Publication No. 30 Florida Agricultural Experiment Station Journal

Publication No. 30
Florida Agricultural Experiment
Station Journal Series No. 5519
The Fungal Flora of Waterhyacinth in Florida
By
K.E. Conway, T.E. Freeman and R. Charudattan
Plant Pathology Department, University of Florida
Publicatiol1 No. 30
Florida A~ricllltural FX{Jerimcl/(
,,)'(atiol1 Journal Series No. 5519
The
FIII/~al
Flora of Jl'atcrhyacil1(11 ;11 Florida
lJy
K.E. Co 11 way. T.E. rrl't'l11al1 ami R. C!wrudalla"
Plant PallwloKY f)/'par(/I/('f/I. UlliJ'ersily of Florida
ABSTRACT
THE FUNGAL FlOl1.A OF \-:.ATER.-'-fYACINTH IN FLORIDA, PART I.
?C.E. Gonway, T.E.Freem:l.ll and. R. CharudattAn.
Plant Pathology Department
University of Florida, Gainesville, 32611
Research ,las initiated to survey, isolate, identify, test,
and catalogue all fungi associated ,·dth waterhyacinths.
The
ultirna:te goal of this project is to find organisms that can be
used as biological controls to limit the growth rate or destroy
the Haterhyacinth.
An understanding of the role played by fungi
in the decline and death of waterhyacinthhas been aided by
studying both saprophytes andparsites.
30 species of fungi.
This report includes
The location, date of colJ.ection, patho-
genicity, and references for each isolate is provided.
A more
effective biocontrol should be possible by knowing vlhat environmental factors favor the presence of fungal pathogens on the.
waterhyacinth.
..
THE FUNGAL FLORA OF WATERHYACINTH IN FLORIDA
By
K.E. Conway
T.E. Freeman
and
R. Charudattan
PUBLICATION NO. 30
FLORIDA WATER RESOURCES RESEARCH CENTER
and
FLORIDA AGRICULTURAL EXPERIMENT STATION
JOURNAL SERIES NO. 5519
,
September, 1974
The work upon which this report is based was supported in part
by funds provided by the United States Department of the
Interior, Office of Water Resources Research as
Authorized under the Water Resources
Research Act of 1964.
Part I
K.E. Conway, T.E. Freeman, R. Charudattan
Plant Pathology Dept., Univ. of Florida, Gainesville, 32611.
Aquatic weeds in many lakes and streams in Florida
have become the concern of scientists and sportsmen.
Although aquatic pl;lnts perform a function, an overabundance can rapidly lead to a decrease in boating, fishing
and environmental quality. Therefore, there is a need to
limit the growth and spread of certain aquatic weeds.
Currently, the number one problem is the waterhyacinth,
estimated to infest 200-300 thousand acres of water in the
state of Florida.
In November of 1973, a project was initiated to
survey, isolate, identify, test, and catalogue all fungi
associated with waterhyacinths. The objective of this
research was to find fungal organisms that could be used as
biological controls to limit the growth rate or destroy the
waterhyacinth. It was felt that a broad ranged approach
looki ng at both parasites and saprophytes would significantly augment our understanding of the role played by
fungi in the decline and death of the waterhyacinth. This
approach would also aid our understanding of the natural
succession of fungal organisms on the waterhyacinth. More
effective biocontrol should be possible by knowing what
environmental factors favor the presence of fungal
pathogens.
It is important that a catalogue of organisms be
presented to form the foundations for further research.
This report includes 30 species of fungi that have been
found on waterhyacinth since the inception of this project.
Each species is briefly described and information
concerning its effect on waterhyacinth is presented. The
organisms listed in this report represent two subdivisions of
the Eumycota, the Ascomycotina and the Deuteromycotina.
I.
ASCOM YCOTI NA-A. Class Pyrenomycetes
1.
MELANOSPORA ZAIAE Corda (Fig. 1)
The fungus was isolated from the leaves of
waterhyacinth. The perithecia (230J.L diam.) are superficial
with a slender neck 200-300 J.L long. The asci (44-70 x 2211)
are long stal ked and evanescent. The ascospores (20-22 x
13-14 J.L) are unicellular, smooth, and dark brown in color.
Pathogenicity-Not confirmed
Location-Lake Alice, University of Florida campus.
Date-March
Ref.-Dennis, 1968; Doguet, 1955.
B.
Class Loculoascomycetes
2.
LEPTOSPHAERULINA sp. (Fig. 2)
This organism was isolated from necrotic spots at the
tips of the leaves. Ascostroma (150 J.L diam.) are erumpent
and the asci measure 65-77 x 40-45 J.L. The asci are
bitun icate, possessing two distinct wall layers. Ascospores
(33 x 11 11) are hyaline, and muriform.
Pathogenicity-Not confirmed
Location-Lake Alice, University of Florida campus.
Date-December
Ref.-Von Arx, 1970.
3.
DIDYMELLA EXIGUA (Niessl.) Sacco (Fig. 3)
This fungus was isolated from dying leaves of
waterhyacinth. Ascostroma (100-150 11) are singly im. mersed in the leaf beneath the stoma. Asci measure 35-45 x
6-8 11 and the ascospores (12-15 x 5-6 J.L ) are two-celled and
hyaline. Imperfect state-Ascochyta
Pathogenicity-Not confirmed-both Didyme//a exigua and
Ascochyta imp. state
Location-Rodman Reservoir; Lake Alice, University of
Florida campus
Date-December-January
Ref. -Corbaz, 1957.
4.
MYCOSPHAERELLA TASS/ANA (de Not.)
Johanson (Fig. 4)
This organism was isolated from declining waterhyacinth leaves. This genus is morphologically similar to
Didyme//a. Mycosphaere//a differs by: possessing a smaller
ascocarp, having spores with a greater length-width ratio
(with the bottom cell longer than the apical cell), lacking
paraphyses, and lacking an Ascochyta imperfect stage in
culture. The ascocarp measures 60-90 J.L, the asci, 35-40 x
9-10 J.L, and the ascospores, 16-20 x 5-6/1.
Pathogenicity-slight
Location-Lake Alice, Rodman Reservoir.
Date-April
Ref.-Von Arx, 1949.
II.
DEUTEUROMYCOTINA-A. Coe/omycetes
5.
PHOMA spp. (Fig. 5)
Several species of p,homa have been isolated from
waterhyacinth a'nd possess varying pathogenicity to
waterhyacinth. Until further elaboration is possible a broad
interpretation of the genus will be used to include species
of Phy//osticta and Peyronellaea as well as small spored
species similar to Asteromella. Pycnidia measure 100 11
diam., and are immersed to superficial. Conidia measure 5-6
x 2-3 J.L.
Pathogenicity-varies with species, from moderate to none.
Location-Rodman Reservoir, Lake Alice, Labelle, Fla.
Date-present throughout survey
Ref.-Von Arx, 1970.
6.
BOTRYODIPLOIDEA sp. (Fig. 6)
The genus Botryodip/oidea is often confused with the
genus of Macrophoma. The conidia are at first hyaline,
one-celled and thick walled, like Macrophoma. As they
mature in the pycnidium they become brown, two-celled
and the conidium wall may be slightly striated in color. The
conidia measure 27-32 x 13-15 11. Botryodip/oidea was
found erumpent on floral tubes of waterhyacinth.
Pathogenicity-slight .
Locati on- Rod man Reservoi r
Date-March
Ref.-Von Arx, 1 9 7 0 . ,
B.
Hyphomycetes
7.
CEPHALOTR/CHUM sp. (Fig. 7)
3
This fungus has been found on dead waterhyacinth
leaves. The conidiophores are united into a synnema. The
synnemata are light brown, capitate, with the stipe
composed of parallel hyphae. The tips of the conidiophores
are annellidic, conidia are one-celled, catenulate and are
held together in a dry head. Conidia measure 8-10 x 4-5 }.1..
Synnemata are 110-120 jJ. in length. Cephalotrichum link is
the genus selected by Hughes (1958) to replace the genus
Doratomyces Corda.
Pathogenicity-Not confirmed
Location-Lake Alice
Date-February
Ref.-Morris, 1963; Morton and Smith, 1963.
8.
MYCOLEPTODISCU5 TERRE5TRI5
(Gerdemann) Ostrazeski (Fig. 8)
This unique organism was isolated by Dr. R.
Charudattan from waterhyacinths at Manatee Springs,
Florida. Conidia are formed on a dark sporodochium and
their development is enhanced by placing cultures in
near-UV light. The sporodochium is flat and one-celled
thick 200-300 }1 diam. The individual conidiogenous cells
are phialidic. The conidia are allantoid, two-celled, hyaline,
20-35 x 5-7 /1, with seta at each end 8-18 fl long. Conidia
are held in a mucilagenous mass.
Pathogenicity-slight to none, producing a small zonate leaf
spot.
Location-Manatee Springs, Fla,
Date- january-February
Ref.-Sutton, 1973,
9,
MYROTHECIUM ClNTUM (Corda) Sacco
(Fig. 9)
This fungus was isolated from waterhyacinth leaves.
The fungus produces sporodochium and the conidia are
held in a mucilagenous mass, The conidia are dark brown
and may appear green in mass. Conidia measure 11-15 x
3-4.611 and are spirally striated,
Pathogenicity-f']ot confirmed
Location-Lake Alice
Date-March
Ref-M.B. Ellis, 1971.
10. EPICOCCUM PURPURASCEN5 Ehrenb,
ex Schlecht (Fig, 10)
Epicoccum purpurascens is found abundantly on
declining and dead waterhyacinths. It is a common
saprophyte. Epicoccum produces sporodochium, The
conidia are large, 18-22 fl diam" dark brown and muriform.
Pathogenicity-Not confirmed
location-Ubiquitous
Date-throughout survey
Ref-M.B, Ellis, 1971.
11, ALTERNARIA spp. (Fig, 11)
Most Alternaria species are saprophytic on waterhyacinth. Conidia are dark brown, muriform, measure 8-10
x 30-3511, and possess a beak as large as 20 fllong.
Pathogenicity-Not confirmed
Location-Ubiquitous
Date-throughout survey
Ref-Von Arx, 1970,
12,
ASPERGILLUS
A.
4
A. flavus Link (Fig. 12)
R
A. niger Van Tiegh (Fig. 13)
Species of Aspergillus are commonly isolated from
declining and dead waterhyacinths, The most common
species encountered is A. niger, The presence of A, ffavus in
waterhyacinth should add a note of caution to those
utilizing waterhyacinths as feed supplements, due to the
possibility of aflatoxin production during feed preparation,
Pathogenicity-none
Location-Lake Alice, Rodman Reservoir
Date-January-February
Ref.-Raper & Fennell, 1965
13.
ACREMONIUM ZONA TUM (Sawada)
Gams, (CEPHALOSPORIUM ZONA TUM)
(Fig, 14)
This organism has been found in Florida, Louisiana,
Panama, Puerto Rico, India and EI Salvador. It produces a
zonate leaf spot. The conidiophores of this isolate are
highly branched and phialidic. The conidia are 4-5 x 3 /1.
This fungus is currently being field tested by Dr. TE,
Freeman and appears to be useful as a means of reducing
the productivity of the waterhyacinth. Cultures have been
deposited (CBS 211,74) with the Centraalbureau Voor
Schimmelcultures, Baarn, Netherlands.
Pathogenicity-good to excellent. Produces a zonate leaf
spot.
location-Lake Alice, Newnam Lake, Fort Lauderdale
Date-October-December
Ref.-Gams, 1971; Rintz, 1973.
14. BIPOLARIS spp, (Fig, 15)
Several species of the Bipolaris group have been
isolated from waterhyacinth, Dr. R. Charudattan isolated
the first species that is highly virulent on waterhyacinth
His greenhouse tests show
from the Dominican
this isolate, designated /-felminthosporium stenospilum
(Bipolaris stenospila), to be an aggressive pathogen of
waterhyacinth. Other species of Bipo/aris, B. cynodontis
(Marig,) Shoemaker have recently been discovered from the
La Belle, Florida area and Lake Alice, Greenhouse tests are
currently being undertaken on these species,
Pathgoenicity-good (B. stenospila) Other species-slight
to none.
Location-La Belle, Fla., Lake Alice
Date-May
Ref.-M,B. Ellis, 1971; luttrell, 1951.
15. CERCOSPORA sp. (Fig. 16)
Two. species of Cercospora have been found and
isolated from waterhyacinth, Cercospora piaropi Tharp, has
been reported on waterhyacinths in Florida as causing an
oval leaf spot by Freeman and Charudattan. Conidia
measure 55-121 x 3.4-4.4 fl. Another species has also been
isolated with larger conidia 140-180 x 4-5 fl, and which also
produces oval to irregular spots on waterhyacinth leaves,
Pathogenicity-good
location-Rodman Reservoir, Lake Alice
Date-December-May
Ret-Freeman & Charudattan, 1974; Chupp, 1953,
16, CLADOSPORIUM spp. (Fig, 17)
Cladosporium is a ubiquitous genus and a common
saprophyte on waterhyacinth, it is easily diagnosed by its
long chains of conidia and the branched ramo-conidia.
Pathogenicity-Not confirmed
Location-ubiquitous
Date-throughout investigation
Ref.-M.B. Ellis, 1971.
17. CURVULARIA spp.
A.
C. affinis Boedijn (Fig. 18)
B.
C. penniseti (Mitra) Boedijn (Fig. 19)
Curvularia is a very common organism on waterhyacinth. Several species have been isolated and tested on
waterhyacinth. Curvularia affinis is a saprophyte. Where as,
C. penniseti produced a leaf spot in preliminary greenhouse
studies.
Pathogenicity-varies, usually none
Location-Lake Alice, Rodman Reservoir
Date-throughout study, abundant May
Ref.-M. B. Ellis, 1971.
18. DENDRYPHIELLA INFUSCANS (Thum)
M.B. Ellis (Fig. 20)
This organism occurred only a few times, usually on
dead leaf material, in association with Alternaria, Cladosporium and Epicoccum. The distinguishing features of
this genus are the tall conidiophore with terminal and
intercalary nodose swellings and the branched chains of
conidia. The conidia are brown, smooth, 0-2 septate and
measure 9-16 x 4-7 fJ..
Pathogenicity-not tested
Location-Lake Alice
Date-February
Ref.-M.B. Ellis, 1971.
19. EXSEROHILUM PROLA TUM Leonard & Suggs
(Fig. 21)
This species was isolated from a leaf spot on
waterhyacinth. Exserohilum is a new genus derived from
the Bipolaris group of the Helminthosporium complex.
Exserohilum germinates from both ends of the conidium
and the conidium possesses a protuberant hilum.
Exserohilum proia tum is morphologically simi.lar to
Exserohilum (Bipolaris) rostratum except E. prolatum lacks
the heavy septations near the tip and base of the conidium.
The conidium measures 88-110-135 x 15-18 fJ..
Pathogenicity-under investigation
Location-Lake Alice
Date-May
Ref.- Leonard & Suggs, 1974.
20. MEMNONIELLA SUBSIMPLEX (Cke.)
Deighton (Fig. 22)
This organism is not encountered too frequently,
however, when present it is usually in the saprophyte
complex consisting of Alternaria, Cladosporium, Epicoccum and others. The long (130 fJ.) hyaline conidiophore is
terminated by 6-8 phialides, 8-9 x 2-3 fJ.. Dark, sphaerical
conidia, 6-8 fJ. diam., are formed.
Pathogenicity-not tested
Location-Rodman Reservoir and Lake Alice
Date-December
Ref.-M.B. Ellis, 1971.
21. PERICONIA BYSSOIDES Pers. ex Merat
(Fig. 23)
Periconia byssoides is also associated with the
saprophyte complex occurring on waterhyacinth. The
conidiophores are up to 1000 fJ. long. The conidiophore is
terminated by a cross wall near the tip producing a short
apical cell. The conidiogenous cells are formed over the
apex of this cell. The sphaerical conidia are verrucose,
13-14 fJ. in diam.
Pathogenicity-slight
Location-Rodman Reservoir, Lake Alice
Date-January-February
Ref.-M.B. Ellis, 1971.
22. PITHOMYCES CHARTA RUM (Berk. & Curt.)
M.B. Ellis (Fig, 24)
The presence of this fungus is of critical importance
to those attempting to produce a cattle feed from
waterhyacinths. Pithomyces chartarum is a saprophyte
usually found on senescent grasses and under the correct
environmental conditions produces a toxin, sporidesmin,
that can cause facial eczema of sheep and cattle, loss of
weight, icterus and photosensitivity. The conidia contain
the toxin and unless the toxin is inactivate, it could in
certain periods of the year cause problems to cattle fed the
waterhyacinth food stuff.
Pathogenicity-Not confirmecl
Location-Rodman Reservoir, Lake Alice
Date-December-March
Ref.-M.B. Ellis, 1971.
23. NIGROSPORA
A.
Nigrospora oryzae (Berk. & Br.)
Petch (Fig. 25)
B.
Nigrospora sphaerica (Sacc.) Mason
(Fig. 26)
Nigrospora sphaerica has been reported as a weak
pathogen of waterhyacinth. Its performance is enhanced
when used in combination with the waterhyacinth weevil
(Neochetina). Nigrospora sphaerica has larger conidia
(16-18 fJ.) than N. oryzae (12-14 fJ.).
Pathogenicity-weak
Location-Rodman Reservoir, Lake Alice, Fort Lauderdale,
La Belle, Fla. area
Date-January-February-May
Ref.-M.B. Ellis, 1971.
24. THYSANOPHORA LONGISPORA Kendrick
(Fig. 27)
Thysanophora longispora is a saprophyte found only
on dead conifer needles in Canada. Its presence on
waterhyacinth in Florida must be termed unusual.
Conidiophores are over 1000 fJ. long,metulae measure 20 fJ.,
phialides 20-25 x 7 fJ., and conidia are catenulate, 9-14 x 3-4
fJ.. The mycelium appears to be encrusted with crystals.
Pathogenicity-Not determined
Location-Lake Alice
Date-January, March
Ref.-Barron, 1972.
25. SCOLECOBASIDIUM HUMICOLA Barron &
Busch (Fig. 28)
This organism is usually associated with the soil,
particularly those high in organic matter. The conidia are
two-celled, cylindrical, not constricted at the septum, finely
echinulate and measure 7-15 x 2-4 fJ.. The conidia are
produced on tubular extensions of the conidiophore.
Pathogenicity-not tested
5
location-lake Alice
Date- February
Ref.-M.B. Ellis, 1971; Barron, 1972.
26. STEMPHYLIUM VESICARIUM (Wallr.)
Simmons (Fig. 29)
Initial greenhouse observations of the pathogenicity
of this fungus indicate it may have a potential for control
of waterhyacinth. The conidia are large, 39-55 x 16-20 /1,
muriform, dark brown, and finely echinulate.
Pathogenicity-slight
location-La Belle, Fla. area
Date-May
Ref.-Simmons, 1969; M.B. Ellis, 1971.
27. SPOROBOLOMYCES sp. (Fig. 30)
This fungus has been observed several ti mes in cleared
leaf section of waterhyacinth. It has not been cultured and,
therefore, not much is known about the mode of conidial
formation. A similar fungus has been isolated by Dr.
Charudattan from the Dominican RepUblic. The conidia are
about 10-11 /1 in diam.
Pathogenicity-not tested
Location-Rodman Reservoir
Date-December
Ref.-Ellis, 1971.
6
Acknowledgements
The authors are grateful for the help of Drs. j. W.
Kimbrough and H.H. Luke in reviewing this paper. This
research was supported by U.S. Army Corps of Engineers
Contract No. DACW 73-73-C-0049, Florida Department of
Natural Resources and by the U.S. Department of Interior,
Office of Water Resources as authorized by the Water
Resources Act of 7964.
18.
19.
Von Arx, J .A. 1949. Beitra'ge zur kenntnis der
gattung Mycosphaerella. Sydowia. 3:28-100.
Von Arx, J.A. 1970. The Genera of Fungi Sporulating
in Pure Culture. J. Cramer. Lehre, Germany. 288 p.
References
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Barron, G. L. 1972. The Genera of Hyphomycetes from
soil. R.E. Krieger Publ. Co., New York, N.Y. 364 pp.
Chupp, C. 1953. A Monograph of the Fungus Genus
Cercospora. Ithaca, N.Y. 667 pp.
Corbaz, R. 1957. Recherches Sur Ie genre Didymella
Sacco Phytopath Z. 28:375-414.
Dennis, R.W.G. 1968. British Ascomycetes. J. Cramer,
Lehre, Germany. 455 pp.
Doguet, G. 1955. Le Genre "Melanospora"; Biologie,
morphologie, Developpement, Systematique. Le Botaniste
39:1-313.
Ellis, M.B. 1971. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England. 608 pp.
Freeman, T.E., & R. Charudattan. 1974. Occurrence of
Cercospora piaropi on Waterhyacinth in Florida.
Plant Dis. Reptr. 58:277-278.
Gams, W. 1971. Cephalosporiumartige Schimmelpilze
(Hyphomycetes). G. Fischer Verlag. Stuttgart, Germany.
262 pp.
Hughes, S.J. 1958. Revisiones Hyphomycetum aliquot cum
Appendice de nominibus rijiciendis. Canad. J. Bot.
36:727-836.
Leonard, K.J., & E.G. Suggs. 1974. Setosphaeria
prolata, The Ascigerous State of Exserohilum prolatum.
Mycologia 66: 281-297.
Luttrell, E.s. 1951. A Key to Species of Helminthosporium Reported on Grasses in the United States.
Plan Dis. Reptr. SuppL 201 :59-67.
Morris, E.F. 1963. The Synnematous Genera of the
Fungi Imperfecti. Western Illinois University, Macomb,
III. Series 3. 143 p.
Morton, F.J., & G. Smith. 1963. The Genera
Scopulariopsis Bainier, Microascus Zukal, and
Doratomyces Corda. CMI Mycological Papers, No. 68.
Raper, K.B., & D.1. Fennel. 1965. The Genus Aspergillus.
2nd ed. Williams and Wilkens Co., Baltimore. 686 p.
Rintz, R.E. 1973. A Zonal Leaf Spot of Waterhyacinth
caused by Cephalosporium zonatum. Hyacinth Control
J. 11 :41-44.
Simmons, E.G. 1969. Perfect States of Stemphylium
Mycologia 61 :1-26.
Sutton, B.C. 1973. Pucciniopsis, Mycoleptodiscus
and Amerodiscosiella. Trans. Br. Mycol. Soc.
60: 525-536.
7
Illustrations
Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Perithecia, asci (arrows) and ascospores of
Melanospora Zamiae. X 100.
Ascostroma, asci (bitunicate), and ascospores of
Leptosphaerulina sp. X 150.
Ascostroma of Didymella exigua. X 150.
Ascostroma of Mycosphaerella Tassiana in a
cross section of the leaf beneath a stoma. X 150.
Pycnidium of Phoma sp. with extruded conidia.
X 150.
Fig. 6.
The neck of a pycnidium of Botryodiploidea sp.
Note the presence of both one-celled, hyaline immature conidia and two-celled dark mature conidia.
Fig. 7.
Fig. 8.
Cephalotrichum sp. X 150.
Sporodochium and two-celled hyaline conidia of
Mycoleptodiscus terrestris. X 150.
Striated conidia of Myrothecium cintum. X
X 150.
Fig. 9.
1,500.
Fig. 10.
Fig.
Fig.
Fig.
Fig.
11.
12.
13.
14.
Fig. 15.
Fig. 16.
Fig. 17.
Sporodochium showing dark muriform conidia of
Epicoccum purpurascens. X 150.
Conidia of Alternaria sp. X 150.
Conidial head of Aspergillus flavus. X 150.
Conidial head of Aspergillus niger. X 150.
Branched phialides and conidia of Acremonium
zona tum (Cephalosporium). X 150.
Conidia of Bipolaris cynodontis. X 150.
A conidium of Cercospora sp. X 150.
Branched conidial chain of Cladosporium sp.
X 675.
Fig. 18.
Fig. 19.
Fig. 20.
Fig. 21.
Fig. 22.
Fig. 23.
Fig. 24.
Conidia attached to conidiophore of Curvularia
affinis. X 150.
Conidia of Curvularia penniseti. X 150.
Conidia and conidiophore of Dendryphiella
infuscans. X 150.
Conidium of Exserohilum prolatum. X 150.
Conidiophore of Memnoniella subsimplex
with phialidic conidiogenous cells and dark
oval conidia. X 150.
Conidiophore and conidia of Periconia
byssoides. X 675.
Muriform conidia of Pithomyces chartarum.
X 150.
Fig. 25.
Fig. 26.
Fig. 27.
Fig. 28.
Fig. 29.
Fig. 30.
8
Conidium of Nigrospora oryzae. Note the
pedicel below the conidium. X 1,500.
Conidium of Nigrospora sphaerica. X 1,500.
Conidiophore, phial ides and conidia of
Thysanophora longispora. X 150.
Conidia of Scolecobasidium humicola. X 1,500.
Conidium of Stemphylium vesicarium. X 675.
Conidia of Sporobolomyces sp. within the
epidermal cells of a waterhyacinth leaf. X 675.
fi' . .• .
\~U
9
10
11