scholarly journals Investigation of oak tree decline in the Auckland region

2007 ◽  
Vol 60 ◽  
pp. 297-303
Author(s):  
M. Braithwaite ◽  
C. Inglis ◽  
M.A. Dick ◽  
T.D. Ramsfield ◽  
N.W. Waipara ◽  
...  

Concern about the poor health of oak trees in Auckland was raised in 2001 An intensive investigation of oak trees showing symptoms of decline (twig and branch dieback epicormic growth trunk cankers bark loss and tree death) was conducted in the Auckland area during 2006 Disease symptoms on trees at 13 sites were documented and samples of leaves stems trunks roots and soil collected Soil samples were tested for the presence of soilborne fungi using baiting techniques Fungi and bacteria from plant tissues and soil were identified using either morphological characteristics biochemical testing or molecular techniques The investigation resulted in a range of fungi and bacteria being identified One fungus new to New Zealand was detected and several new host associations observed No particular organism was implicated as the cause of the oak decline but several fungi and bacteria were likely contributors to the tree decline and death in Auckland

2006 ◽  
Vol 59 ◽  
pp. 132-136 ◽  
Author(s):  
M. Braithwaite ◽  
C.F. Hill ◽  
S. Ganev ◽  
J.M. Pay ◽  
H.G. Pearson ◽  
...  

During 2003 and 2004 fortyfive randomly selected wholesale and retail plant nurseries were surveyed for plant diseases The plant families Agavaceae Annonaceae Arecaceae Bromeliaceae Cycadaceae and Musaceae were targeted Plants were examined in situ for disease symptoms as well as samples being collected for laboratory analyses Fungi were identified using morphological characteristics and where necessary with molecular techniques The survey resulted in a range of fungi being identified from the target plants These fungi ranged from saprophytes to plant pathogens some of which may have undesirable effects on New Zealands biodiversity or economy Many new host/pathogen records were observed and several fungi were detected for the first time in New Zealand This paper presents and discusses the results of these findings


2019 ◽  
Vol 65 (6) ◽  
pp. 743-750 ◽  
Author(s):  
Mohammad Sabernasab ◽  
Samad Jamali ◽  
Alireza Marefat ◽  
Saeed Abbasi

Abstract Oak dieback is one of the most important diseases that presently affects the Kermanshah oak forests (West Iran). During the period from 2013 to 2015, oak trees exhibiting branch dieback were sampled, and fungal colonies resembling those of the Paecilomyces sp. were obtained from diseased tissues. Based on morphology, physiology, and phylogeny of the internal transcribed spacer rDNA, all isolates were identified as Paecilomyces formosus. Pathogenicity tests in vivo were made on 2-year-old seedlings, potted Q. brantii plants, and excised branch sections under controlled conditions. Inoculated seedlings produced characteristic symptoms, and subsequent pathogen recovery confirmed pathogenicity. We determined these to be thermophilic fungi, which may be related to warming and drought. This is the first report of Paecilomyces formosus as the causal agent of Q. brantii dieback in Iran and the world.


Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1114-1114 ◽  
Author(s):  
D. Zhao ◽  
Y. B. Kang

Tree peony (Paeonia suffruticosa Andrews) is a perennial woody deciduous shrub native to China and famous for its beautiful flowers. Starting in early autumn 2010, blighted branches of tree peony were detected in the International Peony Garden in Luoyang. The disease incidence was greater than 10% and disease symptoms included bulb atrophy and twig and branch dieback. Pycnidia were embedded within the bark of diseased branches. They were small, black, ostiolate, and measured 145 to 275 × 140 to 251 μm. Pycnoconidia were single-celled, hyaline or sandy beige, rounded to ellipsoidal, and 3.9 to 10.3 × 2.3 to 7.0 μm. Pure cultures were obtained by plating the pycnoconidia on potato dextrose agar (PDA). In culture, the fungus produced a circular, white to pink colony with pyknotic and linter shaped aerial mycelium. Numerous pycnidia, initially brown and dark at maturity, were embedded in the mycelium, especially in the center of the colony, with a few of them scattered in the edge. The morphological characteristics were consistent with Phoma (2). The ITS1-5.8S-ITS2 region of three isolates were PCR amplified and sequenced with primers ITS1 and ITS4. Sequences (GenBank Accession No. JX885584) showed 99% identity with reference isolates of Peyronellaea glomerata (Corda) Goid (AB470906.1 and HQ380779.1) and Phoma glomerata (Corda) Wollenw. & Hochapfel (EU098115.1). These two species are synonyms (1). To test pathogenicity, nine healthy branches of 3-year-old potted tree peony plants were wound-inoculated with a PDA disk containing pycnidia from an actively growing colony of P. glomerata. Three control branches were inoculated with sterile PDA disks. Each inoculated branch was wrapped in a plastic bag and maintained in a greenhouse at 25 to 28°C. After 3 days, brown patches appeared on inoculated branches and extended by up to 1 cm. Pycnidia identical to those observed in the field and in storage appeared on all inoculated branches 7 days after inoculation. Control branches did not show symptoms. The pathogen was reisolated from inoculated branches, fulfilling Koch's postulates. P. glomerata was reported as the causal agent of withering of flowers and young shoots of grapevines in Yugoslavia (3). To our knowledge, P. glomerata and Botryosphaeria dothidea have always been reported together, causing branch wilting or dieback. To our knowledge, this is the first report of branch blight of tree peony caused by P. glomerata in China. References: (1) M. M. Aveskamp et al. Mycol. Soc. Am. 101:363, 2009. (2) G. H. Boerema et al. Studies in Mycology, 3, 1973. (3) A. Šaric-Sabadoš et al. Atti Ist. bot. Univ. Pavia 18:101, 1960.


Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 876-876 ◽  
Author(s):  
M. Mirabolfathy ◽  
J. Z. Groenewald ◽  
P. W. Crous

The chestnut-leaved oak (Quercus castaneifolia) is native to the Alborz Mountains, including the Golestan Forests, in northern Iran. Trees grow up to 35 (-50) m tall with a trunk up to 2.5 (-3.5) m in diameter. During 2010, we received reports of a decline of oak trees in the Ghorogh Region of the Golestan Forests. The decline began with discolorations and browning of the leaves, resulting in drying of the foliage. Viscous liquid exudates were observed on the trunks, resulting in a brown-black discoloration of phloem and bark. In January 2011, all infected trees were dead and exhibited symptoms of charcoal disease with carbonaceous, perithecial stromata erupting from the bark on stems. Perithecia were obovoid, containing short-stipitate, amyloid asci with dark brown, ellipsoid ascospores, 14 to 19 × 7 to 9 μm, with straight germ slits along the spore length. On the basis of these morphological characteristics, the fungus was identified as Biscogniauxia mediterranea. Blast searches of the NCBI GenBank nucleotide database were done using ITS sequences derived from three cultures (CBS 129072 to 129074). GenBank Accession Nos. JF295127 to JF295129 of the isolated fungus differed by one nucleotide from B. mediterranea (GenBank Accession No. AF280624) (1,3). Pathogenicity tests were conducted using an isolate of B. mediterranea under greenhouse conditions. Six-month-old Q. castaneifolia seedlings were inoculated by means of stem wounds with a mycelial plug of colonized potato dextrose agar. After 6 months, typical decline disease symptoms associated with charcoal disease were observed and the same fungus was reisolated. Perithecia were observed on the surface of black carbonaceous stromata, which usually developed on stems of inoculated plants. The decline is known as charcoal disease because fungal growth induces a typical charcoal-black surface on diseased branches and trunks. The pathogen can easily spread through large cavity vessels, colonize bark and woody tissues, and is able to kill the host in a single, growing season. B. mediterranea causes necrosis on stems and branches of Quercus spp., including Q. suber, Q. cerris, Q. frainetto, Q. pubescens (4), Q. alba, Q. ilex, Q. imbricaria, Q. lusitanica, Q. palustris, and Q. pyrenaica (2) in Europe, North America, Africa, New Zealand, and Asia (China and India). On the basis of our current knowledge, Q. castaneifolia represents a new host of B. mediterranea, and this is the first report of this fungal pathogen from Iran causing charcoal disease on Q. castaneifolia trees in the Golestan Forest. Given its new introduction into Iran, it is highly likely that it will spread to species of Fagus, Zelkova, and other woody hosts in the area. References: (1) J. Collado et al. Mycologia 93:875, 2001. (2) D. L. Hawksworth. No. 359. Description of Pathogenic Fungi and Bacteria. CMI, Kew, UK, 1972. (3) A. Mazzaglia et al. Mycol. Res. 105:952, 2001. (4) A. Vannini and G. Scarascia Mugnozza. Eur. J. For. Pathol. 21:193, 1991.


Author(s):  
Gabriella Vindigni ◽  
Alfredo Pulvirenti ◽  
Salvatore Alaimo ◽  
Clara Monaco ◽  
Daniela Spina ◽  
...  

Fisheries products are some of the most traded commodities world-wide and the potential for fraud is a serious concern. Fish fraud represents a threat to human health and poses serious concerns due to the consumption of toxins, highly allergenic species, contaminates or zoonotic parasites, which may be present in substituted fish. The substitution of more expensive fish by cheaper species, with similar morphological characteristics but different origins, reflects the need for greater transparency and traceability upon which which the security of the entire seafood value-chain depends. Even though EU regulations have made significant progress in consumer information by stringent labelling requirements, fraud is still widespread. Many molecular techniques such as DNA barcoding provide valuable support to enhance the Common Fisheries Policy (CFP) in the protection of consumer interests by unequivocally detecting any kind of fraud. This paper aims to highlight both the engagement of EU fishery policy and the opportunity offered by new biotechnology instruments to mitigate the growing fraud in the globalized fish market and to enforce the food security system to protect consumers’ health. In this paper, after a presentation of EU rules on fish labeling and a general overview on the current state of the global fish market, we discuss the public health implications and the opportunities offered by several techniques based on genetics, reporting a case study to show the efficacy of the DNA barcoding methodology in assessing fish traceability and identification, comparing different species of the Epinephelus genus, Mottled Grouper (Mycteroperca rubra) and Wreckfish (Polyprion americanus), often improperly sold with the commercial name of “grouper”.


Nematology ◽  
2021 ◽  
pp. 1-21
Author(s):  
Natsumi Kanzaki ◽  
Hayato Masuya ◽  
Keiko Hamaguchi

Summary Two new Neomisticius species, typologically and phylogenetically close to each other, are described and illustrated from dead Quercus trees and an ambrosia beetle, Platypus quercivorus. The two species share some stylet morphological characteristics, namely, they both possess a long conus occupying more than half of the total stylet length, a long crustaformeria composed of more than 160 cells (eight rows of more than 20 cells each), and a short and broad female tail with a digitate tip. They are distinguished from each other by N. variabilis n. sp. having a wide, spindle-shaped male bursa with a blunt terminus and N. platypi n. sp. having an oval bursa with a rounded terminus. In addition, the males and females of both species have three large rectal glands and the posterior end of the male testis (distal end of the vas deferens) bears three cells that seemingly function as a valve between the vas deferens and the cloacal tube. These characteristics have not been reported in other tylenchids. Currently, the genus contains only three species: the two new species and N. rhizomorphoides, which has a normal stylet with a short conus, a short crustaformeria, and lacks rectal glands and valve cells in the vas deferens. Therefore, the two new species are readily distinguished from N. rhizomorphoides and, based on the previous definition, may even represent a new genus. However, considering their phylogenetic closeness and biological similarities (e.g., association with ambrosia beetles), the generic definition of Neomisticius was emended to include these new species.


Diversity ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 580
Author(s):  
Hongyi Liu ◽  
Yufeng Zhang ◽  
Wei Xu ◽  
Yu Fang ◽  
Honghua Ruan

Identification based on conventional morphological characteristics is typically difficult and time-consuming. The development of molecular techniques provides a novel strategy that relies on specific mitochondrial gene fragments to conduct authentication. For this study, five newly sequenced partial mitogenomes of earthworms (Bimastos parvus, Dendrobaena octaedra, Eisenia andrei, Eisenia nordenskioldi, and Octolasion tyrtaeum) with lengths ranging from 14,977 to 15,715 were presented. Each mitogenome possessed a putative control region that resided between tRNA-Arg and tRNA-His. All of the PCGs were under negative selection according to the value of Ka/Ks. The phylogenetic trees supported the classification of Eisenia and Lumbricus; however, the trees based on cox1 did not. Through various comparisons, it was determined that cox1 fragments might be more suitable for molecular identification. These results lay the foundation for further phylogenetic studies on Lumbricidae.


2019 ◽  
Vol 72 ◽  
pp. 281
Author(s):  
Robert K. Taylor ◽  
Merje Toome-Heller ◽  
Wellcome W.H. Ho ◽  
Brett J.R. Alexander

The Mycology and Bacteriology team of the Ministry for Primary Industries’ Plant Health and Environment Laboratory is responsible for the identification and verification of all suspected exotic, new, and emerging pathogens affecting plants and the environment in New Zealand. We work in an applied diagnostic environment where results can have significant implications for biosecurity. Sample submissions often result in detection of new to New Zealand fungi and bacteria on plants for which information on fungal and bacterial associations is generally sparse. The complexity of testing required is quite varied with samples being submitted from post entry quarantine (looking for a known pathogen using specific tests), border or surveillance (unknown pathogens requiring multiple tests), or a biosecurity response (scaling up to test large numbers, identification resolution required to strain level). Applied test methods depend largely on the sample type and consist of morphological identification, biochemical testing, pathogenicity testing, serological and molecular techniques, including high throughput sequencing. A profile of our diagnostic work and the most commonly detected taxa and host associations are presented.


2010 ◽  
Vol 47 (2) ◽  
pp. 105-114 ◽  
Author(s):  
B. Koubková ◽  
V. Baruš ◽  
I. Hodová

AbstractThree nematode species of Cithariniella (Pharyngodonidae), C. citharini, C. khalili, and C. gonzalesi, were recorded from the recta of squeaker (Mochokidae: Siluriformes) and citharinid (Citharinidae: Characiformes) fishes from Senegal, West Africa. Morphological characteristics obtained by scanning electron microscopy (form of oral aperture and cephalic papillae, presence of lateral alae, distribution and form of cloacal papillae, simple or paired papillae on tail of males, eggs with numerous long filaments on each pole in females) correspond well to the generic diagnosis and represent species differences. The shape and size of the cephalic papillae and lips were identified as a new determination feature. C. gonzalesi is reported for the first time from Senegal and its host, Paradistichodus dimidiatus, represents a new host record. A tentative simple key for differentiating C. citharini, C. khalili, C. gonzalesi and C. petterae is provided based upon these results.


HortScience ◽  
2018 ◽  
Vol 53 (9) ◽  
pp. 1266-1270 ◽  
Author(s):  
Nader R. Abdelsalam ◽  
Hayssam M. Ali ◽  
Mohamed Z.M. Salem ◽  
Elsayed G. Ibrahem ◽  
Mohamed S. Elshikh

Mango (Mangifera indica L.) is a fruit crops belong to the family Anacardiaceae and is the oldest cultivated tree worldwide. Cultivars maintained in Egypt have not been investigated previously. Mango was first brought to Egypt from South Asia. Morphological and molecular techniques were used to identify the genetic diversity within 28 mango cultivars. SSR and EST-SSR were used for optimizing germplasm management of mango cultivars. Significant variations were observed in morphological characteristics and genetic polymorphism, as they ranged from 0.71% to 100%. High diversity was confirmed as a pattern of morphological and genotypes data. Data from the present study may be used to calculate the mango relationship and diversity currently grown in Egypt.


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