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Three Drechslera species on Chloris
Notes and brief articles REFERENCES DENNIS, R. W. G. & WAKEFIELD, E. M. (1946). New or interesting British Fungi. Transactions of the British Mycological Society 29, 141-166.
GAMVNDi, I. J. & DENNIS, R. W. G. (1969). The status of Ascotremella Seaver (Fungi-Helotiales). Daruiiniana, Buenos Aires 15, 14-21. SEAVER, F. J. (1930). Photographs and Descriptions of Cup Fungi. X. Ascotremella. Mycologia :%2, 51-54.
THREE DRECHSLERA SPECIES ON CHLORIS
J. L. ALCORN Department of Primary Industries, Indooroopilly, Queensland Chloris gayana (Rhodes grass) is naturalized and
widely cultivated in Queensland. Of South African origin, it is grown on a wide range of soil types in the 700-1000 mm rainfall zone and is valued as an agronomic species because of its tolerance of drought, heavy grazing and burning (Tothill & Hacker, 1973). In south-eastern Queensland, C. gayana has been found as host to three leaf-infecting Drechslera species. D. australiensis M. B. Ellis and D. hawaiiensis M. B. Ellis. Both cause small, inconspicuous leaf lesions, punctiform to mostly narrc w linear or elliptical, up to 15 mm long but usually about 5 mm, and 1 mm or less wide, reddish brown, the older lesions sometimes pale centred, within the leaf blade or often also marginal, with an associated chlorosis when young leaves are infected. Both species have been recovered from a single collection, but D. hasoaiiensis is much more common than D. australiensis on this host. The latter species has also been collected on C. uirgata. Both are pathogenic to C. gayana inoculated under glasshouse conditions, producing symptoms similar to those seen in field collections. The third species causes a blighting syndrome, and appears sufficiently distinct in morphology, pathogenicity, and cultural characters from similar species to warrant the erection of a new taxon.
Drechslera chloridis Alcorn sp.nov. (Figs. 1-6) Coloniae amphigenae, effusae, griseae. Conidiophore
solitaria vel fasciculata, simplicia vel interdum ramosa, recta, flexuosa vel geniculata, septata, pallide brunnea
vel rufo-brunnea, apicem versus pallidiora, usque ad 1150 Jlm longa, 4-10 Jlm crassa, cellula basali 7'5-15 Jlm crassa, nodis fertilibus tumidis et verruculosis. Conidia curvata, subcylindrica vel fusiformia, pallide brunnea vel rufo-brunnea, in extremis rotundata, 2--9 (5)-distoseptata, 35-100 Jlm longa, 10-20 Jlm crassa, hilo nonprotrudenti, 3-4'5 Jlm diam. In foliis vivis Chloridis gayanae, Booie prope Kingaroy, Queensland, 12 Dec. 1972, J. L. Alcorn, BRIP 10965, holotypus; IMI 181067, isotypus. Lesions occur commonly at the tips or margins of the leaf blades, initially greyish-green, drying out to a bleached straw colour or more often grey, usually with a narrow reddish-brown margin and sometimes a narrow chlorotic band outside that, 50-185 mm long, 1'5-5 mm wide (Fig. 6). Less commonly the lesions are placed centrally in the lamina and do not extend to at least one margin. Sporulation is amphigenous, and sometimes more abundant on the lower surface. Conidiophores solitary, or in small fascicles, simple or occasionally branched, pale brown to reddish-brown, often paler towards the apex, straight, flexuous or geniculate, with the conidiogenous nodes usually well separated, and often swollen and verruculose, multiseptate, on the host 80-380 (183) Jim long, in culture on water agar + wheat straw 200-1150 (600) psn, tapering slightly from 5-10 Jlm diam near the base to 4-8'5 Jlm at the apex, which often is slightly inflated; basal cell swollen, 7'5-15 Jlm diam. Conidia pale golden brown to reddish brown, mostly curved, subcylindric to fusiform, ends rounded or base sometimes truncate, hilum inserted within the contour of the basal cell and
Drechslera chloridis
Fig. 1. Conidiophores from the host (x 400). Fig. 2. Conidiophore from water agar + wheat straw, near-v.v., 3 weeks (x 100). Fig. 3. Verruculose conidiogenous nodes (x 1000). Fig. 4. Conidia from water agar + wheat straw, near-u.v., 3 weeks (x 400). Fig. 5. PDA cultures of D. chloridis (left) and D. sorghicola, both 8 days at 26°. Fig. 6. Leaf symptoms on Chloris gayana ( x 2). Trans. Br. mycol. Soc. 67 (1), (1976).
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Notes and brief articles
2
3
4
5 Trans. Br. mycol. Soc. 67 (1), (1976).
Printed in Great Britain
149
Notes and brief articles rather inconspicuous, 3-4'5 (mostly 3'5-4) pm diam, all cells concolorous, 2-') (commonly 4-6) distoseptate, the septa thin and not accentuated, 35-100 x 10-20 pm. Secondary sporulation rare. This fungus resembles D . sorghicola (Lefebvre & Sherwin) Richardson & Fraser, especially in conidial morphology, and the collections were at first assigned to this species. However when grown under the same conditions (water agar + wheat straw, near-u, v. irradiation) D. sorghicola consistently has shorter conidiophores (80-320, mean 182 pm), and conidia which often exhibit secondary sporulation and have a greater number of septa (mean 6 compared with 5) than those of D. chloridis. Cultures on potato dextrose agar are quite different. D. sorghicola is very slow growing (2'5 mm per day at 26 °C), never covering a 9 em Petri plate. The colony margins are irregular, and growth rates vary in localized areas, producing fanshaped sectors. D. chloridis isolates grow rapidly and evenly (6'5 mm per day at 26°), quickly reaching the edge of a Petri plate. When freshly isolated they characteristically have small white aggregations of aerial hyphae, often in a more or less concentric pattern, which contrast sharply with the overall dark grey colour of the colony. Sporulation often is sparse in such cultures, in contrast to D. sorghicola which sporulates freely when first isolated. In infection tests, cultures of D. sorghicola are strongly pathogenic to sorghum, causing numerous large reddish-purple, more or less rectangular lesions (Alcorn & Mayers, 1975). They are nonpathogenic to C. gayana, or sometimes produce a few very small purplish elliptical lesions. D. chloridis, under the same conditions, causes a distinctive leaf blight in C. gayana, and only small numbers of punctiform purplish spots on sorghum. D . australiensis has been recorded on Chloris by Ellis (1971), and recently D. hawaiiensis was reported causing leaf and culm striping on C . gayana in the U.S.A. (Sonoda, 1974). A specimen of a fungus causing damage to Rhodes grass in Kenya (Robinson, 1960) has been examined and found to be conspecific with Queensland collections of D. chloridis. Specimens examined. D. australiensis : Chloris virgata, Gallon, 7 Nov. 1966, A. F. Gibbs, BRIU 2343a; C. uirgata, Ki\kivan, 4 June 1966, A. F. Gibbs, BRIU 2344; C. gayana, Booie near Kingaroy, 12 Dec. 1972,
Trans. Br . mycol. Soc. 67 (1), (1976).
J. L. Alcorn, BRIP 10967, IMI 181068; C. gayana , Kenmore , 6 Jan. 1974, J. L. Alcorn 74.002a, BRIP 10970. D. chloridis (all on C. gayatUl) : K itale area, Kenya, Aug. 1956, slides as BRIP 10962, dupl. as IMI 67876; Gatton, 8 Dec. 1972, J. L. Alcorn 72.150, BRIP 10963, dupl. as IMI 181064; Booie, 12 Dec. 1972, J. L. Alcorn 20334, BRIP 10964; Booie, 12 Dec. 1972, J. L. Alcorn 20338, BRIP 1°965, holorype (1MI 181067, isorype); Booie, 12 Dec. 1972, J. L. Alcorn 20339a, BRIP 1(1)66; Brookfield, 28 Mar. 1973, J. L. Alcorn 73.083a, BRIP 1°968; Lawes, 21 Feb. 1974, J. L. Alcorn 74.018, DRIP 10973; Taabinga near Kingaroy, 27 Feb. 1974, J. L. Alcorn 74.025, BRIP 10975; Mt . Tamborine, 6 May 1974, J. L. Alcorn 74.075, BRIP 10976: Kalbar, 8 June 1974, J. L. Alcorn 74.079, BRIP 10979; Laravale, 5 Mar. 1975, J. L. Alcorn 75.018, DRIP 10981; Kalbar, 21 June 1975, J. L. Alcorn 75.042, BRIP 10983. D. hawaiiensis (all on C. gayana): Beaudesert, 10 May 1966, A. F. Gibbs, BRIU 2339; Cunningham's Gap, 21 Apr. 1966, A. F. Gibbs, BRIU 2340; Springbrook, 19 Jan. 1967, A. F. Gibbs, BRIU 2341; Cooran, 4 June 1966, A. F. Gibbs, BRIU 2342; Brookfield, 28 Mar. 1973, J. L. Alcorn 73·083b, BRIP 10969; Kenmore, 6 Jan. 1974, J. L. Alcorn 74.002b, BRIP 10971 ; Beaudesert, 9 Jan. 1974, J. L. Alcorn 74.009, BRIP 10972; Taab inga, 27 Feb. 1974, J. L. Alcorn 74.024, BRIP 10974; Mt. Tamborine, 6 May 1974, J. L. Alcorn 74.076, BRIP 10977; Kalbar , 8 June 1974, J. L. Alcorn 74.078, BRIP 10978; [imboornba, 5 Mar. 1975, J. L. Alcorn 75.017, BRIP 10980; Laravale, 5 Mar. 1975, J. L. Alcorn 75·C19, DRIP 1°982. The helpful advice of Dr M . B. Ellis is recorded with appreciation. Dr J. J. Ondieki kindly lent a specimen of D . chloridis from Kenya. REFERENCES ALCORN, J. L. & MAYERS, P. E. (1975). Drechslera sorghicola on sorghum in Queensland . Australian Plant Pathology Society Newsletter 4, 26, 31. ELLIS, M . B. (1971). Dematiaceous hyphomycetes. Commonwealth Mycological Institute, Kew. ROBINSON, R. A. (1960). Annual Report, Department of Agriculture, Kenya, 1958. Vo1.lI, 18-24. Abstract in Review of Applied Mycology 39, 656, 1960. SONODA, R. M. (1974). Helminthosporium hawaiiense on Rhodesgrass in Florida . Plant Disease Reporter 58,49°. TOTHILL, J. C. & HACKER, J. B. (1973). The grasses of southeast Queensland. University of Queensland Press, St. Lucia.
Printed in Great Britain
GAMVNDi, I. J. & DENNIS, R. W. G. (1969). The status of Ascotremella Seaver (Fungi-Helotiales). Daruiiniana, Buenos Aires 15, 14-21. SEAVER, F. J. (1930). Photographs and Descriptions of Cup Fungi. X. Ascotremella. Mycologia :%2, 51-54.
THREE DRECHSLERA SPECIES ON CHLORIS
J. L. ALCORN Department of Primary Industries, Indooroopilly, Queensland Chloris gayana (Rhodes grass) is naturalized and
widely cultivated in Queensland. Of South African origin, it is grown on a wide range of soil types in the 700-1000 mm rainfall zone and is valued as an agronomic species because of its tolerance of drought, heavy grazing and burning (Tothill & Hacker, 1973). In south-eastern Queensland, C. gayana has been found as host to three leaf-infecting Drechslera species. D. australiensis M. B. Ellis and D. hawaiiensis M. B. Ellis. Both cause small, inconspicuous leaf lesions, punctiform to mostly narrc w linear or elliptical, up to 15 mm long but usually about 5 mm, and 1 mm or less wide, reddish brown, the older lesions sometimes pale centred, within the leaf blade or often also marginal, with an associated chlorosis when young leaves are infected. Both species have been recovered from a single collection, but D. hasoaiiensis is much more common than D. australiensis on this host. The latter species has also been collected on C. uirgata. Both are pathogenic to C. gayana inoculated under glasshouse conditions, producing symptoms similar to those seen in field collections. The third species causes a blighting syndrome, and appears sufficiently distinct in morphology, pathogenicity, and cultural characters from similar species to warrant the erection of a new taxon.
Drechslera chloridis Alcorn sp.nov. (Figs. 1-6) Coloniae amphigenae, effusae, griseae. Conidiophore
solitaria vel fasciculata, simplicia vel interdum ramosa, recta, flexuosa vel geniculata, septata, pallide brunnea
vel rufo-brunnea, apicem versus pallidiora, usque ad 1150 Jlm longa, 4-10 Jlm crassa, cellula basali 7'5-15 Jlm crassa, nodis fertilibus tumidis et verruculosis. Conidia curvata, subcylindrica vel fusiformia, pallide brunnea vel rufo-brunnea, in extremis rotundata, 2--9 (5)-distoseptata, 35-100 Jlm longa, 10-20 Jlm crassa, hilo nonprotrudenti, 3-4'5 Jlm diam. In foliis vivis Chloridis gayanae, Booie prope Kingaroy, Queensland, 12 Dec. 1972, J. L. Alcorn, BRIP 10965, holotypus; IMI 181067, isotypus. Lesions occur commonly at the tips or margins of the leaf blades, initially greyish-green, drying out to a bleached straw colour or more often grey, usually with a narrow reddish-brown margin and sometimes a narrow chlorotic band outside that, 50-185 mm long, 1'5-5 mm wide (Fig. 6). Less commonly the lesions are placed centrally in the lamina and do not extend to at least one margin. Sporulation is amphigenous, and sometimes more abundant on the lower surface. Conidiophores solitary, or in small fascicles, simple or occasionally branched, pale brown to reddish-brown, often paler towards the apex, straight, flexuous or geniculate, with the conidiogenous nodes usually well separated, and often swollen and verruculose, multiseptate, on the host 80-380 (183) Jim long, in culture on water agar + wheat straw 200-1150 (600) psn, tapering slightly from 5-10 Jlm diam near the base to 4-8'5 Jlm at the apex, which often is slightly inflated; basal cell swollen, 7'5-15 Jlm diam. Conidia pale golden brown to reddish brown, mostly curved, subcylindric to fusiform, ends rounded or base sometimes truncate, hilum inserted within the contour of the basal cell and
Drechslera chloridis
Fig. 1. Conidiophores from the host (x 400). Fig. 2. Conidiophore from water agar + wheat straw, near-v.v., 3 weeks (x 100). Fig. 3. Verruculose conidiogenous nodes (x 1000). Fig. 4. Conidia from water agar + wheat straw, near-u.v., 3 weeks (x 400). Fig. 5. PDA cultures of D. chloridis (left) and D. sorghicola, both 8 days at 26°. Fig. 6. Leaf symptoms on Chloris gayana ( x 2). Trans. Br. mycol. Soc. 67 (1), (1976).
Printed in Great Britain
Notes and brief articles
2
3
4
5 Trans. Br. mycol. Soc. 67 (1), (1976).
Printed in Great Britain
149
Notes and brief articles rather inconspicuous, 3-4'5 (mostly 3'5-4) pm diam, all cells concolorous, 2-') (commonly 4-6) distoseptate, the septa thin and not accentuated, 35-100 x 10-20 pm. Secondary sporulation rare. This fungus resembles D . sorghicola (Lefebvre & Sherwin) Richardson & Fraser, especially in conidial morphology, and the collections were at first assigned to this species. However when grown under the same conditions (water agar + wheat straw, near-u, v. irradiation) D. sorghicola consistently has shorter conidiophores (80-320, mean 182 pm), and conidia which often exhibit secondary sporulation and have a greater number of septa (mean 6 compared with 5) than those of D. chloridis. Cultures on potato dextrose agar are quite different. D. sorghicola is very slow growing (2'5 mm per day at 26 °C), never covering a 9 em Petri plate. The colony margins are irregular, and growth rates vary in localized areas, producing fanshaped sectors. D. chloridis isolates grow rapidly and evenly (6'5 mm per day at 26°), quickly reaching the edge of a Petri plate. When freshly isolated they characteristically have small white aggregations of aerial hyphae, often in a more or less concentric pattern, which contrast sharply with the overall dark grey colour of the colony. Sporulation often is sparse in such cultures, in contrast to D. sorghicola which sporulates freely when first isolated. In infection tests, cultures of D. sorghicola are strongly pathogenic to sorghum, causing numerous large reddish-purple, more or less rectangular lesions (Alcorn & Mayers, 1975). They are nonpathogenic to C. gayana, or sometimes produce a few very small purplish elliptical lesions. D. chloridis, under the same conditions, causes a distinctive leaf blight in C. gayana, and only small numbers of punctiform purplish spots on sorghum. D . australiensis has been recorded on Chloris by Ellis (1971), and recently D. hawaiiensis was reported causing leaf and culm striping on C . gayana in the U.S.A. (Sonoda, 1974). A specimen of a fungus causing damage to Rhodes grass in Kenya (Robinson, 1960) has been examined and found to be conspecific with Queensland collections of D. chloridis. Specimens examined. D. australiensis : Chloris virgata, Gallon, 7 Nov. 1966, A. F. Gibbs, BRIU 2343a; C. uirgata, Ki\kivan, 4 June 1966, A. F. Gibbs, BRIU 2344; C. gayana, Booie near Kingaroy, 12 Dec. 1972,
Trans. Br . mycol. Soc. 67 (1), (1976).
J. L. Alcorn, BRIP 10967, IMI 181068; C. gayana , Kenmore , 6 Jan. 1974, J. L. Alcorn 74.002a, BRIP 10970. D. chloridis (all on C. gayatUl) : K itale area, Kenya, Aug. 1956, slides as BRIP 10962, dupl. as IMI 67876; Gatton, 8 Dec. 1972, J. L. Alcorn 72.150, BRIP 10963, dupl. as IMI 181064; Booie, 12 Dec. 1972, J. L. Alcorn 20334, BRIP 10964; Booie, 12 Dec. 1972, J. L. Alcorn 20338, BRIP 1°965, holorype (1MI 181067, isorype); Booie, 12 Dec. 1972, J. L. Alcorn 20339a, BRIP 1(1)66; Brookfield, 28 Mar. 1973, J. L. Alcorn 73.083a, BRIP 1°968; Lawes, 21 Feb. 1974, J. L. Alcorn 74.018, DRIP 10973; Taabinga near Kingaroy, 27 Feb. 1974, J. L. Alcorn 74.025, BRIP 10975; Mt . Tamborine, 6 May 1974, J. L. Alcorn 74.075, BRIP 10976: Kalbar, 8 June 1974, J. L. Alcorn 74.079, BRIP 10979; Laravale, 5 Mar. 1975, J. L. Alcorn 75.018, DRIP 10981; Kalbar, 21 June 1975, J. L. Alcorn 75.042, BRIP 10983. D. hawaiiensis (all on C. gayana): Beaudesert, 10 May 1966, A. F. Gibbs, BRIU 2339; Cunningham's Gap, 21 Apr. 1966, A. F. Gibbs, BRIU 2340; Springbrook, 19 Jan. 1967, A. F. Gibbs, BRIU 2341; Cooran, 4 June 1966, A. F. Gibbs, BRIU 2342; Brookfield, 28 Mar. 1973, J. L. Alcorn 73·083b, BRIP 10969; Kenmore, 6 Jan. 1974, J. L. Alcorn 74.002b, BRIP 10971 ; Beaudesert, 9 Jan. 1974, J. L. Alcorn 74.009, BRIP 10972; Taab inga, 27 Feb. 1974, J. L. Alcorn 74.024, BRIP 10974; Mt. Tamborine, 6 May 1974, J. L. Alcorn 74.076, BRIP 10977; Kalbar , 8 June 1974, J. L. Alcorn 74.078, BRIP 10978; [imboornba, 5 Mar. 1975, J. L. Alcorn 75.017, BRIP 10980; Laravale, 5 Mar. 1975, J. L. Alcorn 75·C19, DRIP 1°982. The helpful advice of Dr M . B. Ellis is recorded with appreciation. Dr J. J. Ondieki kindly lent a specimen of D . chloridis from Kenya. REFERENCES ALCORN, J. L. & MAYERS, P. E. (1975). Drechslera sorghicola on sorghum in Queensland . Australian Plant Pathology Society Newsletter 4, 26, 31. ELLIS, M . B. (1971). Dematiaceous hyphomycetes. Commonwealth Mycological Institute, Kew. ROBINSON, R. A. (1960). Annual Report, Department of Agriculture, Kenya, 1958. Vo1.lI, 18-24. Abstract in Review of Applied Mycology 39, 656, 1960. SONODA, R. M. (1974). Helminthosporium hawaiiense on Rhodesgrass in Florida . Plant Disease Reporter 58,49°. TOTHILL, J. C. & HACKER, J. B. (1973). The grasses of southeast Queensland. University of Queensland Press, St. Lucia.
Printed in Great Britain