Mycological Society of America
The Biology and Taxonomy of Rust Fungi Associated with the Neotropical Vine Mikania
micrantha, a Major Invasive Weed in Asia
Author(s): Harry C. Evans and Carol A. Ellison
Source: Mycologia, Vol. 97, No. 4 (Jul. - Aug., 2005), pp. 935-947
Published by: Mycological Society of America
Stable URL: http://www.jstor.org/stable/3762243
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Mycologia, 97(4), 2005, pp. 935-947.
? 2005 by The Mycological Society of America, Lawrence, KS 66044-8897
The biology and taxonomy of rust fungi associated with the neotropical vine
Mikania micrantha, a major invasive weed in Asia
Asia during the early part of the 20th century
(Choudhury 1972, Holmes 1982, Waterhouse 1994)
and by the 1930s it was much used in Malaysia as
ground cover in plantation crops such as oil palm
and rubber (Thompson 1939, Parker 1972). Nevertheless by the 1960s M. micrantha had assumed the
status of a problematic weed in plantation crops, particularly of tea in northeastern India and rubber and
oil palm in southeastern Asia (Parker 1972, Holm et
al 1977, Waterhouse 1994, Gogoi 2001). The weed
has spread more recently to southwestern India,
where it is invading both natural and planted forests,
as well as subsistence and cash crops at the forest
interface (Nair 1988, Evans 1998, Sankaran and
Sreenivasan 2001), and also to China (Zhang et al
2004).
Biological control, specifically the classical approach involving the introduction of co-evolved natural enemies from the region of origin of the exotic
weed target, was suggested initially as a management
strategy for M. micrantha by Parker (1972). Later
Cock (1982) undertook surveys for insect natural enemies in the Neotropics. A thrips species (Liothrips
mikaniae) from Trinidad was introduced subsequently into the Solomon Islands and Malaysia but this
failed to become established (Cock et al 2001), and
attention has now focused on evaluating the biocontrol potential of fungal natural enemies (Ellison
2004). Evans (1987), using literature and herbarium
records, had compiled an inventory of the pathogenic fungi associated with weedy species of Mikania.
This was followed by field surveys in southern Brazil
(Barreto and Evans 1995), from which it was concluded that several rust species warrant further investigation as potential classical biocontrol agents for
introduction into the Paleotropics where these coevolved rusts are absent. The present paper reports
on the biology and taxonomy of the rust fungi encountered on M. micrantha during exploratory surveys in the Neotropics.
Harry C. Evans1
Carol A. Ellison
CABI Bioscience, Silwood Park, Ascot, BerkshireSL5
7TA, UK
Abstract: Three microcyclic rust species were collected during surveys of the perennial asteraceous
vine Mikania
micrantha
(Eupatorieae:
Asteraceae)
throughout its native range in the Neotropics but
were absent in its invasive range in Asia. The commonest
species,
Puccinia
spegazzinii with brown te-
lioid telia, occurred wherever M. micrantha was
found in South and Central America including the
Caribbean
island of Trinidad.
Dietelia portoricensis,
with occasional vestigial spermogonia and grayishwhite to pale yellow columnar aecioid telia, was collected only in Costa Rica; while D. mesoamericanasp.
nov., apparently restricted to Mesoamerica, can be
distinguished by its abundant, yellowish-orange, fertile spermogonia, yellow to pale brown telial columns, larger teliospores, and 4-spored rather than 2spored metabasidia. The fact that all three species
share a fundamentally similar symptomatology suggests a common origin.
Key words: applied mycology, classical biological
control, Dietelia mesoamericana sp. nov., Dietelia portoricensis, mile-a-minute weed, Puccinia spegazzinii,
systematics
INTRODUCTION
Mikania micrantha H.B.K. (Eupatorieae. Asteraceae) is
a perennial, sprawling vine with a wide distribution
in the Neotropics, which extends from Mexico to Argentina (Holmes 1982). Within this native range it is
restricted mostly to riparian habitats, typically occurring around the margins of rivers, lakes and marshy
terrain and is rarely weedy or invasive (Cock 1982,
Barreto and Evans 1995). In sharp contrast, throughout its exotic palaeotropical range, M. micranthajustifiably has earned the common name of mile-a-minute weed (Holm et al 1977). The plant probably was
introduced into a number of botanical gardens in
MATERIALSAND METHODS
Field collection.-Surveys were conducted from 1996-1999
throughout the native range of M. micrantha in tropical
and subtropicalAmerica. Samples of rust-infectedplants
were collected and initiallystored in a plant pressfor transport to the UK. Part of each samplewas kept as a voucher
Accepted for publication 22 June 2005.
1
Corresponding author. E-mail: h.evans@cabi.org
935
936
MYCOLOGIA
specimen for deposit in Herb. IMI and part for infection
studies. However it was discovered that the rust species infecting M. micrantha lost viability during drying, which necessitated transporting living, rust-infected plants directly to
the UK for the pathogenicity and specificity studies. The
method described below gave the greatest success.
Mikania micrantha readily roots at a node when in contact with soil and produces upright shoots or "plantlets."
Newly infected plantlets (ca. 10 cm tall), typically with only
chlorotic spots and pre-erumpent pustules, were selected
within a rust-infected patch. The "runner" was cut ca. 2 cm
from the plantlet, on both sides, and all extraneous leaves
and soil were removed. The roots were wrapped in a damp
tissue before being placed in a small plastic bag, which was
tied loosely around the stem, and then enclosed within a
bigger, self-sealing bag, which was inflated and sealed to
form a protective vacuum or bubble around the leaves.
Plants were able to survive at least 2 wk and the rust pustules matured during this period. When only mature pustules were available, both healthy and infected plantlets
were mixed together and, invariably, the former became
infected during transit to the UK.
Greenhousestudies.-Plants used for rust-inoculation studies
were propagated from cuttings and grown in a 1:1 mixture
of general purpose, peat-based potting compost and John
Innes No. 2 soil-based compost (J. Arthur Bower, Lincoln,
UK). Pre- and postinoculated plants were maintained in an
air-conditioned, quarantine greenhouse chamber set at 22
+ 5 C, with a 12 h light/dark cycle (metal halide, full spectrum, light intensity range of 8000-13 000 lux). Test plants
were grown on plant-support frames and pruned to stimulate fresh shoot production. The inoculation procedure
was: shoot meristems were sprayed with a fine mist of distilled water, then mature, rust-infected material was suspended ca. 5 cm above the shoot apices using plant ties
attached to the support frame. The plants were transferred
to a dew chamber (Mercia Scientific, Birmingham, UK) set
at 20 C, for 24 h and returned to quarantine for daily observation.
TAXONOMY
following rust species and
Description of rusts.-The
their variants were delimited during the study and
the descriptions are based on fresh material obtained
from greenhouse inoculations, as well as from dried
field collections.
Dietelia portoricensis (Whetzel & Olive) Buritica &J.F.
Hennen, Flora Neotropica 24: 15. 1980.
FIGS. 1-7; 8C, D; 9B, C
= EndophylloidesportoricensisWhetzel & Olive, AmJ Bot
4:51. 1917.
= Cronartium
portoricensis (Whetzel
& Olive)
Sacc. &
Trotter, Syll Fung 23: 851. 1925.
=Aecidium expansum Arthur, Mycologia 7:317. 1915.
Spermogonia rare, epiphyllous, subepidermal, type
4, effete, honey-colored to brown, globose, 110-150
[pm. Telia aecioid, subepidermal, amphigenous, on
leaves, petioles and stems; sori 3-6 mm diam on
leaves; sori on petioles and stems often coalescing
and occurring in grossly swollen areas; comprising
few to many, strongly erumpent, yellow aecioid cups
producing grayish-white to pale yellow waxy columns
or horns, up to 1-1.5 mm X 240-320 JLm, with an
outer peridium of interlocking, rhomboidal, strongly
x
verrucose, thick-walled (4-6 iLm) cells, (25-)30-42
16-25 rm. Teliospores unicellular, hyaline to subhyaline, smooth, thin-walled, guttulate, globose to ovoid
X (13-)15-19
(15-)17-23(-25)
Vm; in long persistent chains; often, but not always, separated by prominent, hyaline, smooth, guttulate, ovoid to ellipsoidal
intercalary cells, 5-9 X 10-16 [Lm. Metabasidia long,
<200 Jim, usually producing only two sterigma-bearing cells separated by a densely guttulate, sterile cell.
[Lm); basidSterigmata prominent, long (<60-100
to ovoid,
iospores hyaline, smooth, subglobose
x 8-12 fim.
(12-)14-17
Material examined.-COSTA RICA. LIMONPROV.:Rio Madre de Dios, Siquirres, on Mikania micrantha, 17 May 1998,
C.A. Ellison & R.H. Reeder(IMI 393068); same locality and
host, 6 Sep 1998, H. C. Evans (IMI 393072). TRINIDAD AND
TOBAGO. NORTHERNRANGE:Aripo, on Mikania guaco
Humb. & Bonpl., 11 Jun 1945, H. Owen (IMI 6316).
Commentary. At the Costa Rican locality M. micrantha was heavily attacked by Puccinia spegazzinii,
often with telia from both species intermixed on the
same leaf, which caused initial confusion over the
identity and interrelationships of the rust species involved. This was clarified during infection studies in
the UK.
Chlorosis occurred ca. 12-13 d after inoculation
and the aecioid telia appeared 8-10 d later (FI(;S. 1,
2). Spermogonia were observed only rarely and these
always were effete (FIG. 3). As the telial columns matured under high humidity the peridial wall turned
outward and upward exposing the teliospores that
germinated to produce extremely long basidia with
thickened, crozier-like tips with two, heavily pigmented cells typically separated by a smaller sterile cell
(FIG. 6). Sterigmata develop only from the former
cells and thus only two basidiospores are formed per
basidium (FIG. 7). Sterigmata occasionally were observed to branch, and in such cases 3 or 4 basidiospores may be produced.
Dietelia portoricensis has been recorded on various
Mikania species, including M. micrantha, from Colombia (Kern et al 1933, Buritica and Pardo-Cardona
1996) and Trinidad (Arthur 1922a), as well as from
Puerto Rico by Stevenson (1975), who described it as
common in Central America, the West Indies and
937
EVANS AND ELLISON: RUST FUNGI FROM MIKANIA weed
South America. This has not been our experience in
the Neotropics, nor that of others, who also have
failed to record it from Costa Rica (Arthur 1918),
Cuba (Arthur andJohnston 1918, Urban 1990), Brazil (Barreto and Evans 1995), Barbados and the
Windward Islands (Baker and Dale 1948), Jamaica
(Dale 1955) and Mexico (Le6n-Gallegos and Cummins 1981). Examination of the specimen from Trinidad (IMI 6316) showed that teliospore morphology
corresponds well with that of the Costa Rican material, however, the peridial cells are verruculose, rather than strongly verrucose, and smaller.
In the original description by Olive and Whetzel
(1917), who erected the monotypic genus Endophylloides Whetzel & Olive to accommodate this species,
spermogonia were considered to be "not formed"
and the peridial cells were said to be inconspicuous.
Thirumalachar (1949) re-examined the material on
M. cordifolia (L.f.) Willd. from Puerto Rico and his
sections revealed that the peridial cells are persistent
on the spore columns, although he described them
as thin and evanescent, which is not the case for the
Costa Rican material (FIGS.4, 7). He distinguished
Endophylloidesfrom Endophyllum, not by the absence
of an evident peridium-one of the generic characteristics used by Olive and Whetzel (1917)--"but by
the occurrence of columnar telia." In Endophyllum
the aecioid telia are pulverulent. Cummins (1959)
also recognized the genus Endophylloides but compared it to the genus Dietelia, with which he suggested it even may be synonymous. Later Buritica and
Hennen (1980) concluded that Endophylloidesshould
be reduced to synonymy with Dietelia because the
presence or absence of intercalary cells was neither
a critical nor a consistent character. Thus Cummins
and Hiratsuka (1983, 2003) subsequently amended
the generic description of Dietelia: "with intercalary
cells basally but often not seen."
Romero and Carri6n (1998) reported D. portoricensis for the first time from Mexico. However, in
their description, teliospore dimensions are given as
18-32 X 14-24 ,Im, whereas those of the type are
much smaller, 15-20 X 12-15 IJm (Olive and Whetzel
1917). After further collections in Mexico in the
same localities listed by Romero and Carri6n (1998),
and subsequent comparison with the Costa Rican material of D. portoricensis, as well as with herbarium
material from Guatemala deposited in Herb. IMI as
D. portoricensis, it was concluded that both the Mexican and Guatemalan rusts are sufficiently distinct to
justify separation at the species level.
Dietelia mesoamericana H.C. Evans et C.A. Ellison,
sp. nov.
FIGS. 8A, B; 9A; 10-18
Spermogonia
amphigenia,subepidermalia,typus4, insignitus, laxe gregariavel dense sparsa,mellea vel lutea; globosa ad subglobosa, (80-)120-180(-200) X (70-)100-160
(-180) jLm.Teliaaecioid, amphigenia,subepidermalia;in
folia insidentibuset in greges (4-6 mm diam) plus minusve
regularesdispositisvel sparsisin nervisfoliorum;in caulibus
et petiolis greges incrassatasaepe valde elongata,matricum
deformantia;cylindrica,cerinea vel fulva,in cornua vel columnae ceracea formentibus,ad 1.5-2 mm longa vel 160300(-450) ,umlata. Cellulaperidialiafirme conjunctae,hyalinis vel subhyalinus verruculosa vel verrucosa, parietibus
2-3.5 jLm,angulatae,ellipsoidiavel rhomboidia,(19-)28catenulatae,unicel38(-42) x (14-)17-25 im. Teliosporae
lulatae, subhyalinae,laeve, tenuitunicatae,guttulatae,obovoideae vel ellipsoideae, 23-30 x 14-21 ,im; cellula intercalaria ellipsoideus, 5-9(-11)
X 10-13 JLm.Basidiosporae
obovoideae-ellipsoideae,9-12 X 6.5-9 jLm.
HOLOTYPUS:
MEXICO. VERACRUZ:Laguna Es-
condida, Los Tuxtlas, ex Mikania micrantha, 14 Sep
1998, H.C. Evans, A. Romero & G. Carri6n (IMI
393070).
PARATYPI: MEXICO. VERACRUZ:Laguna Escon-
dida, Los Tuxtlas, ex Mikania micrantha, 3 Feb 1997,
R. Segura & M. Martinez (IMI 393066); La Mancha,
ex Mikania micrantha, 9 Sep 1998, H.C. Evans & A.
Romero (IMI 393073).
TAMAULIPAS:Nuevo Morelos,
ex Mikania micrantha, 12 Sep 1998, H.C. Evans &
A. Romero (IMI 393071).
Etymology. Mesoamericana, pertaining to its Mesoamerican distribution.
Spermogonia amphigenous, subepidermal, type 4,
prominent, arranged in groups in swollen, chlorotic
areas, or densely scattered on leaves, petioles and
stems, yellowish-orange to honey-colored, globose to
X (70-) 100-160
subglobose, (80-) 120-180(-200)
(-180) txm. Spermatia abundant, clavate to ovoid, 46 X 2-2.5 jLm. Telia aecioid, amphigenous, subepidermal: on leaves in circular sori (4-6 mm) or densely scattered along midribs and veins; on petioles and
stems densely grouped and extensive, often accompanied by hypertrophy of the tissues; cylindrical, as
waxy, yellow to tawny brown columns or horns, up to
1.5-2.0 mm X 160-300(-450) jim, encased in a persistent peridium of interlocking cells. Peridial cellshyaline to subhyaline, verruculose to verrucose, thickwalled (2.0-3.5 jLm), ovoid to ellipsoidal to rhomX (14-) 17-25 jLm. Telioboidal, (19-)28-38(-42)
spores catenulate, unicellular, subhyaline, smooth,
thin-walled, guttulate, obovoid to ellipsoidal, 23-30
X 14-21 iLm;separated by persistent intercalary cells,
ellipsoid, 5-9 (-11) X 10-13 jLm.Metabasidia hyaline,
smooth, 120-150 X 7-8 jim, densely staining in upper third and 4-celled, each cell producing a prominent often long (up to 60 jLm)sterigma. Basidiospores
hyaline, smooth, obovoid to ellipsoid, 9-12 X 6.5-9
Pxm.
MYCOLOGIA
938
0
U
4"~
~~~
t'
.
\
EVANSAND ELLISON:RUST FUNGIFROMMIKANIAweed
Other material examined as Dietelia portoricensis, on Mikania sp.: GUATEMALA.ZARAPA
DEPT.:Los Amates, 15 Mar
1905, WA. Kellermanex Herb. Arthur49476 (IMI55440).
MEXICO. VERACRUZ:
Catemaco, Playa Vicente, 22 Oct 1996,
M.K. Seier (IMI 393079).
Commentary.Chlorosis typically appeared 7-8 d after inoculation when prominent, swollen lesions
formed on both the upper and lower leaf surfaces,
as well as on the petioles. Clusters of orange spermogonia developed 15-19 d after inoculation, which
imparted a shiny or glistening appearance due to the
formation of spermatial droplets (FIG. 10). In contrast to D. portoricensis, however, the subsequent appearance of the telial initials was delayed and the yellow spore columns took <40 d to reach maturity
(FIGS. 11-13). In the field in Mexico spermogonial
pustules, particularly those on the petioles and stems,
frequently were effete and heavily parasitized by a
species of Tuberculina (FIG. 19). This initially caused
severe problems in trying to establish pure cultures
of the rust in the greenhouse in the UK. Only by
regular and judicious brushing of the newly emerging parasitized pustules with 70% alcohol, to remove
the powdery clumps of reddish-brown to purple conidia (FIG.20), followed by repeated inoculations using healthy telia, were clean rust cultures eventually
obtained.
A further six rust species have been reported on
New World Mikania spp., five of which have twocelled telioid telia and belong to Puccinia (Barreto
and Evans 1995), while the other, Uromycesmikaniae
Viegas, has unicellular
telioid teliospores
and an ae-
cidial stage (Viegas 1945). Of the six Dietelia spp. described from the Neotropics (Buritica and Hennen
1980) only two species, D. aequatoriensis (Syd.) Bur-
itica & J.F. Hennen and D. portoricensis, have telial
columns. The former can be distinguished by its
smaller, verrucose teliospores. D. mesoamericana can
be distinguished readily from D. portoricensis by the
consistent presence of fertile spermogonia and the
significantly longer, obovoid to ellipsoidal teliospores. In addition the telial columns or horns of D.
mesoamericanahave a distinctly yellow to pale brown
appearance in fresh material contrasting with the
grayish-white columns of D. portoricensis. Separation
of the two species is made easier, of course, by working with living cultures. For example the prominent
939
spermogonia of D. mesomericana, densely covering
the inoculated leaves, are particularly distinctive and
diagnostic. Moreover the germination process can be
followed and this has allowed for an additional separation character: the metabasidia of D. portoricensis
being predominately 2-spored while those of D. mesoamericana are consistently 4-spored.
Differences in peridial cell morphology between
the Costa Rican material of D. portoricensis and the
holotype of D. mesoamericana(IMI 393070) appeared
initially to be significant. However the peridial cells
of the Guatemalan specimen (IMI 55440), originally
assigned to D. portoricensis (Herb. Arthur), are thickwalled and verrucose, resembling those of D. portoricensis (ex Costa Rica) (FIGS.7, 8D), while the peridial cells of the Trinidadian material (IMI 6316) are
thinner-walled and verruculose, similar to the D. mesoamericana holotype (FIG. 8B). However one of the
Mexican paratypes of D. mesoamericana(IMI 393071)
had an intermediate form. It is concluded therefore
that the morphology of the peridial cells is too variable to be a reliable character, and this may be influenced by the position of the cells within the spore
column or the condition of the specimen. In fresh
greenhouse material telial columns are prominent,
<2 mm in length (FIGS. 12-16); while in field-collected herbarium specimens, these columns are
much reduced or degraded due to weathering and/
or damage in the plant press.
Observations of rust cultures suggest that the telial
columns of D. portoricensisare more prone to sloughing from the infected plant than those of D. mesoamericana. Indeed microscopic examination (FIGS. 4,
15, 16) reveals that the peridium of the latter species
is a much more coherent structure and is less prone
to fracture. In addition detached telial columns of D.
portoricensis placed directly on the leaf surface have
been observed to produce modified sterigmata or infective hyphae rather than basidiospores that lead to
normal infection. The basidiospores of D. mesoamericana are released readily from the intact telia, resulting in heavy infection in greenhouse inoculations,
whereas those of D. portoricensis frequently are
trapped in the peridium, perhaps due to their large
size (FIGS.7, 18), and, as a consequence, the resulting infection is less severe.
Further differences between the two species relate
FIGS.1-7. Macro-and micromorphology of Dietelia portoricensis, IMI 393068 ex Costa Rica. 1, 2. Lower leaf surface and
petiole of Mikania micrantha, with grayish-white, aecioid telial columns, 3 wk after inoculation. 3. Cross section of effete
spermogonia. 4. Cross section of telial column, with peridial wall. 5. Chain of unicellular teliospores separated by intercalary
cells. 6. Metabasidium with two sterigmata separated by prominent sterile cell (arrow). 7. Mature metabasidium producing
two basidiospores only, note thick-walled, verrucose, peridial cells (arrows). Bars: FIGS.3, 4=60 iLm;5-7=10 inm.
940
MYCOLO(IA
EVANS AND ELLISON: RUST FUNGI FROM MIKANIA weed
941
B
A
Fig. 9. Teliospores germination of Dietelia spp. A. D. mesoamericana(IMI 393070), shoNwingdevelopment of four sterigmata.
B. D. porto7icensis(IMI 393068), shoNwingtwo sterigmata separated by heavily-pigmented sterile cell. C. D. portoricensis,more
advanced stage of teliospore germination showing basidiospore formation. Bars: F(;s. A, B = 20 pLm;C = 10 pLm.
to their biology, and specifically the symptomatology
observed during the greenhouse inoculations. Thus
D. portoricensishas a relatively long biotrophic phase
(ca. 2 wk) before the first symptoms of chlorosis appear, after which development of the telia is rapid.
In D. mesoamericana,however, chlorotic pustules are
visible within 1 wk but this is followed by a long maturation period (ca. 5-6 wk in total) during which
fertile spermogonia and then the telial columns de-
velop. This is interpreted as evidence of the functional role of the spermogonia within the life-cycle of D.
mesoamericana, which is clearly vestigial in D. portoricensis.
We were intrigued that the 7uberculina mycoparasite was recorded only on D. mesoamericana and
proved to be common in the field and troublesome
in the greenhouse. It was never found on D. portoricensis, or on P spegazzinii, and failed to become es-
Fli(. 8. Comparative morphology of aecioid telial stage of Dietelia spp. A, B. D. mesoameircana (IMI 393070), showing
obovoid-ellipsoidal teliospores (A) and small, mainly ovoid-rhomboidal, verruculose, peridial cells (B). C, D. D. portoricensis
(IMI 393068),
showing globose-ovoid
teliospores
(C) and rhomboidal,
verrucose,
peridial cells (D). Bar = 10 Jim.
942
MYCOLOGIA
-
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943
EVANS AND ELLISON: RUST FUNGI FROM MIKANIA weed
tablished on either of these two rusts in the greenhouse, despite proximity to heavily-parasitized D.
mesoamericana. Lutz et al (2004) have shown that
Tuberculina spp. cluster as a sister group of Helicobasidium within the Urediniomycetes and have a
unique cellular interaction with the haploid stages of
rusts. This association was posited to have a sexual
basis, having evolved from a modified mating interaction (Bauer et al 2004). This suggests therefore
that D. mesoamericanacolonizes its host in the haploid phase, hence the need for functional spermogonia; while the other two species colonize in the
diploid phase, and either totally lack spermogonia (P.
spegazzinii), or if present these are effete (D. portoricensis).
Without this fundamental knowledge of the biology, Buritica and Hennen (1980) expanded the species concept of D. portoricensis,as envisaged by Olive
and Whetzel (1917) and probably based on the Guatemalan material, to include the presence of fertile
spermogonia and teliospores significantly larger than
those originally described. Faced with this amended
species description, Romero and Carri6n (1998) had
no option but to include their Mexican collections
within D. portoricensis.
Puccinia spegazzinii De Toni in Saccardo, Syll. Fung.
7:704. 1888.
FIGS. 21-23
Teliospores2-celled, occasionally3-celled, linear-oblong
to clavate, (35-)40-65(-72) X (10-) 12-18 pxm,obtuse or
rounded abovenarrowbelow,slightlyconstrictedat septum;
wall pale yellow to brown, smooth, thin, thickened at apex
(2-3 [pm);pedicel colorless,as long as or longer than spore,
8-10 mmdiam, frequentlyswollen (<14 !zm) below spore.
Metabasidiumhyaline,60-70 X 5-6 Vpm,
becoming swollen
(10-12 Rm), densely staining and guttulatein upper half;
4-celled, each cell producing a fertile sterigma. Basidiosporeshyaline,smooth, obovoid-ellipsoidal,9-13(-15) X 58(-9.5) pLm.
Telial morphology is highly variable among the
strains examined, and the golden-yellow to darkbrown teliospores are embedded in the host tissues
within distinctly raised cushion-like sori, 4-7 mm
diam. These are produced mainly on the lower leaf
surface but also occur on the petioles and stems,
where they typically coalesce, forming elongated pustules, often accompanied by gross hypertrophy of the
underlying tissues (FIG. 21). Such perennial telial
cushions may be hyperparasitized in the field, particularly by species of Eudarluca, the ascostromata of
which may replace the rust tissues (FIGS. 22, 23).
Materialon M. micrantha,host confirmed by molecular
DEPT.:
analysis (Ellison et al 2004). ARGENTINA. MISIONES
Rio Iguassu,13 Jun 2000, H.C. Evans (IMI393078). BRASan Miguel do Anta, 15 Nov 1996, C.A.
ZIL. MINASGERAIS:
Ellison &J. Mauricio (IMI 393060); Marip6, 30 Nov 1996,
C.A. Ellison & H.C. Evans (IMI 393061). COLOMBIA.
CALDASDEPT.: Chinchina, 7 Jul 1996, PS. Baker (IMI
393058). COSTA RICA. LIMONPROV.:Rio Madre de Dios,
Siquirres, 17 May 1998, C.A. Ellison & R.H. Reeder (IMI
393069). ECUADOR. NAPOPROV.:Rio Pucufio, Loreto, 28
Mar 1999, H.C. Evans (IMI 393075). IMBABURA
PROV.:Rio
Mira, Collapi, 22 Mar 1999, H.C. Evans (IMI 393074). NICARAGUA. MATAGALPADEPT.: Selva Negra, Jinotega,
29 Jun
2002, H.C. Evans & R.W. Barreto (IMI 393077). PERU.
Cuzco DEPT.:Pilcopata, 18 Nov 2001, H.C. Evans & R.H.
Reeder (IMI 393076).
SAN MARTINDEPT.: Tabolosos,
30 Jan
1997, H.C. Evans, (IMI 393065). TRINIDAD & TOBAGO.
Parrylands, La Brea, Nov-Dec 1996 (composite sample),
H.C. Evans & M. Morais (IMI 393062-4); St Patrick, Jul
1997, M.J.W. Cock (IMI 393067); Arima, Blanchisseuse, Jul
1996, M.J.W. Cock (IMI 393057).
Additional material examined, host identity not confirmed
by DNA sequence analysis. The host is given according to
the voucher specimen, however, because M. scandens is confined to North America (King and Robinson 1987), it is
more than probable that the true host is M. micrantha:
BRAZIL. PARA:Santa Isabel, on M. micrantha, 6 Nov 1963,
FC. Albuquerque (IMI 135722).
Rio DE JANEIRO:Barra de
SaoJoao, on M. micrantha, 19 Aug 1989, R. W Barreto (IMI
345385). COSTA RICA, San Jose, on M. scandens, 23 Dec
1924, H. Sydow (IMI 55443); Oratina, 30 Dec 1915, on M.
micrantha, collector unknown (IMI 55444). GRENADA (W.
Indies). on M. micrantha, 6 Feb 1946, R.E.D. Baker (IMI
55441). PANAMA. Bocas del Toro, on M. micrantha, 2 Feb
1921, M.A. Carleton (IMI 55442). ST. VINCENT (W. Indies). Dorset Hill, on M. micrantha, 26 Dec 1971, C. Critchet
(IMI 163360). TRINIDAD & TOBAGO. NORTHERNRANGE:
Siparia, on M. scandens, 3 Oct 1947, W.T.Dale (IMI 32155).
FIGS.10-18. Macro- and micromorphology of Dietelia mesoamericana,IMI 393070 ex Mexico. 10. Prominent, yellow, fertile
spermogonia developing on upper leaf surface of Mikania micrantha, 18 d after inoculation; inset of spermogonial group
with spermatial droplets developing within raised, chlorotic pustules. 11. Cross section of erumpent, fertile spermogonium,
showing trichogynes and spermatia. 12. Young telial columns developing along swollen petiole 25 d after inoculation. 13,
14. Mature, yellow telial columns formed on chlorotic, swollen pustules on leaves and petioles 35-40 d after inoculation that
later become necrotic (FIG. 14). 15, 16. Cross section of telial columns showing early stage with prominent, basal meristem
(arrow) and compact peridial wall (FIG. 15); and mature stage (Fig. 16), 40 d after inoculation. Germinating teliospores
showing early metabasidial stage. 18. Maturing metabsidium with four sterigmata; inset of basidiospores, compare FIG. 7.
Bars: 11 = 30 ,um; 15, 16 = 115 pLm;17, 18 = 10 pm.
944
MYCOLOGIA
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EVANS AND ELLISON: RUST FUNGI FROM MIKANIA weed
Commentary. This species first was described on
Mikania scandens var. periplocifolia ( = M. periplocifolia Hook. & Arn.; King and Robinson 1987) from
Argentina, and also on M. cordifolia, and has a number of synonyms (Barreto and Evans 1995). Arthur
(1922b) described P. spegazzinii on several Mikania
species from North America, including M. cordifolia,
although it was never observed on this host during
the present surveys, when it was recorded only on M.
micrantha in Argentina, Brazil, Costa Rica, Ecuador,
Nicaragua, Peru and Trinidad.
Puccinia spegazzinii is a microcyclic rust, producing
only telioid teliospores and basidiospores. Spermogonia, aecia and uredinia are unknown in the field
(Arthur 1922b, Le6n-Gallegos and Cummins 1981,
Barreto and Evans 1995), and greenhouse inoculations have confirmed this reduced life-cycle.
DISCUSSION
Without authoritative data on both the taxonomy
and biology of a potential biocontrol agent, permission to introduce and release this agent will not normally be granted by the relevant quarantine body in
the importing country (FAO 1996). Thus, taxonomy
is an essential component of any classical biological
control program, and this is very much the case with
the rusts associated with Mikania micrantha that are
described here.
This paper reports on three, morphologically distinct rust species occurring on M. micrantha in the
Neotropics. However, Viegas (1945) recorded a further species associated with this host in the state of
Paraiba, north-east Brazil. This species, Puccinia mikania-micranthaeViegas, is apparently also microcyclic with only teliospores, described as predominately
unicellular, rarely two-celled, which would seem to fit
the generic concept of Uromycesrather than Puccinia.
His illustrations clearly depict a unique species,
which was not encountered during the present study,
despite the intensive surveys mainly in central and
southern Brazil. It may be that P. mikania-micranthae
has a distribution limited to north-east Brazil.
Puccinia spegazzinii was subsequently selected for
host range and pathogenicity screening, which took
3 yr to complete, and these results will be reported
FIGS. 19-23.
Fungal hyperparasites
945
elsewhere. A fully-tested pathotype of this rust from
Trinidad is being held in quarantine in India, prior
to release in the Western Ghats (south-west India)
and Assam (north-east India); and a pathotype from
Argentina, now in quarantine in Beijing, is close to
being released in Guangdong Province, Southern
China. However, recent screening of the new species
Dietelia mesoamericana,has shown that this rust fungus may be the preferred agent for some of the biotypes of M. micrantha currently on an invasive front
in both Asia and Australasia.
Whether the three species delimited here are more
closely related than their morphology suggests is currently being investigated using molecular techniques
in order to test the theory, based on their biology,
that all three share a common origin or ancestry.
These microcyclic taxa may have speciated from a
full-cycled Puccinia, with a Central American or Caribbean evolutionary center, as they radiated into the
different geographic zones: P. spegazzinii dominating
in South America, while D. portoricensis and D. mesoamericana evolved in the Central American-Caribbean and Mesoamerican regions, respectively.
Cummins and Hiratsuka (2003) used the term endocyclic for life-cycles such as those described here
for Dietelia portoricensisand D. mesoamericana,which
are derived from aecial or uredinial states. However,
since spores of both germinate to produce basidiospores they are teleomorphs and not anamorphs.
Logically, therefore, parental generic names should
be used but, without molecular evidence and based
purely on morphology, this would be speculative.
Buritica and Hennen (1980) elected to place Dietelia
in the tribe Pucciniosireae of the family Pucciniaceae.
Later, however, Buritica and Hennen (1994) considered grouping all endocyclic genera in a separate
family, Endophyllaceae. More recently, Cummins and
Hiratsuka (2003) have elected to place endocyclic
genera close to the families of suspected parental
genera or groups of genera. Thus, Dietelia in their
system is now classified in the family Pucciniosiraceae
and not Pucciniaceae. We believe, however, that molecular data will show that both Dietelia portoricensis
and D. mesoamericanaare closely related to P spegazzinii.
of rusts associated with Mikania
micrantha. 19, 20. Tuberculina
sp. hyperparasitic on,
and replacingtelial sori of Dieteliamesoamericana;in field situationin Mexico (arrows)(FIG.19), and in greenhousesituation
in UK (FIG.20). 21-23. Pucciniaspegazzinii in greenhouse and field situation,showingnon-parasitizedtelial sori developing
on lower leaf surface and in swollen pustuleson petiole, 12 daysafter inoculationwith IMI393976 ex Pilcopata,Peru (FIG.
21); and telia in field ex Tabolosos,Peru (IMI393065), heavilyhyperparasitizedby Eudarlucasp. (FIG.22). Crosssection of
rusted stem showingascostromataof Eudarlucasp. completelyreplacingtelia. Bar = 60 pm.
MYCOLOGIA
946
ACKNOWLEDGMENTS
The assistance of Robert Barreto, Matthew Cock, Gloria
Carri6n, Angel Romero and Ricardo Segura in obtaining
living material is much appreciated. This work was supported by the UK Department for International Development (DFID) within the Crop Pest Research Program
(R6735), and under DEFRA licence No. PHL 182/4869.
LITERATURECITED
Arthur JC. 1918. Uredinales of Costa Rica based on collections by E.W.D. Holway. Mycologia 10:111-154.
.1922a. Uredinales collected by Fred J. Seaver in
Trinidad. Mycologia 14:12-24.
1922b. North American Flora 7:574.
,Johnston JR. 1918. Uredinales of Cuba. Mem Torrey Bot Club 17:97-175.
Baker RED, Dale WT. 1948. Fungi of Barbados and the
Windward Islands. Mycol Pap 25:1-26.
Barreto RW, Evans HC. 1995. The mycobiota of the weed
Mikania micrantha in southern Brazil with particular
reference to fungal pathogens for biological control.
Mycol Res 99:343-352.
Bauer R, Lutz M, Oberwinkler F. 2004. Tuberculinarusts: a
unique basidiomycetous interfungal cellular interaction with horizontal nuclear transfer. Mycologia 96:
960-967.
Buritica P, Hennen JF. 1980. Pucciniosireae (Uredinales,
Pucciniaceae). Flora Neotropica Monogr 24:1-50.
. 1994. Familia Phakopsoraceae (Uredinales)
,
I. Generos anam6rficos y teliom6rficos. Rev Acad Colombiana Cienc Exactas, Fisicas y Nat 19:47-62.
, Pardo-Cardona VM. 1996. Flora Uredineana Colombiana. Rev Acad Colombiana Cienc Exactas, Fisicas
y Nat 20:183-236.
Choudhury AK. 1972. Controversial Mikania (climber)-a
threat to the forests and agriculture. Ind Forest 98:176186.
Cock MJW.1982. Potential biological control agents for Mikania micrantha HBK from the neotropical region.
Tropic Pest Man 28:242-254.
, Ellison CA, Evans HC, Ooi PAC. 2001. Can failure
be turned into success for biological control of mile-aminute weed (Mikania micrantha)? In: Spencer PM,
ed. Proceedings of the 10th International Symposium
on Biological Control of Weeds. Bozeman, USA: Montana State University Press. p 155-167.
Cummins GB. 1959. Illustrated genera of fungi. Minneapolis, USA: Burgess. 150 p.
, Hiratsuka Y. 1983. Illustrated genera of rust fungi.
Revised ed. St Paul, Minnesota, USA: APS Press. 153 p.
. 2003. Illustrated genera of rust fungi. 3rd
ed. St Paul, Minnesota, USA: APS Press. 225 p.
Dale WT. 1955. A preliminary list of Jamaican Uredinales.
Mycol Pap 60:1-21.
Ellison CA. 2004. Biological control of weeds using fungal
natural enemies: a new technology for weed management in tea? IntJ Tea Sci 3:4-20.
, Evans HC, Ineson J. 2004. The significance of in-
traspecies pathogenicity in the selection of a rust pathotype for the classical biological control of Mikania micrantha (mile-a-minute weed) in Southeast Asia. In:
CullenJM, Briese DT, Kriticos DJ, Lonsdale WM, Morin
L, Scott JK eds. Proceedings of the 11th International
Symposium on Biological Control of Weeds. Canberra,
Australia: CSIRO Entomology. p 102-107.
Evans HC. 1987. Fungal pathogens of some subtropical and
tropical weeds and the possibilities for biological control. Biocon News Info 8:7-30.
. 1998. Major Indian weeds of neotropical origin and
the possibilities for collaborative biocontrol projects.
In: Ferrar R, Muniappan P,JayanthJP, eds. Proceedings
of the 4th International Workshop on Biological Control and Management of Chromolaenaodorata. Guam,
USA: Agricultural Experiment Station, University of
Guam. p 55-62.
FAO. 1996. International Standards for Phytosanitary Measures. Code of Conduct for the Import and Release of
Exotic Biological Control Agents. Rome, Italy:Secretariat
of the International Plant Protection Convention. 21 p.
Gogoi A. 2001. Status of Mikania infestation in northeastern India: management options and future research
thrust. In: Sankaran KV, Murphy ST, Evans HC, eds.
Alien weeds in moist tropical zones, banes and benefits.
Peechi, Kerala, India: Kerala Forest Research Institute.
p 77-79.
Holm LG, Plucknett DL, Pancho JV, Herberger JP. 1977.
The world's worst weeds: distribution and biology. Honolulu, Hawaii: University Press of Hawaii. 609 p.
Holmes WC. 1982. Revision of the Old World Mikania
(Compositae). Botan Jahres Beitr Systematik 103:211246.
Kern FD, Thurston HW, Whetzel HH. 1933. Annotated index of rusts of Colombia. Mycologia 25:448-480.
King RM, Robinson H. 1987. Genera of the Eupatorieae.
Monogr Syst Bot Missouri Bot Gard 22:1-581.
Le6n-Gallegos H, Cummins GB. 1981. Uredinales de Mexico (Vol.1). Mexico City: Secretariat de Agricultura y
Recursos Hidraulicos. 151 p.
Lutz M, Bauer R, Begerow D, Oberwinkler F. 2004. Tuberculina: rust relatives attack rusts. Mycologia 96:614-626.
Nair KNN. 1988. Mikania micrantha H.B.K.-a noxious
weed in the forests of Kerala. Evergreen 20:13-14.
Olive EW, Whetzel HH. 1917. Endophyllum-likerusts of Porto Rico. AmJ Bot 1:44-52.
Parker C. 1972. The Mikania problem. PANS 18: 312-315.
Romero A, Carri6n G. 1998. Primer registro de Dietelia portoricensis (Uredinales) en Mexico. Rev Mex Micol 14:
53-55.
Sankaran KV, Sreenivasan MA. 2001. Status of Mikania infestation in the Western Ghats. In: Sankaran KV, Murphy ST, Evans HC, eds. Alien weeds in moist tropical
zones, banes and benefits. Kerala, Peechi, India: Kerala
Forest Research Institute. p 67-76.
Stevenson JA. 1975. The Fungi of Puerto Rico and the
American Virgin Islands. Contr Reed Herb 23:1-743.
Thirumalachar MJ. 1949. Critical notes on some plant rustsII. Sydowia 5:23-29.
EVANSAND ELLISON:RUST FUNGIFROMMIKANIA weed
Thompson A. 1939. Notes on plant diseases in 1937-1938.
Malayan Agric J 27:86-98.
Urban Z. 1990. A contribution to the rust fungi (Uredinales) of Cuba. Rep Tottori Mycol Inst 28:37-56.
Viegas AP. 1945. Alguns fungos do Brasil 4-Uredinales. Bragantia 5:1-144.
947
Waterhouse DF. 1994. Biological control of weeds: southeast Asian prospects. Canberra, Australia: ACIAR.
302 p.
Zhang LY, Ye WH, Cao HL, Feng HL. 2004. Mikania micrantha H.B.K. in China-an overview. Weed Res 44:
42-49.