scholarly journals First Report of Canker Disease Caused by Botryosphaeria parva on Cork Oak Trees in Italy

Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 324-324 ◽  
Author(s):  
B. T. Linaldeddu ◽  
A. Franceschini ◽  
J. Luque ◽  
A. J. L. Phillips
Keyword(s):  
Elongation Factor ◽  
Quercus Suber ◽  
Cork Oak ◽  
Width Ratio ◽  
Canker Disease ◽  
First Report ◽  
Oak Trees ◽  
Mycelial Plug ◽  
Pathogenicity Tests ◽  
Length Width

A survey was carried out in the spring of 2003 to study the fungi associated with declining trees in a cork oak (Quercus suber L.) forest located in Sassari Province, Sardinia, Italy (40°52′N, 9°01′E) at an altitude of 150 m (above sea level). Several isolates obtained from live twigs and branches showing sunken necrotic bark lesions were identified as Fusicoccum parvum Pennycook & Samuels (teleomorph Botryosphaeria parva Pennycook & Samuels). Neither pycnidia nor ascomata were observed on the symptomatic samples collected. On potato dextrose agar (PDA) at 25°C, the isolates developed an aerial and compact mycelium, initially white but becoming gray after 4 to 6 days, and produced pycnidia after 1 month on sterile cork oak twigs placed on the surface of PDA. Conidia from culture were hyaline, ellipsoidal to fusiform, externally smooth, thin walled, nonseptate, 12 to 19 (15.5) × 5.5 to 8.5 (6.5) μm, with length/width ratio of 2.4 ± 0.1 (mean ± standard error). Identity was confirmed by analysis of the nucleotide sequences of the internal transcribed spacer (ITS) from the rRNA repeat and the translation elongation factor 1-alpha (EF1-α), as done elsewhere (1,4). BLAST searches at GenBank showed a high identity with reference sequences (ITS: >99%; EF1-α: 100%). Representative sequences of both regions were deposited at GenBank (ITS: Accession No. DQ487157; EF1-α: Accession No. DQ487158). Pathogenicity tests were carried out on seven 2-year-old cork oak seedlings maintained in a greenhouse at 14 to 26°C with the B. parva strain CBS 119937 obtained in this study. A mycelial plug (3 to 4 mm2) taken from the margin of an actively growing colony on PDA was put in a shallow wound made by a scalpel on the basal part of the stem of each seedling. Sterile PDA plugs were placed into similar wounds on three control seedlings. The inoculation points were wrapped in Parafilm to retain moisture for 1 week. After 4 weeks, all seedlings inoculated with B. parva died and showed a collapse of the stem cortical tissues associated with dark brown discolorations and vascular necrosis measuring 10.9 ± 0.4 cm. No symptoms were visible in the control seedlings. The pathogen was reisolated from all the inoculated seedlings, thus fulfilling Koch's postulates. The results confirm the virulence of this fungus and point to its possible involvement in the aetiology of cork oak decline. B. parva is a cosmopolitan, plurivorous pathogen causing disease in several hosts of economic importance, such as grapevine (3), kiwi (2), and Eucalyptus spp. trees (1). To our knowledge, this is the first report of B. parva causing canker disease on cork oak trees. References: (1) A. Gezahgne et al. S. Afr. J. Bot. 70:241, 2004. (2) S. R. Pennycook and G. J. Samuels. Mycotaxon 24:445, 1985. (3) A. J. L. Phillips. Phytopathol. Mediterr. 41:3, 2002. (4) B. Slippers et al. Mycologia 96:83, 2004.

scholarly journals First Report of Pestalotiopsis clavispora and Pestalotiopsis spp. Causing Postharvest Stem End Rot of Avocado in Chile

Plant Disease ◽  
2011 ◽  
Vol 95 (4) ◽  
pp. 492-492 ◽  
Author(s):  
A. L. Valencia ◽  
R. Torres ◽  
B. A. Latorre
Keyword(s):  
Its Region ◽  
The United States ◽  
Persea Americana ◽  
Width Ratio ◽  
Maturity Stage ◽  
Basal Cells ◽  
First Report ◽  
Pathogenicity Tests ◽  
Length Width ◽  
White Mycelium

Avocado (Persea americana) production in Chile has increased to more than 33,500 ha. Chilean avocadoes are sent to markets 15 to 45 days away by overseas transport to the United States, Europe, and Asia. Although apparently healthy avocadoes were harvested in 2009, a 10 to 14% incidence of stem end rot appeared after 15 days of cold storage. Symptoms appeared as small, irregular, brown lesions on the peel at the stem end. Lesions enlarged rapidly, became sunken and soft, eventually comprising the entire fruit as ripening progressed. A white mycelium often developed around the stem cavity. A dark brown necrosis of the pulp was observed that comprised a big part of the pulp as the fruits matured. Isolations were performed from ‘Hass’ avocadoes that developed stem end rot after fruits were kept in humid chambers for 15 days at 5°C plus 6 days at 20°C (n = 50) to simulate a transport period from Chile to U.S. markets or from diseased fruits (n = 50) kept for 15 days at 20°C. Fruits were surface disinfected for 60 s in 75% ethanol, and small pieces of tissue were excised from the margins of the pulp lesions and then plated onto potato dextrose agar (PDA) plus 1 ml/liter of Igepal CO-630 (Sigma-Aldrich, Atlanta, GA) (MPDA). Fungal colonies that developed on PDA were white and cottony, turning slightly yellow after 15 days. Black acervuli appeared after 15 days at 20°C. Conidia (n = 40) were fusiform, (22.2) 27.0 to 30.4 × (6.3) 7.0 to 9.8 μm with a length/width ratio of 3.4 ± 0.4. All isolates had five-celled conidia. Apical and basal cells were colorless, while the three median cells were dark brown. Conidia had one basal appendage (9.3 ± 3.3 μm) and two to four long apical appendages (34.5 ± 6.9 μm). On the basis of colony and conidia morphology, most of these isolates were initially identified as Pestalotiopsis clavispora (G.F. Atk) Steyaert, but other nonidentified species of Pestalotiopsis were also found (3). Identification was confirmed by amplifying and sequencing the internal transcribed spacer (ITS) region of rDNA using ITS1/ITS4 primers of P. clavispora isolate PALUC-12 (Accession No. HQ659767). A BLAST search of the NCBI database showed that isolate PALUC-12 had 100% homology with P. clavispora (No. EU342214.1). Pathogenicity tests were conducted on surface-disinfected (75% ethanol, 30 s) fruits by placing agar pieces (3 mm in diameter) from 7-day-old cultures and a 20-μl drop of 106 conidia/ml on wounded and unwounded stem cavities and equatorial area of five avocado fruits of ‘Hass’, per isolate tested, at the commercial maturity stage. Inoculated fruits were placed in moist chambers at 25°C for 10 days. Necrotic lesions resembling symptoms that occurred in storage fruits were observed on wounded fruits. No symptoms were observed on unwounded fruits inoculated in the equatorial zone. However, unwounded fruits inoculated in the stem cavity developed a slight necrosis probably because of undetectable wounds made at harvest. Koch's postulates were confirmed after the reisolation of P. clavispora and Pestalotiopsis spp. from diseased fruits. P. versicolor has been reported in South Africa (1), but to our knowledge, this is the first report of P. clavispora causing stem end rot of avocado. P. clavispora has been reported on blueberry in Chile (2). References: (1) J. M. Darvas and J. M. Kotzé. Phytophylactica 19:83, 1987. (2) J. G. Espinoza et al. Plant Dis. 92:1407, 2008. (3) E. F. Guba. Monograph of Pestalotia and Monochaetia. Harvard University Press, Cambridge, MA, 1961.

scholarly journals First Report of Canker Disease Caused by Neofusicoccum australe on Eucalyptus and Pistachio in Spain

Plant Disease ◽  
2008 ◽  
Vol 92 (6) ◽  
pp. 980-980 ◽  
Author(s):  
J. Armengol ◽  
D. Gramaje ◽  
A. Pérez-Sierra ◽  
E. Landeras ◽  
R. Alzugaray ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Elongation Factor ◽  
Stem Canker ◽  
Malt Extract ◽  
Northern Spain ◽  
Internal Transcribed Spacer Region ◽  
Canker Disease ◽  
First Report ◽  
Inoculation Site ◽  
Mycelial Plug

In 2005 and 2006, dieback and branch cankers were observed in 12-year-old Eucalyptus globulus Labill. plantations in Gijón (northern Spain) and a 20-year-old pistachio (Pistacia vera L.) plantation in Constantí (northeastern Spain). Isolations were made from symptomatic branches. Small pieces of necrotic tissues were surface sterilized for 1 min in 1.5% NaOCl and plated onto malt extract agar amended with 0.5 g L–1 streptomycin sulfate. Plates were incubated at 25°C in the dark and all growing colonies were transferred to potato dextrose agar (PDA). A Neofusicoccum sp. was consistently isolated from necrotic tissues of both host species. On PDA at 25°C, isolates developed a moderately dense mycelium, initially with a pale yellow pigment diffusing into the medium but becoming olivaceous gray after 5 to 6 days. Pycnidia were produced on sterile eucalyptus and pistachio twigs placed on the surface of water agar after 1 month. Conidia were hyaline, fusiform, aseptate, with granular contents. Conidia from eucalyptus isolates measured (22.5–) 25.4 (–28.1) × (5–) 6.2 (–7.5) μm, (n = 40) and (20.0–) 23.6 (–28.0) × (6.5–) 7.1 (–8.0) μm, (n = 40) from pistachio isolates. Isolates were identified as Neofusicoccum australe (Slippers, Crous & M.J. Wingf.) Crous, Slippers & A.J.L. Phillips (1,2). DNA sequences of the rDNA internal transcribed spacer region (ITS), part of the beta-tubulin (BT2), and part of the translation elongation factor 1-alpha (EF1-α) genes from isolates CBS 122027 (pistachio) and CBS 122026 and CBS 122025 (eucalyptus) were used to confirm the identifications through BLAST searches in GenBank. Representative sequences of all studied regions were deposited in GenBank (ITS: EU375516 and EU375517; BT2: EU375520; EF1-α: EU375518 and EU375519). Pathogenicity tests were conducted on 8-month-old eucalyptus seedlings and 2-year-old pistachio plants with the three N. australe strains mentioned above. A mycelial plug taken from the margin of an actively growing colony of each isolate was put in a shallow wound (0.4 cm2) made with a scalpel on the stem of each plant. Inoculation wounds were wrapped with Parafilm. Controls were inoculated with sterile PDA plugs. Ten replicates for each isolate and plant species were used, with an equal number of control plants. Plants were maintained in a greenhouse at 25°C. After 3 weeks, all eucalyptus seedlings showed leaf wilting, stem canker, and pycnidia formation around the inoculation site. No foliar symptoms were observed in pistachio plants after 3 months, but depressed cankers variable in size and pycnidia formation developed around the inoculation site. Vascular necroses that developed on the inoculated plants were 10.2 ± 1.2 cm long in eucalyptus and 6.4 ± 1.6 cm long in pistachio, significantly greater than their respective controls (P < 0.01). There were no significant differences in necrosis lengths among the three N. australe isolate inoculations, irrespective of the inoculated host. These results point to a high susceptibility of eucalyptus to N. australe. No symptoms were visible in the control seedlings and no fungus was isolated from them. The pathogen was reisolated from all inoculated plants. To our knowledge, this is the first report of N. australe causing canker disease on eucalyptus and pistachio trees in Spain. References: (1) P. Crous et al. Stud. Mycol. 55:235, 2006. (2) B. Slippers et al. Mycologia 96:1030, 2004.

scholarly journals First Report of Anthracnose on Boehmeria nivea Caused by Colletotrichum higginsianum in China

Plant Disease ◽  
2011 ◽  
Vol 95 (10) ◽  
pp. 1318-1318 ◽  
Author(s):  
X. X. Wang ◽  
J. Chen ◽  
B. Wang ◽  
L. J. Liu ◽  
X. Huang ◽  
...  
Keyword(s):  
Leaf Spot Disease ◽  
Width Ratio ◽  
Plant Leaves ◽  
Climate Chamber ◽  
First Report ◽  
Boehmeria Nivea ◽  
Colletotrichum Higginsianum ◽  
Pathogenicity Tests ◽  
Length Width ◽  
Average Size

Ramie (Boehmeria nivea (L.) Gaud) anthracnose is regarded as one of the most widely spread and devastating diseases of ramie. This disease is most severe during warm and humid conditions. In China, ramie anthracnose is found in approximately 10,000 ha, with yield losses averaging 20% and ranging as high as 55% in some fields (3). In September 2010, typical anthracnose symptoms were observed in cultivated fields near Xianning, HuBei Province, China. Lesions on diseased leaves were initially small, scattered, bluish white, and water soaked. As the disease progressed, irregular spots developed on the leaves and the spots turned gray in the center with a brown margin. The diameter of the lesions was approximately 1 to 3 mm. Initially, lesions on the stems were fusiform and then expanded, causing the stem to break. Leaf and stem tissue adjacent to and including lesions were surface disinfected in 0.1% sodium hypochlorite and then planted on potato dextrose agar (PDA) plus oxalic acid to inhibit bacterial growth. The plates were incubated at 25°C for 3 to 5 days until the appearance of pink spore masses with numerous dense clusters of black setae. On PDA, the fungus initially produced gray colonies with an orange conidial mass and then the colonies turned black after 5 days. Spores were single celled, colorless, straight, oval, obtuse at both ends, 10.0 to 20.0 × 3.0 to 5.0 μm with an average size of 15.8 ± 2.4 × 4.6 ± 0.4 μm, and a length/width ratio of 3.47 ± 0.62. The setae were dark brown, 1 to 3 septa. These morphological traits corresponded to Colletotrichum higginsianum Sacc (1). The ITS1, 5.8S, and ITS2 sequences with primers ITS1 and ITS4 of this fungus (GenBank Accession No. JF830783) were 99% similar to sequences of multiple isolates of C. higginsianum (GenBank Accession Nos. GU935872 and AB042303). In pathogenicity tests, both sides of ramie plant leaves from 10-day-old, 30-cm high plants were sprayed with conidial suspensions (1 × 106 conidia/ml) of a representative fungal isolate. This experiment was repeated three times. Inoculated plants were incubated in an artificial climate chamber with a 12-h photoperiod at 25 to 28°C and a relative humidity of 90%. Three days after inoculation, brown spots and water-soaked lesions were observed on all inoculated leaves, but no symptoms were seen on water-treated control plants. Koch's postulates were fulfilled by the reisolation of C. higginsianum from diseased leaves. C. higginsianum is known to cause anthracnose leaf spot disease on many cultivars of Brassica and Raphanus spp., but there have been no reports on it causing ramie anthracnose. C. boehmeriae Sawada and C. gloeosporioides Penz are known to be the agents of ramie anthracnose (2,3). To our knowledge, this is the first report of C. higginsianum causing anthracnose of ramie in China and in the world. References: (1) A. J. Caesar et al. Plant Dis. 94:1166, 2010 (2) R. M. Li and H. G. Ma. J. Plant Prot. 20:83, 1993. (3) X. X. Wang et al. Plant Dis. 94:1508, 2010.

scholarly journals The First Report of Downy Mildew Caused by Peronospora belbahrii on Sweet Basil in Greenhouses in the Czech Republic

Plant Disease ◽  
2014 ◽  
Vol 98 (11) ◽  
pp. 1579-1579 ◽  
Author(s):  
I. Šafránková ◽  
L. Holková
Keyword(s):  
Czech Republic ◽  
Downy Mildew ◽  
Width Ratio ◽  
Specific Sequence ◽  
The Czech Republic ◽  
First Report ◽  
Sweet Basil ◽  
Potted Plants ◽  
Length Width ◽  
Necrotic Spots

Sweet basil (Ocimum basilicum L.) is an aromatic plant that is cultivated as a pot plant in greenhouses or in fields in the Czech Republic. The plants are intended for direct consumption or for drying. In April of 2012, the first large chlorotic from the middle necrotic spots occurred gradually on leaves of pot plants O. basilicum cv. Genovese in greenhouses in Central Bohemia. The characteristic gray to brown furry growth of downy mildew appeared on abaxial surfaces of leaves in the place of chlorotic spots within 3 to 4 days. The infested leaves fell off in the late stages of pathogenesis. The infestation gradually manifested itself in ever-younger plants and in July, cotyledons and possibly the first true leaves were already heavily infected and damaged and these plants rapidly died. The plant damage reached 80 to 100%, so it was necessary to stop growing the plants in the greenhouse at the end of July. The causal agent was isolated and identified as Peronospora belbahrii Thines by means of morphological and molecular characters (2,3). Conidiophores were hyaline, straight, monopodial, 280 to 460 μm, branched three to five times, ended with two slightly curved branchlets with a single conidia on each branchled tip. The longer branchlets measured 13 to 24 μm (average 18.2 μm), the shorter one 4 to 15 μm (average 9.7 μm). Conidia were rounded or slightly ovoid, from brownish to dark brownish, measured 22 to 31 × 20 to 28 μm (length/width ratio 1.2). A pathogen-specific sequence was detected with the help of the pathogen ITS rDNA specific primers in symptomatic leaves (1). DNA from plant tissues was isolated using the DNeasy plant Mini Kit (Qiagen, Germany) following the standard protocol. PCR was performed using KAPA2G Robust HotStar kit (Kapa Biosystems, United States) according to the conditions recommended in Belbahri et al. (1). The specific products were visualized by electrophoresis through 1.5% agarose gels. Leaves of 20-day-old potted plants O. basilicum ‘Genovese’ were inoculated by spraying with 5 × 105 conidia/ml of the pathogen. Each pot contained 10 plants. Sterilized distilled water was applied to control plants. Plants were covered with polyethylene bags during the entire incubation period to maintain high humidity, and kept at a temperature of 22 to 24°C. Typical disease symptoms appeared on leaves 5 to 9 days after inoculation. Control plants were symptomless. P. belbahrii was re-isolated from the lesions of inoculated plants, thus fulfilling Koch's postulates. Downy mildew on sweet basil was reported in countries in Africa, Europe, and South and North America (4). To our knowledge, this is the first report of downy mildew on sweet basil in the Czech Republic. References: (1) L. Belbahri et al. Mycol. Res. 109:1276, 2005. (2) Y.-J. Choi et al. Mycol. Res. 113:1340, 2009. (3) M. Thines et al. Mycol. Res. 113:532, 2009. (4) C. A. Wyenandt et al. HortScience 45:1416, 2010.

scholarly journals Linking Cork to Cork Oak Landscapes: Mapping the Value Chain of Cork Production in Portugal

2021 ◽  
Vol 5 ◽  
Author(s):  
Irene Holm Sørensen ◽  
Mario Torralba ◽  
Cristina Quintas-Soriano ◽  
José Muñoz-Rojas ◽  
Tobias Plieninger
Keyword(s):  
Value Chain ◽  
Global Scale ◽  
Quercus Suber ◽  
Agroforestry Systems ◽  
Cork Oak ◽  
Oak Trees ◽  
Cork Production ◽  
Central Portugal ◽  
Characteristic Features ◽  
Farming Landscapes

Traditional farming landscapes in South and Central Portugal, known as montados, are affected by global socio-economic and biophysical pressures, putting the sustainability of the systems in jeopardy. Cork oak trees (Quercus suber L.) are characteristic features of these complex agro-silvo-pastoral agroforestry systems, delivering a globally important product, cork. The increasingly distant, global scale of decision making and trade can consequently be observed on the local, landscape, scale. In this study, we use a value chain approach to test the concept that landscape products can ensure sustainable management of the landscape of origin. We interviewed agents—cork producers, intermediaries, industrial transformers, and winemakers—about the challenges they perceived in the business and how these were connected to the landscape of origin. We illustrate the network of agents and sub-actors involved in the sector and highlight the most prominent concerns. We conclude that this approach can reveal the major points for determining the future of the montado, and we suggest that collaboration amongst value chain agents can be a pathway to landscape sustainability.

Cork Oak Trees (Quercus suber L.)

2006 ◽  
pp. 113-123 ◽  
Author(s):  
Rubén Álvarez ◽  
Mariano Toribio ◽  
Millán Cortizo ◽  
Ricardo-Javier Ordás Fernández
Keyword(s):  
Quercus Suber ◽  
Cork Oak ◽  
Oak Trees

scholarly journals Factors affecting post-fire regeneration after coppicing of cork oak (Quercus suber) trees in northeastern Algeria

2020 ◽  
Vol 50 (4) ◽  
pp. 371-379
Author(s):  
Salah Eddine Roula ◽  
Rachid T. Bouhraoua ◽  
Filipe X. Catry
Keyword(s):  
Tree Mortality ◽  
Management Practices ◽  
Negative Impact ◽  
Quercus Suber ◽  
Grazing Pressure ◽  
Cork Oak ◽  
Ecological Impacts ◽  
Factors Affecting ◽  
Growing Seasons ◽  
Oak Trees

Wildfires may have serious and long-lasting impacts in Mediterranean Basin oak forests. Although cork oak (Quercus suber L.) is usually considered a highly fire-resistant tree species, post-fire recovery is not guaranteed. We assessed the mortality and regeneration of 729 cork oak trees that burned and were cut in six sites with the objective of identifying the main factors affecting the short- to medium-term post-fire recovery. We used linear mixed models to investigate potential relationships among tree stump status at the end of the second and fifth growing seasons and several tree- and site-level variables. Overall tree mortality in the second year was 44% and was negatively affected by bark thickness and positively affected by root exposure, trunk injuries, and diameter, in decreasing order of importance. Between the second and fifth years, mortality increased to 53%, but this increase was only observed in sites with high grazing pressure. Grazing also had a strong negative impact on the growth of basal resprouts, thereby compromising tree recovery. The results give useful information on the need for application of adequate forest management practices (particularly avoiding debarking injuries, soil erosion, and grazing pressure) to increase the resilience of these ecosystems and reduce the negative economic and ecological impacts of wildfires.

scholarly journals First Report of Lasiodiplodia theobromae Causing Dieback of Aquilaria sinensis in Taiwan

Plant Disease ◽  
2013 ◽  
Vol 97 (5) ◽  
pp. 690-690 ◽  
Author(s):  
M.-C. Fan ◽  
H.-C. Yeh ◽  
C.-F. Hong
Keyword(s):  
Uv Light ◽  
Aerial Mycelium ◽  
Molecular Characteristics ◽  
Width Ratio ◽  
Sodium Hypochlorite Solution ◽  
Aquilaria Sinensis ◽  
Lasiodiplodia Theobromae ◽  
First Report ◽  
Tree Survival ◽  
Pathogenicity Tests

Incense trees (Aquilaria sinensis (Lour.) Gilg) belong to a plant family used for alternative medicine in China and the production of wood. In the summer of 2012, at a nursery in Niaosong district, Kaohsiung City, Taiwan, more than 30% of a total of 400 incense trees had dieback symptoms on twigs with leaves attached, leading to eventual death of the entire plant. Symptomatic twigs and trunk pieces from six trees were collected and discolored tissues were excised, surface sterilized in 0.5% sodium hypochlorite solution, rinsed in sterilized distilled water, dried on sterilized filter paper, and then placed in petri dishes containing 2% water agar (WA). The dishes were incubated at room temperature for 1 to 2 days to obtain fungal strains from diseased tissues. The hyphal tips from developing fungal colonies were transferred to potato dextrose agar (PDA, Difco) dishes and placed under UV light (12 h/day) at 30°C. The purified colonies were used as inoculum in the pathogenicity tests. Pathogenicity tests were performed on 2-month-old A. sinensis seedlings, each treatment had three plants. Each plant was wounded by removing bark of the twigs with a disinfected scalpel enough to place a mycelium plug (about 5 × 10 mm2) of 7-day-old fungal isolate on the wound. The inoculated area was wrapped with a wet paper towel and Parafilm. Control plants were treated with PDA plugs. The symptoms described above were observed on inoculated plants 4 to 8 days after inoculation whereas control plants did not show symptoms. Diseased twigs were cut and placed in a moist chamber 21 days after inoculation and conidia oozing from pycnidia were observed. The same fungal pathogen was reisolated from inoculated plants, but not from the control. To identify the pathogen, the fungus was cultured as described above. The colonies were initially white with green to gray aerial mycelium after 5 to 6 days and eventually turned darker. Immature conidia were hyaline and one-celled, but mature conidia were dark brown, two-celled, thin-walled, and oval-shaped with longitudinal striations. The average size of 100 conidia was 25.23 ± 1.97 × 13.09 ± 0.99 μm with a length/width ratio of 1.92. For the molecular identification, the internal transcribed spacer (ITS) region of ribosomal DNA was PCR amplified with primers ITS1 and ITS4 (2) and sequenced. The sequences were deposited in GenBank (Accession No. JX945583) and showed 99% identity to Lasiodiplodia theobromae (HM346871, GQ469929, and HQ315840). Hence, both morphological and molecular characteristics confirmed the pathogen as L. theobromae (Pat.) Griffon & Maubl (1). To the best of our knowledge, this is the first report of L. theobromae causing dieback on Incense tree. This disease threatens tree survival and may decrease the income of growers. References: (1) W. H. Ko et al. Plant Dis. 88:1383, 2004. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, New York, 1990.

Can behavioural differences inPlatypus cylindrus(Coleoptera: Platypodinae) from Portugal and Tunisia be explained by genetic and morphological traits?

2015 ◽  
Vol 106 (1) ◽  
pp. 1-8 ◽  
Author(s):  
A. Bellahirech ◽  
M.L. Inácio ◽  
F. Nóbrega ◽  
J. Henriques ◽  
L. Bonifácio ◽  
...  
Keyword(s):  
Morphological Traits ◽  
Nucleotide Composition ◽  
Quercus Suber ◽  
Genetic Differences ◽  
Cork Oak ◽  
Protective Measures ◽  
Mediterranean Countries ◽  
Oak Trees ◽  
Coi Sequences ◽  
Wood Borer

AbstractPlatypus cylindrusis an important wood borer of cork oak trees (Quercus suber) in the Mediterranean region, namely Portugal, Morocco and Algeria where its presence has drastically increased in the past few decades. On the contrary, the insect is not a relevant pest in Tunisia. The aim of this work is to analyze morphological and genetic differences among Tunisian and Portuguese populations in order to understand their role in the diverse population dynamics (e.g., aggressiveness) of the insect. The information could be used as a novel tool to implement protective measures. Insects were collected from cork oak stands in Tunisia (Ain Beya, Babouch and Mzara) and Portugal (Chamusca and Crato). Morphological traits of female and male mycangial pits were determined, using scanning electron microscopy but no significant differences were found. Genetic differences were analyzed using nuclear (internal simple sequence repeat polymerase chain reaction) and mitochondrial (cytochrome oxidase I (COI)) molecular markers. The results showed a very low level of intraspecific polymorphism and genetic diversity. The alignment of COI sequences showed high percentage of identical sites (99%) indicating a very low variation in nucleotide composition. Other variables related with the ecology of the insect and its associated fungi must be studied for a better understanding of the differences in the insect population's dynamic in Mediterranean countries.

scholarly journals First report of Trichoderma afroharzianum causing seed rot on maize in Italy

Plant Disease ◽  
2022 ◽  
Author(s):  
Martina Sanna ◽  
Massimo Pugliese ◽  
Maria Lodovica GULLINO ◽  
Monica Mezzalama
Keyword(s):  
Rna Polymerase Ii ◽  
Elongation Factor ◽  
Aerial Mycelium ◽  
Light Cycle ◽  
Conidial Suspension ◽  
Ear Rot ◽  
Trichoderma Spp ◽  
Trichoderma Species ◽  
First Report ◽  
Pathogenicity Tests

Maize (Zea mays L.) is a cereal crop of great economic importance in Italy; production is currently of 60,602,320 t, covering 588,597 ha (ISTAT 2021). Trichoderma species are widespread filamentous fungi in soil, well known and studied as biological control agents (Vinale et al., 2008). Seeds of a yellow grain hybrid (class FAO 700, 132 days) were collected in September 2020 from an experimental field located in Carmagnola (TO, Italy: GPS: 44°53'11.0"N 7°40'60.0"E) and tested with blotter test (Warham et al., 1996) to assess their phytosanitary condition. Over the 400 seeds tested, more than 50% showed rotting and development of green mycelium typical of the genus Trichoderma. Due to the high and unexpected percentage of decaying kernels, ten colonies were identified by morphological and molecular methods. Single conidia colonies of one Trichoderma (T5.1) strain were cultured on Potato Dextrose Agar (PDA) for pathogenicity tests, and on PDA and Synthetic Nutrient-Poor Agar (SNA) for morphological and molecular identification. The colonies grown on PDA and SNA showed green, abundant, cottony, and radiating aerial mycelium, and yellow pigmentation on the reverse. Colony radius after 72 h at 30°C was of 60-65 mm on PDA and of 50-55 mm on SNA. The isolates produced one cell conidia 2.8 - 3.8 µm long and 2.1 - 3.6 µm wide (n=50) on SNA. Conidiophores and phialides were lageniform to ampulliform and measured 4.5 – 9.7 µm long and 1.6 – 3.6 µm wide (n=50); the base measure 1.5 – 2.9 µm wide and the supporting cell 1.4 – 2.8 µm wide (n=50). The identity of one single-conidia strain was confirmed by sequence comparison of the internal transcribed spacer (ITS), the translation elongation factor-1α (tef-1α), and RNA polymerase II subunit (rpb2) gene fragments (Oskiera et al., 2015). BLASTn searches of GenBank using ITS (OL691534) the partial tef-1α (OL743117) and rpb2 (OL743116) sequences of the representative isolate T5.1, revealed 100% identity for rpb2 to T. afroharzianum TRS835 (KP009149) and 100% identity for tef-1α to T. afroharzianum Z19 (KR911897). Pathogenicity tests were carried out by suspending conidia from a 14-days old culture on PDA in sterile H2O to 1×106 CFU/ml. Twenty-five seeds were sown in pots filled with a steamed mix of white peat and perlite, 80:20 v/v, and maintained at 23°C under a seasonal day/night light cycle. Twenty primary ears were inoculated, by injection into the silk channel, with 1 ml of a conidial suspension of strain T5.1 seven days after silk channel emergence (BBCH 65) (Pfordt et al., 2020). Ears were removed four weeks after inoculation and disease severity, reaching up to 75% of the kernels of the twenty cobs, was assessed visually according to the EPPO guidelines (EPPO, 2015). Five control cobs, inoculated with 1 ml of sterile distilled water were healthy. T. afroharzianum was reisolated from kernels showing a green mold developing on their surface and identified by resequencing of tef-1α gene. T. afroharzianum has been already reported on maize in Germany and France as causal agent of ear rot of maize (Pfordt et al. 2020). Although several species of Trichoderma are known to be beneficial microorganisms, our results support other findings that report Trichoderma spp. causing ear rot on maize in tropical and subtropical areas of the world (Munkvold and White, 2016). The potential production of mycotoxins and the losses that can be caused by the pathogen during post-harvest need to be explored. To our knowledge this is the first report of T. afroharzianum as a pathogen of maize in Italy.

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