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Incidence of heart rot at pomegranate fruits caused by Alternaria spp. in Cyprus

  • March 2014
DOI:10.5897/AJAR2013.8507
Authors:
Ibrahim Kahramanoglu at European University of Lefke
Ibrahim Kahramanoglu
Serhat Usanmaz at European University of Lefke
Serhat Usanmaz
Izlem Nizam
Izlem Nizam
Izlem Nizam
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Abstract and Figures

During the growing season of 2012, pomegranate growers in Cyprus indicated that they face a troublesome problem causing fruit decays. This study conducted to identify the pathogen causing fruit decays and determine disease incidence in three different pomegranate cultivars in Cyprus. Disease defined as heart rot caused by fungi: Alternaria spp. Incidence of heart rot was determined as 20.31, 14.91 and 9.82% for the cultivars of Acco, Herskovitz and Wonderful, respectively. The considerable variation among susceptibility of cultivars was supposed to be because of differentiation of flower colour, pollen tastes and etc of pomegranate trees.
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Vol. 9(10), pp. 905-907, 6 March, 2014
DOI: 10.5897/AJAR2013.8507
ISSN 1991-637X
Copyright ©2014
Author(s) retain the copyright of this article
http://www.academicjournals.org/AJAR
African Journal of Agricultural
Research
Short Communication
Incidence of heart rot at pomegranate fruits caused by
Alternaria spp. in Cyprus
Ibrahim Kahramanoglu1,2*, Serhat Usanmaz2 and Izlem Nizam2
1Alnar Pomegranates Ltd., Ataturk Ave. 109/1 Guzelyurt, Cyprus, Mersin 10 Turkey.
2European University of Lefke, Faculty of Agricultural Sciences and Technologies, Cyprus, Mersin 10 Turkey.
Received 13 January, 2014; Accepted 20 February, 2014
During the growing season of 2012, pomegranate growers in Cyprus indicated that they face a
troublesome problem causing fruit decays. This study conducted to identify the pathogen causing fruit
decays and determine disease incidence in three different pomegranate cultivars in Cyprus. Disease
defined as heart rot caused by fungi: Alternaria spp. Incidence of heart rot was determined as 20.31,
14.91 and 9.82% for the cultivars of Acco, Herskovitz and Wonderful, respectively. The considerable
variation among susceptibility of cultivars was supposed to be because of differentiation of flower
colour, pollen tastes and etc of pomegranate trees.
Key words: Heart rot, Alternaria spp., pomegranate, transmission.
INTRODUCTION
Pomegranate (Punica granatum L.) plant is known to be
native to central Asia (Morton, 1987). It is reported by
Bevan (1919) that pomegranate plant was grown for
fresh consumption and exportation during early 1900s in
Cyprus. However, there was a decrease in the area of
pomegranate orchards from 1960s to 2007. New
plantations started to be constituted since 2007 with the
alternative crops projects of United States Agency for
International Development (USAID) in Cyprus and total
area of pomegranate orchards close to 100 ha at the end
of 2013. Many pests are causing important damages on
pomegranates. According to Ksentini et al. (2011),
number of pests can reach up to 91 pests in India.
In 2012, an important problem raised at the
pomegranate fields in Cyprus. Growers reported up to
20% damages on the fruits. They reported that inside of
the fruits are becoming black and arils are decaying. It
was a big challenge for the producers and packers where
this disease has no obvious external symptoms. This
disease is known to be heart rot or black heart and there
are some fungi causing this damage: Alternaria spp.,
Aspergillus spp. (Barkai-Golan, 2001), Penicillium
glabrum and Pilidiella granati (Michailides et al., 2010).
Therefore, this research aimed to identify the pathogen
causing heart rot disease and determine disease
incidence in three different pomegranate cultivars in
Cyprus.
MATERIALS AND METHODS
This research performed by collecting data from 13 pomegranate
orchards during the growing season of 2013. Each orchard are
covering at least 1 ha areas where 80% of the each orchard is
demonstrated with Wonderful cultivar, 10% with Acco and 10% with
Herskovitz. All orchards were established by 5 × 3 m distance and
pruned as globe shape with one trunk in 2007. Totally 772.919
*Corresponding author. E-mail: ibrahimcy2004@yahoo.com. Tel: +90 533 847 14 71.
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution
License 4.0 International License
906 Afr. J. Agric. Res.
Figure 1. Abnormal skin color and internal aril decays caused by heart rot.
fruits (Acco: 65.126; Herskovitz: 91.820 and Wonderful: 615.973)
were controlled and packed at the packing house of Alnar
Pomegranates Ltd. Number of damaged fruits by heart rot was
firstly determined by professional workers and noted. Thus
indefinable and/or speculative fruits from outside (by abnormal color
or weight) were cut to determine if disease exists. Fruit samples
from each cultivar were examined at the Biological Control Institute
of Adana, Turkey. Fungi were scratched from fruits and growed
under potato dextrose agar (PDA) medium. Thus the fungi
examined under microscope by Dr. Ercan Canıhoş according to
spores and determined as the Alternaria spp.
Data from the different orchards were used as replication to
calculate means and standart deviation of the studied orchards and
subjected to one-way ANOVA to determine any statistical
differences among species. Mean separations were done by using
the Duncan’s multiple range test at P < 0.05.
RESULTS AND DISCUSSION
Examination of the fruit samples resulted that the fungi
causing fruit decay in pomegranates is Alternaria spp.
The disease is known as heart rot or black heart and is a
major problem in California (Barkai-Golan, 2001). It is
recognized as a postharvest quality problem but the
infection begins in the orchard. It causes decay on
pomegranate arils ranging from sections to all the arils
without external symptoms except for slightly abnormal
skin color and lesser weights than normal fruits (Figure
1). Spores of Alternaria are airborne and found in the soil,
organic materials, weeds, fruit wastes and etc. and
require a vector to bring them to the hosts. Barkai-Golan
(2001) reported that Alternaria spp. enters the fruit during
bloom and early fruit set. Additional research is needed to
establish inoculum dissemination and time and type of
infection in the case of pomegranate orchards.
Results about the incidence of heart rot were found to
be as 20.31, 14.91 and 9.82% for the cultivars of Acco,
Herskovitz and Wonderful, respectively (Table 1). Firstly
it was thought that Acco is a sweet cultivar and this is
why Alternaria is densly affecting it. However, the
sweetness of this cultivar is not related with Total Soluble
Solids (TSS) where TSS of Acco, Herskovitz and
Wonderful is about 18, 17 and 20 Brix, respectively. And,
on the other hand, Alternaria is being transmitted during
flowering stage where there is no fruit and so no sugar.
Alternaria may also be transmitted by pests after fruit set,
but no pest damages determined on fruits. On the other
hand, similar findings indicated by Michailides et al.
(2011) where they reported that Alternaria is generally
hosting pomegranates during flowering or early fruit set.
Therefore, differences between damage degrees on
cultivars can not be because of the diversity of TSS.
Acco and Herskovitz cultivars are early varieties,
ripening about one month before Wonderful cultivar. Thus
it was thought that incidence differentiation may be
because of the earlier flowering of these cultivars. During
flowering, daily observations were performed to determine
if there is significant difference among the flowering dates
of the cultivars. It was found that flowering starts about 6
to 7 days earlier at Acco and Herskovitz cultivars than the
Wonderful cultivar. Flowering starts in February and
continues until May for both cultivars. However, the full
bloom (open flower) dates, where the most transmission
takes place (Michailides et al., 2011), are approximately
equal for all cultivars.
There are some transmission ways for the Alternaria
spp. to the heart of the fruit; these are: wind (Bashen et
al., 1991; Timmer et al., 2003), rain (Chen et al., 2003)
and various pests (ex: pollen beetles [Ceuthorrhynchus
assimilis Payk. (Coleoptera: Curculionoidea)] and seed
pod weevils [Meligethes aeneus Fabricius (Coleoptera:
Nitidulidae)]) (Köhl and van der Wolf, 2005). When
considering present situation, environmental factors, such
as: wind and rain are almost equal for all cultivars where
they are planted together. However, pest occasions can be
vary on different cultivars depending on the flower
characteristics and etc. Some scientific studies reported
that beneficial or pest insects may act as a vector and
transmit fungal pathogens (Dillard et al., 1998; Köhl and
Kahramanoglu et al. 907
Table 1. Incidence of heart rot at different pomegranate cultivars.
Fields Cultivars
Acco (%) Herskovitz (%) Wonderful (%)
F.1 19.75 9.10 9.60
F.2 13.87 6.00 7.86
F.3 12.11 14.60 8.82
F.4 16.85 8.60 9.96
F.5 22.50 20.20 7.78
F.6 20.06 15.90 10.50
F.7 16.09 8.80 8.96
F.8 27.93 12.60 9.64
F.9 20.23 17.00 12.52
F.10 22.02 14.40 11.76
F.11 39.98 27.30 13.84
F.12 19.79 19.40 7.71
F.13 12.85 19.95 8.65
Average* 20.31±7.34a 14.91±5.97b 9.82±1.90c
* Values followed by the same letter or letters are not significantly different at a 5% level (Duncan multiple
range test).
van der Wolf, 2005). Such as, Dillard et al. (1998)
reported that flea beetles (Phsyllotreta cruciferae Goeze
[Coleoptera: Chrysomelidae] can play as a vector of
Alternaria brssicicola in cabbage fields. Another research
by Palou et al. (2013) reported that main causal agents of
wound and latent infections were Penicillium spp. and
Botrytis cinerea on pomegranates. They also indicated
that, in contrast to pomegranate cv. Wonderful, infections
by Alternaria spp. were not present in pomegranate cv.
Mollar de Elche. It is clear from the results and other
studies that the susceptibility of pomegranates to
infection by Alternaria spp. is varying among cultivars.
Since this disease is being transmitted by biotic and/or
abiotic factors, the variation among cultivars’
susceptibility may be because of flower colour, pollen
tastes and etc. Further studies need to be undertaken to
determine the reason of this choice.
ACKNOWLEDGEMENTS
Authors would like to thank the owners of the thirteen
pomegranate orchards and Alnar pomegranates Ltd and
Special thanks go to Dr. Hakan Fidan and Dr. Ercan
Canıhoş for the identification of the fungi.
Conflict of Interests
The author(s) have not declared any conflict of interests.
REFERENCES
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16.
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... For example, Palou et al. [24] observed that the etiology and incidence of pomegranate postharvest diseases, as the rot caused by P. granati, might depend on the environmental characteristics of the growing area, as well as on the conditions in the preharvest, harvest, and postharvest phases. Kahramanoglu et al. [25] stressed the importance of floral morphology and ripening time to explain the susceptibility to heart rot caused by Alternaria spp. on different pomegranate cultivars; Herskovitz cultivar was found to be more susceptible than 'Wonderful' and less than 'Akko'. Furthermore, pomegranate fruit, in the same environmental conditions, displayed a different susceptibility to cracking according to the cultivar [26]; this finding is interesting considering that cracks could help pathogen penetration and spreading. ...
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Transmission of Alternaria brassicicola to Cabbage by Flea Beetles ( Phyllotreta cruciferae )
Article
In 1995 and 1996, flea beetles (Phyllotreta cruciferae) were observed in the field feeding on cabbage plants that were infected with Alternaria brassicicola. Flea beetles were captured in glass vials, etherized, and placed on agar media for isolation of A. brassicicola. In 1995, A. brassicicola was isolated from 13 out of 69 (18.8%) flea beetles in the first test and 38 out of 132 (28.8%) in the second test. In 1996, flea beetles were collected nine times during the growing season, and the isolation frequency increased from 0 to 77% as the crop approached maturity. In another study, flea beetles were collected from a field of A. brassicicola-infected cabbage, enclosed in plastic bags containing potted healthy cabbage plants, and then placed on a shaded greenhouse bench for 6 days. Alternaria leaf spot developed on plants that were infested with the contaminated flea beetles. Feces obtained from flea beetles that fed on cabbage infected with A. brassicicola contained intact and broken conidia of A. brassicicola and undigested pieces of cabbage leaf. The conidia were viable after passing through the flea beetles, as evidenced by their germination on the glass slides used for collecting the feces. Conidia of A. brassicicola were observed by scanning electron microscopy on all parts of flea beetle bodies, including wings, mouthparts, antennae, and legs.
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First report on Virachola livia Klug. (Lepidoptera: Lycaenidae) and its effects on different pomegranate varieties in Tunisia
Article
  • Jun 2011
Virachola livia Klug 1834 (Lepidoptera: Lycaenidae) was detected for the first time in a cultivated pomegranate orchard in Tunisia in 2006 although it may have been causing damage for several years prior to this. During 2006, 5.2% of the total pomegranate fruit produced in Tunisia was infested by this pest. This invasive species was responsible for 52% of fruit rot at Zerkine locality (Gabe`s Governorate). Levels of V. livia infection were shown to vary among nine pomegranate varieties; the Klaii, Mezzi and Garoussi varieties were the most susceptible, whereas Gabsi, Jbeli, Andolsi, Tounsi, Zaghweni and Zehri were more tolerant to this lycaenidae. The authors consider that this is due to female preference.
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Conidial dispersal by Alternaria brassicicola on Chinese cabbage (Brassica pekinensis) in the field and under simulated conditions
Article
This study investigated conidial dispersal in the field, and effects of simulated wind and rain on the dispersal of A. brassicicola on Chinese cabbage (Brassica pekinensis). Spores were sampled using a Burkard volumetric spore sampler and rotorod samplers in a Chinese cabbage crop. Disease incidence in the field was well fitted by a Gompertz curve with an adjusted r2 of >0·99. Conidia of A. brassicicola were trapped in the field throughout the growing season. Peaks of high spore concentrations were usually associated with dry days, shortly after rain, high temperature or high wind speed. Diurnal periodicity of spore dispersal showed a peak of conidia trapped around 10·00 h. The number of conidia trapped at a height of 25 cm above ground level was greater than that at 50, 75 and 100 cm. Conidial dispersal was also studied under simulated conditions in a wind tunnel and a rain simulator. Generalized linear models were used to model these data. The number of conidia caught increased significantly at higher wind speeds and at higher rain intensities. Under simulated wind conditions, the number of conidia dispersed from source plants with wet leaves was only 22% of that for plants with dry leaves. Linear relationships were found between the number of conidia caught and the degree of infection of trap plants.
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Postharvest Diseases of Fruits and Vegetables: Development and Control
  • Jan 2001
  • R Barkai-Golan
Barkai-Golan R (2001). Postharvest Diseases of Fruits and Vegetables: Development and Control. Elsevier, New York (ISBN: 978-0-444-50584-2) P. 418.