seedlings of three conifers and signs seem to be quite similar to those of the (Table 2). Inoculated seedlings were kept under needle blight of (L.) RICH. moist conditions for 48 hours at 20•`30•Ž. Then, and T. mucronatum TEN caused by C. sequoiae (KO they were placed in greenhouse for two months.

* 小 林 享 夫=ス イ シ ョ ウ の 赤 枯 病 A summary of this paper was presented at the Autumn Meeting of Kanto Division, the Phytopathological Society of Japan, held on November 25, 1981, Utsunomiya. ** For . and Forest Prod, Res. Inst., Ibaraki 305林 業 試 験 場 162 J. Jpn. For. Soc. 68(4)'86

Table 1. Dimensions of Cercospora on Glyptostrobus and C. sequoiae

* Inoculated seedlings; a) The author, b) ITO et al. (1952), c) KOBAYASHI(1980), d) ITO et al. (1958), e) ZINNO(1969)

Table 2. Pathoeenieity of Cercospora-isolates from Glyptostrobus and Cryptomeria japonica

a) Isolate from Glyptostrobus pensilis , b) isolate from Cryptomeria japonica (Cercospora sequoiae), c) different seed sources, d) denominator, number of inoculated seedlings; numerator, number of positive infection, e) severity of the disease development and production of fruiting bodies; + slight, ++ moderate, +++ heavy, none

Results of the inoculation tests are given in Table 2. Both isolates developed typical needle-blight symptoms on all of the inoculated seedlings about a month after inoculation. Severe disease develop ment as observed in the field was recorded after two months of incubation. Dimensions of the fruiting bodies of the G. pensilis-isolate (CC-139) on the inoculated Cryptomeria japonica and C. fortunei HOOIBRENCKseedlings did not differ from those of Cercospora sequoiae recorded before (Table 1). V. Duration of Conidial Production and Overwintering The period of conidial production and germinabil ity of conidia on the diseased seedlings of G. pensi lis were examined from April 1981 to May 1982. Results are given in Table 3. As G. pensilis is a conifer, almost of all needles, including healthy and diseased ones, defoliate from late No vember to early December. The fungus on the fall en diseased needles may not serve as the primary infection source in the following spring as indicated by ITO and others (1954). On the other hand, needles borne directly on green shoots do not de foliate. All conidia on lesions of these surviving needles and green shoots disappear in December. The fungus overwinters within the lesions as young stroma covered with cuticula. In early April, overwintered young-stroma break through the cuti

Fig. 1. Cercospora sequoiae ELL. et EV. on cula and produce conidia gradually. In May, nu

Glyptostrobus pensilis merous conidial masses appear on these overwintered a, Stroma and conidiophores; b, young smooth lesions. These newly-produced conidia seem to be conidia and mature constricted conidia with warts the primary infection source at the beginning of the _??_ =10ƒÊm 日林 誌 68(4)'86 163

Fig. 2. Needle blight of Glyptostrobus pensilis caused by Cercospora sequoiae ELL. et EV. A, Seedling affected by needle blight; B, lesions on green shoot; C,stroma; D, conidia; E, stroma; F, conidia on Cryptomeria fortunei inoculated with Glyptostrobus-isolate; G, conidia on Cryptomeria japonica inoculated with Glyptostrobus-isolate

growing season. Conidia produced from April to spora sp. on G. pensilis seems to be identical with October on the lesions maintain great germinabili that of C. sequoiae observed on Cryptomeria japon ty. Duration of conidial production in the Cerco ica (ITO et al., 1954). 164 J. Jpn. For. Soc. 68(4)'86

Table 3. Production and germination of conidia Acknowledgement of Cercospora on Glyptostrobus pensilis

The author thanks Mr. Zenzo IWATA, Asakawa

Experimental Forest of the Forestry and Forest

Products Research Institute, for his kind help in

collecting the diseased materials periodically .

Literature cited

Anonymous: A list of diseases, insect pests, and

weeds in Korea. 424 pp, Korean Society of Plant

Protection, 1972

Anonymous: Forest pathology. 216pp, Peking, 1979 (in

Chinese)

HOMES, S. J.: Comparison of four similar fungi from Junip.

erus and related conifers. Mycologia 54: 62•`69, 1962

- and MAY, L. C.: Cercospora sequoiae no Brasil , Fitopatologia 7(1/2): 32•`34, 1972 a) At 20•Ž for 48hr, b)-none, +sparse, ++many, ITO, K., SHIBUKAWA, K., and KOPAYASHI, T.: Etiological +++ numerous and pathological studies on the needle blight of Cryp

tomeria japonica (I) Morphology and pathogenicity

VI. Discussion and Conclusion of the fungi inhabiting the blighted needles. Bull. Gov. The Cercospora sp. causing needle blight of G. For. Exp. Stn. 52: 79•`152, 1952*- ,-, and-: Blight of Sequoia pensilis was identified as C. sequoiae on the bases of the same morphological characteristics and pathoge gigantea seedlings caused by Cercospora cryptomeriae SHIRAI. J. Jpn. For. Soc. 40: 407•`410, 1958**-,-,

nicity to G. pensilis, C. japonica, and C. fortunei as and-: Etiological and patholog. shown in Tables 1 and 2. The hosts of C. sequoiae, ical studies on the needle blight of Cryptomeria

14 species belonging to 9 genera of Taxodiaceae and japonica(III) A comparison between Cercospora crypto- , have been recorded in Asia (Japan, meriae SHIRAI and Cercospora sequoiae ELLIS et EVER Korea, Taiwan, China, and the Philippines), North HART. Bull. Gov. For. Exp. Stn. 204: 73-90, 1967-,-, America (U. S. A.), and South America (Brazil) and TERASHITA, T.: ibid. (II) Physi ological and ecological characters of Cercospora cryp (Anonymous, 1972, 1979; HODGES,1962; HODGESand MAY, 1972; ITO et al., 1952; KOBAYASHI,1980, 1982 tomeriae SHIRAI, the most important pathogen of the a; MULDERand GIBSON,1973; SAWADA,1928). G. pen disease. Bull. Gov. For. Exp. Stn. 76: 27•`60, 1954* KOBAYASHI, T.: Needle blight of in silis is added as a new host for the fungus in this the Philippines. Annals. Phytopathol. Soc. Jpn. 46: 258 paper. The first infection source of the needle blight •` 262, 1980-: onto G. pensilis seedlings seems to be the conidia of Origin of the needle blight fungus of Crypto

C. sequoiae produced on the diseased seedlings of C. meria a japonica; history and topics. Sanrin 1175: 54•` japonica. Cryptomeria fortunei, another Chinese 59, 1982a**- conifer, also was proved to be quite susceptible to : Needle blight of Glyptostrobus pensilis and C. sequoiae, although its natural infection has not susceptibility of Japanese and Chinese species of been found in Japan. These Chinese conifers are Cryptomeria to the needle blight. Annals. Phytopathol. native in highland areas of southwestern and Soc. Jpn. 48: 135•`136, 1982b** southeastern China, and there is no record of C. se MULDER, J. L. and GISSON, I. A. S.: Cercospora sequoiae. CMI, Description of pathogenic fungi and bacteria, Set quoiae having been found on them in these areas. 37, No. 366, 2pp, 1973

Recently, the needle blight caused by C. sequoiae SAWADA, K.: Descriptive catalogue of the Formosan fungi was recorded on Cryptomeria fortunei in a lowland (IV). Rept. Dept. Agric. Gov. Res. Inst. 35, 123pp, area of central China (Anonymous, 1979). It had 1928** been supposed previously that C. sequoiae was in ZINNO, Y.: A needle blight of Taxodium distichum Rica. troduced from United States to Japan based on cer caused by Cercospora sequoiae ELLIS et EVERHART. J. tain circumstantial evidence (ITO et al., 1967; KO Jpn. For. Soc. 51: 183•`187, 1969 BAYASHI,1980, 1982a). Judged from high suscepti * Japanese with English summary bility of the two Chinese conifers tested in this ** Only in Japanese study, it is assumed also that C. sequoiae is not na (Received June 27, 1985) tive to China but was introduced from a foreign country.