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Agricultural Research Center, Jiroft, Iran; University of Tehran, Karaj, Iran; University of Mazandaran, Sari, Iran
Nattrassia mangiferae, the Cause of Die-Back and Trunk Cankers
of Ficus religiosa and Branch Wilt of Psidium guajava in Iran
M. R. M
IRZA
ˆEE
1
,M.M
OHAMMADI
2
and H. R
AHIMIAN
3
Authors’ addresses:
1
Jiroft Agricultural Research Center, AREEO, Ministry of Agriculture, Jiroft, Iran 78615–115;
2
Department
of Plant Pathology & Entomology, College of Agriculture, University of Tehran, Karaj, Iran 31584–11167;
3
Department of Plant
Protection, College of Agriculture, University of Maˆ zandaran, Saˆ ri, Iran (correspondence to M. Mohammadi. E-mail:
mohammadi_mojtaba@hotmail.com and mohamadi@chamran.ut.ac.ir; present address: Agricultural Biotechnology Laborat-
ories, Department of Biochemistry, Microbiology and Immunology, 40 Marie Curie Private, University of Ottawa, Ottawa, ON,
K1N 6N5, Canada; E-mail: mojtaba_mohammadi@science.uottawa.ca)
With 5 figures
Received August 31, 2001; accepted January 29, 2002
Keywords: Ficus religiosa,Nattrassia mangiferae,Psidium guajava, branch wilt, die-back, Iran, trunk canker
Abstract
In 2000, in the Jiroft region, south-eastern Iran, a fungus
subsequently identified as Nattrassia mangiferae was
isolated from both Ficus religiosa, which showed branch
die-back and elongated cankers in trunks, and Psidium
guajava (guava) trees, which showed branch die-back.
The pathogenicity of the fungus was demonstrated by
fulfilling Koch’s postulates. These diseases are a poten-
tial threat to the citrus industry and P. guajava
production in the region. This is the first report of
N. mangiferae inciting die-back and trunk cankers on
F. religiosa and die-back on P. guajava.
Introduction
Nattrassia mangiferae (arthric state: Scytalidium
dimidiatum), previously known as Hendersonula toruloi-
dea and Dothiorella mangiferae, has a wide host range,
and causes diseases under favourable climatic conditions
especially high humidity and elevated temperatures
(Jayasinghe and Silva, 1994). Hendersonula toruloidea
was originally described as a pathogen of deciduous
fruit trees in Egypt (Nattrass, 1933). The fungus has
since been reported to cause cankers and wilt on a wide
range of species including apricot (Calavan and Wallace,
1954), almond, apple and grapevine (Natour and
El-Haideri, 1967), pistachio and pomegranate in Iran
(Aminaee and Ershad, 1993), Eucalyptus, mulberry,
pear and rubber (Jayasinghe and Silva, 1994), citrus,
walnut, the common fig (Ficus carica), Ficus benghalen-
sis (Giha, 1975) and Ficus sp. (Paxton et al., 1964).
This article describes the symptom development and
identification of the cause of a fungal disease in the
Jiroft region of P. guajava and F. religiosa, an orna-
mental and a shade tree widely grown in southern Iran.
Materials and Methods
Fungal isolation
Infected tissues at the advancing interface of infection
in tree bark were removed, cut in small pieces, washed
in running tap water, surface-sterilized with 1%
(v/v) sodium hypochlorite for 2 min and then washed
three times in sterile distilled water before placing
them on potato dextrose agar (PDA). The Petri plates
were incubated at 30 ± 2C. After incubation for
3–4 days, fungal growth appeared around the margins
of tissue pieces. The mycelium was transferred to
PDA slants and single spore cultures obtained. A total
of 100 spores were examined microscopically from
each fungal isolate. To induce formation of fruiting
bodies, sterile apple shoot tips were placed on PDA
and, 24 h later, each isolate was placed in the centre
of the plate near the tips and kept at 30 ± 2C for
1 month.
Pathogenicity test
An in situ pathogenicity test was done in duplicate on
three branches of two separate trees from each host
plant species and three inoculation sites on the trunk of
a single F. religiosa tree in mid-summer. Two fungal
isolates were used for each plant species. Tissue inocu-
lations were made in wounds created by pushing a
heated knife into the tree at sites previously washed with
sterile distilled water and then inserting agar discs
(5 mm diameter) bearing the fungus in the arthric state.
A control wound approximately 30 cm from each
inoculation point received only an agar disc. Inoculated
and control wounds were covered with transparent
adhesive tape to maintain humidity. Alternatively,
unpunctured bark was inoculated with fungal mycelia,
J. Phytopathology 150, 244–247 (2002)
2002 Blackwell Verlag, Berlin
ISSN 0931-1785
U. S. Copyright Clearance Centre Code Statement: 0931–1785/2002/5005–0244 $ 15.00/0 www.blackwell.de/synergy
and inoculated sites were covered with moistened sterile
cotton plugs.
Individual branch segments (30 cm long ·2–3 cm
wide with attached leaves) from both hosts were also
inoculated as described above and incubated in a moist
growth chamber at 35C for 10 days with a 12 h
photoperiod (Matheron and Sigler, 1994).
Results
During a survey of F. religiosa and P. guajava in the
early summer of 2000 in south-eastern Iran, a serious
disease characterized as die-back of branches and
cankers of trunks was observed on F. religiosa. Most
of the damage occurred on branches where the bark had
cracked and peeled off thereby exposing a sooty layer of
fungal spores (Fig. 1). Another symptom of the disease
was elongated cankers associated with yellowish gum
exuding from the bark of trunks (Figs 2 and 3).
Symptoms on P. guajava were sudden wilting of
branches followed by bark discoloration from dark
grey to black without exposure of any sooty layer of
fungal spores (arthrospores) (Figs 4 and 5). A fungus
Fig. 1 A branch of Ficus religiosa showing a black sooty layer of spore
masses of Nattrassia mangiferae (bfi). Note the complete defoliation
of branches
Fig. 3 A trunk of F. religiosa tree displaying cankers with longitudinal
cracks(afi)
Fig. 2 A trunk of F. religiosa with
canker exuding gum (afi)
Effects of Nattrassia mangiferae on Ficus religiosa and Psidium guajava in Iran 245
with the characteristics of N. mangiferae was isolated on
to PDA from such tissues.
The fungus grew readily on PDA, forming a white
colony consisting of superficial, immersed, branched,
septate mycelia that later became pale to dark oliva-
ceous and produced chains of one- to two-celled
(mostly one-celled) spores. The conidia were rather
variable in shape and size, being either elongated
(average 5 lm·7.5–10 lm diameter) or spherical
(5–7.5 lm). This anamorph (Scytalidium dimidiatum)
formed in all fungal isolates examined. The fungus
produced pycnidia on PDA and on inoculated apple
shoot-tips 25 days after incubation. Pycnidia were
eustromatic, erumpent, spherical (average 140 lmin
length), and pycniospores were hyaline, 0–2 septate,
average 5 lm·12.5 lm. The optimal temperature for
mycelial growth was 29–34C.
Wounded branches and trunks were infected after
tissue inoculation. No symptoms developed in wounded
and unwounded control treatments, and no fungi were
recovered. Nattrassia mangiferae was re-isolated from
the edges of 10-day-old inoculated tissues. Symptom
development in F. religiosa was slower than in
P. guajava. On the basis of the above-mentioned
characteristics, the fungus was identified as Nattrassia
mangiferae (H. & P. Syd.) Sutton and Dyko.
Discussion
The taxonomic features of the fungus described in this
study were consistent with those reported by Wilson
(1949), Calavan and Wallace (1954) and Sutton and
Dyko (1989). We conclude that, as the inoculated
unpunctured sites remained healthy, N. mangiferae is a
wound parasite of both F.religiosa and P. guajava.
These results are in agreement with those of Natour and
El-Haideri (1967). Sunburn is known to predispose host
trees to attack by N.mangiferae (Giha, 1975; Jayasinghe
and Silva, 1994). The sunny and hot conditions in the
Fig. 4 A branch of Psidium guaj-
ava, exhibiting die-back and defo-
liation (cfi)
Fig. 5 In situ pathogenicity test on
a branch of P. guajava; inoculation
site (afi); edge of healthy and
infected tissue (bfi); distance
showing symptoms and disease
progression 8 days after incubation
at 40C(cfid)
246 M
IRZA
ˆEE
et al.
Jiroft region are favourable for the pathogen to invade
orange (Mirzaˆ ee, unpublished data), F. religiosa and
P. guajava trees. Recently, Taheri et al. (2000) demon-
strated that, under laboratory conditions, propiconazole
was a more effective fungicide against N.mangiferae
than copper oxychloride, zineb, benomyl and mancozeb.
None of the fungicides, however, controlled the disease
on lemon cultivar Lisbon in orchards in Khuzestan
province, Iran.
As F. religiosa is close to the citrus orchards in the
Jiroft region, we recommend that infected tissues should
be removed from F. religiosa to avoid spread of
inoculum.
Acknowledgements
We thank Dr J. Ershad, a senior research scientist at the Mycology
Division, Plant Pest and Disease Research Institute, AREEO, the
Ministry of Agriculture, Tehran, Iran, for the identification of fungal
isolates and Mr A. Ahmadpour for the photographs.
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Effects of Nattrassia mangiferae on Ficus religiosa and Psidium guajava in Iran 247
