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


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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
African Journal of Agricultural
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.
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
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: 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.
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.
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.
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pomegranate (Punica granatum cv. Mollar de Elche) in Spain.
Phytopathologia Mediterranea 52:478-489.
Timmer LW, Peever TL, Solel Z, Akimutsu K (2003). Alternaria diseases
of citrus–Novel pathosystems. Phytopathologia Mediterranea 42:3-
... Each spot consisted of a light green to yellow halo surrounding a necrotic lesion. Ibrahim et al. (2014) reported Alternaria species causes decay on pomegranate arils ranging from section to all the arils without external symptoms except for slightly abnormal skin colour and lesser weight than normal fruits. Faedda et al. (2015) noticed the symptoms of A. alternata on pomegranate fruits cause black rot of arils, which spreads from calyx area, sometimes confined to part of fruit compartments, while the rind remain unaffected. ...
... Suryawanshi et al. (2013) reported that early blight of tomato caused by Alternaria solani was one of the most destructive diseases causing 48 to78 per cent qualitative and quantitative losses in Marathwada region of Maharashtra state. Ibrahim et al. (2014) conducted a roving survey to determine the disease incidence in three different pomegranate cultivars in Cyprus. The disease was defined as heart rot caused by fungi Alternaria spp. ...
Pomegranate is one of the favourite table fruits of tropical and subtropical regions. Among several fungal diseases affecting pomegranate, anthracnose caused by Colletotrichum gloeosporiodes, spot caused by Curvularia geniculata and blight caused by Alternaria alternata and Pestalotiopsis microspora are important. The studies were conducted on Survey for the severity in central dry zone of Karnataka, Cultural and Morphological studies, of pathogens and in vitro and were carried against all these pathogens. Among the different district surveyed highest and lowest per cent disease index were recorded in Tumkur and Hassan district respectively. In growth phase studies C. gloeosporiodes, C. geniculata and P. microspora reached peak on 10th day, whereas A. alternata reached peak on 8th day after inoculation. The conidia of C. gloeosporiodes were hyaline, single celled, with two oil globules and conidia measuring 12.02 to 12.70 µm × 3.5 to 4 µm. Whereas conidia of A. alternata were brown to dark brown colour with 2-8 septations, produced in chains measuring 20 to 80 µm length and 6.4 to 8.5 µm width. The spores of C. geniculata were dark brown, typically geniculate shaped curved with 3 to 4 septate spores. Conidial length varied from 19.71 to 22.35 µm and width of fungus ranges from 5.81 to 6.42 µm and the conidia of P. microspora were spindle or clavette, five celled with three central coloured cells and two hyaline cells and the length of conidia varies from 25.3 to 29.6 µm × 3.2 to 4.3 µm. Based on the above characters the pathogen was morphologically identified. Among the different solid media evaluated potato dextrose agar, oat meal agar and Sabourad’s dextrose agar were found to be best for growth and sporulation. Among the different fungicides evaluated in vitro Propiconazole, Difenconazole, Hexaconazole, Pyraclostrobin, Tebuconazole + Trifloxystrobin, Pyraclostrobin + Epoxiconazole and Propiconazole + Difenconazole were very effective in inhibiting the growth of fungus.
... Arid regions may be more suitable for pomegranate production if the aim is to avoid fungal pathogen diseases, such as heart rot. However, it remains unclear whether the disease is transmitted by abiotic or biotic methods (Kahramanoglu et al., 2014). Management strategies for preventing heart rot in pomegranate are undergoing investigation, and more research is needed to combat this disease that can cause up to 50% fruit loss in commercial orchards (Ezra et al., 2015). ...
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Pomegranate is a drought-tolerant and salt-tolerant crop. Its fruits contain high levels of phytochemicals that have many health benefits. Pomegranate has the potential to be an alternative crop in areas where water availability is limited, such as west Texas. However, more than 500 pomegranate varieties are estimated to exist worldwide, and little is known about which varieties are suitable for growing in the west Texas region. Therefore, the objective of this study was to evaluate the field performance of 22 pomegranate varieties, specifically based on phenology, resistance to sunburn, fruit split, fruit rot (resistance was calculated by subtracting the percent incidence by 100), yield, fruit phytochemicals, and Brix over the course of 3 years from 2016 to 2018. Cold damage, caused by below-freezing temperatures encountered from Nov. 2018 to Feb. 2019, was also evaluated in Apr. 2019. Our results showed significant varietal differences in nearly all response variables measured, indicating that varietal selection is important for pomegranate production for specific regions, such as west Texas. Leaf budding ranged from 47 to 62 days in 2016, 41 to 54 days in 2017, and 49 to 60 days in 2018. Anthesis ranged from 87 to 119 days in 2016, 80 to 94 days in 2017, and 92 to 114 days in 2018. Fruit resistance to split was broad and ranged from 7.3% to 79.1% in 2017 and from 14.2% to 99.7% in 2018. Fruit sunburn resistance ranged from 14.0% to 64.6% in 2017 and from 28.3% to 90.0% in 2018. Fruit heart rot incidence was nominal for all varieties. Total phenolic compound contents of the pomegranate fruit juice ranged from 0.81 to 1.52 mg GAE/mL, and the total antioxidant capacity ranged from 3.44 to 6.81 mg TE/mL. The yield per tree ranged from 1.00 to 7.96 kg in 2017 and from 0.81 to 10.26 kg in 2018. Brix ranged from 12.5% to 17.4% in 2017 and from 13.9% to 18.4% in 2018. Early winter below-freezing temperatures caused different degrees of cold damage; however, 5 of 22 varieties that originated from Russia did not show any cold damage. Results of a hierarchical cluster analysis based on the means of the key response variables of yield and Brix indicated that four varieties (Al-Sirin-Nar, Russian 8, Ben Ivey, and Salavatski) were notable for having both high yield and high Brix.
... 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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Pilidiella granati, also known as Coniella granati, is the etiological agent of pomegranate fruit dry rot. This fungal pathogen is also well-known as responsible for both plant collar rot and leaf spot. Because of its aggressiveness and the worldwide diffusion of pomegranate crops, the selection of cultivars less susceptible to this pathogen might represent an interesting preventive control measure. In the present investigation, the role of polyphenols in the susceptibility to P. granati of the two royalties-free pomegranate cultivars Wonderful and Mollar de Elche was compared. Pomegranate fruit were artificially inoculated and lesion diameters were monitored. Furthermore, pathogen DNA was quantified at 12–72 h post-inoculation within fruit rind by a real time PCR assay setup herein, and host total RNA was used in expression assays of genes involved in host-pathogen interaction. Similarly, protein extracts were employed to assess the specific activity of enzymes implicated in defense mechanisms. Pomegranate phenolic compounds were evaluated by HPLC-ESI-MS and MS2. All these data highlighted ‘Wonderful’ as less susceptible to P. granati than ‘Mollar de Elche’. In the first cultivar, the fungal growth seemed controlled by the activation of the phenylpropanoid pathway, the production of ROS, and the alteration of fungal cell wall. Furthermore, antifungal compounds seemed to accumulate in ‘Wonderful’ fruit following inoculation. These data suggest that pomegranate polyphenols have a protective effect against P. granati infection and their content might represent a relevant parameter in the selection of the most suitable cultivars to reduce the economic losses caused by this pathogen.
... The main fungi results in severe decay in pomegranates after harvest are Botrytis cinerea, Alternaria spp, Aspergillus niger, Colletotrichum gloeosporioides and Cornelia spp (Palou et al., 2013;Kahramanoglu, et al., 2014). The latent spores placed in the fruit calyx during growing season, in general, become visible after harvest and cause high rate losses in cold storage. ...
The combined effects of controlled atmosphere (CA) storage and postharvest ozone treatment on storage life and quality of pomegranate cv. Hicaznar were investigated. Pomegranates were harvested and grouped in three lots. Non-treated first group was used as control. Second group was exposed to ozone (4 ppm) gaseous for 6h at 5 ºC. Last group was dipped into 0.9 % prochloraz solution (5ºC) for 10 seconds. After treatments, fruit were stored in CA (5 O2 %- 10 CO2 %) conditions at 6 ºC and 90±5 % relative humidity for 5 months. Weight loss, soluble solid content, titratable acidity, respiration rate, fruit skin color, decay incidence, chilling injury and sensory evaluation were determined initially and at one month intervals. Fungicide treatment significantly reduced the weight loss and respiration rate of pomegranates. More decay developed on control fruit than those of ozone and fungicide combinations at the end of storage. Ozone and fungicide treatments gave better results in terms of sensory evaluations compared to control group. No chilling injury incidence was recorded in pomegranate during 5 months. As a result, ozone and prochloraz treatments were effective to prolong the storage life and maintain the post-harvest quality of Hicaznar pomegranate stored in CA conditions.
... The first appearances of Alternata alternata in pomegranate orchards were observed after 2010 in some of the European countries (i.e. Cyprus (Kahramanoğlu et al., 2014), Spain (Berbegal et al., 2014) and Italy (Faedda et al., 2016)). The symptoms included black spots on leaves and fruits as well as chlorosis and premature abscission of leaves. ...
... The first appearance of Alternata alternata in pomegranate orchards observed after 2010 in some of the European countries [i.e. Cyprus (Kahramanoğlu et al., 2014), Spain (Berbegal et al., 2014), Italy (Faedda et al., 2015)]. Azole group fungicides (Tebuconazole and Propiconazole) were reported to be effective to inhibit the pathogen growth (Kumar et al., 2017). ...
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... The disease was identified as black heart of pomegranate caused by A. alternata (Vicent et al., 2016). Black heart is currently present in pomegranate-growing regions in the United States, Greece, Cyprus, Israel, and Italy (Faedda et al. 2015;Kahramanoglu et al. 2014). Recent reports have also identified other Alternaria spp., such as A. arborescens and A. tenuissima, causing black heart of pomegranate (Kanetis et al., 2015;Luo et al., 2017). ...
... Pomegranates are not a new fruit to Cyprus. During the nineteenth and early twentieth century, they were actually one of Cyprus' primary articles of export (Kahramanoglu et al. 2014; Usanmaz 2013, p. 2). The conflict that separated the island ended this trade and pomegranate orchards declined. ...
Climate change is a growing issue for developing countries, as they typically lack the technical and financial inputs to implement the necessary agricultural adaptations. These countries also suffer from the classic collective action problem; although they are able to identify the issue and a potential solution, their individual resources are not substantial enough to enact change. This article discusses north Cyprus' 2006 adoption of pomegranate production and its relationship to climate-related agricultural concerns. We argue that the Turkish Cypriot community would not have been able to start an effective pomegranate agribusiness without third-party financial and technical assistance. As a post-conflict developing community, they lacked the resources necessary to collectivize on their own and initiate crop switching. Thus, Turkish Cypriot farmers needed external resources in order to launch a sustainable development project. The programme was a successful example of sustainable peacebuilding as it required local ownership.
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Citrus is affected by four diseases caused by Alternaria spp. Brown spot of tangerines, leaf spot of rough lemon, postharvest black rot of fruit occur widely in citrus areas of the world and are caused by different pathotypes of A. alternata. Mancha foliar occurs only on Mexican lime in western Mexico and is caused by A. limicola. Tangerine and rough lemon pathotypes produce host-specific toxins that affect membranes and respiration, respectively. Black rot is always associated with wounds and is caused by most citrus-associated isolates of A. alternata that produce endopolygalacturonase. Alternaria brown spot is a serious disease of susceptible tangerines and their hybrids in semi-arid Mediterranean climates as well as in more humid areas. Conidia, produced on lesions on mature and senescent leaves and stems under humid conditions, are dispersed by wind, and infect all juvenile tissues of susceptible cultivars when temperature and leaf wetness conditions are favorable. Commercially acceptable cultivars resistant to brown spot are being developed. Disease severity can be reduced by planting disease-free nursery stock on wider spacings, pruning tree skirts, and reducing irrigation and nitrogen fertilization. However, fungicides such as dithiocarbamates, triazoles, strobilurins, iprodione, or copper fungicides are used in most areas for disease control. A disease-forecasting model, the Alter-Rater, has been developed in Florida to assist in timing fungicide sprays.
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Spain is the largest European Union producer and exporter of pomegranates. More than 85% of Spanish commercial plantings are located in the Elche area (Alicante Province, SE Spain), where cv. Mollar de Elche is the most important cultivar. The incidence and etiology of postharvest pomegranate diseases were determined in local environmental conditions. Commercially-grown pomegranates cv. Mollar de Elche from two orchards were assessed, during two consecutive seasons, for latent and wound pathogens causing postharvest diseases. Healthy pomegranates were either artificially wounded in the rind or surface disinfected and placed in humid chambers at 20ºC for up to 15 weeks. Additionally, decay was periodically assessed on commercially-handled pomegranates stored at 5ºC for up to 27 weeks. The main causal agents of wound and latent infections were Penicillium spp. and Botrytis cinerea, respectively. The same pathogens were also the most frequently isolated from cold-stored fruit, but decay at 5ºC was only significant after 19 weeks. Another relatively frequent pathogen on fruit incubated at 20ºC was Aspergillus niger. Among the fungi isolated, Penicillium expansum, P. sclerotiorum, P. glabrum and Pilidiella granati were pathogenic on inoculated pomegranates, whereas P. minioluteum and Cytospora annulata were not. No decay caused by Alternaria spp. or Colletotrichum gloeosporioides was observed.
Aanbevelingen op basis van een literatuuronderzoek om zaadbesmetting door A. brassicicaola te voorkomen bij biologische zaadproductie van Brassica.
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.
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.
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.
Postharvest Diseases of Fruits and Vegetables: Development and Control
  • 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.