Bacterial canker of stone-fruit trees in California

Hilgardia ◽  
1933 ◽  
Vol 8 (3) ◽  
pp. 83-123 ◽  
Author(s):  
Edward E. Wilson
Plant Disease ◽  
2020 ◽  
Vol 104 (3) ◽  
pp. 882-892 ◽  
Author(s):  
Khumbuzile N. Bophela ◽  
Yolanda Petersen ◽  
Carolee. T. Bull ◽  
Teresa. A. Coutinho

Bacterial canker is a common bacterial disease of stone fruit trees. The causal agents responsible for the disease include several pathovars in Pseudomonas syringae sensu lato and newly described Pseudomonas species. Pseudomonad strains were isolated from symptomatic stone fruit trees, namely apricot, peach, and plum trees cultivated in spatially separated orchards in the Western Cape. A polyphasic approach was used to identify and characterize these strains. Using a multilocus sequence typing approach of four housekeeping loci, namely cts, gapA, gyrB, and rpoD, the pseudomonad strains were delineated into two phylogenetic groups within P. syringae sensu lato: P. syringae sensu stricto and Pseudomonas viridiflava. These results were further supported by LOPAT diagnostic assays and analysis of clades in the rep-PCR dendrogram. The pseudomonad strains were pathogenic on both apricot and plum seedlings, indicative of a lack of host specificity between Pseudomonas strains infecting Prunus spp. This is a first report of P. viridiflava isolated from plum trees showing symptoms of bacterial canker. P. viridiflava is considered to be an opportunistic pathogen that causes foliar diseases of vegetable crops, fruit trees, and aromatic herbs, and thus the isolation of pathogenic P. viridiflava from twigs of plum trees showing symptoms of bacterial canker suggests that this bacterial species is a potentially emerging stem canker pathogen of stone fruit trees in South Africa.


Author(s):  
V. P. Hayova

Abstract A description is provided for Leucostoma cinctum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Leucostoma cinctum, especially in its conidial state, is a well-known pathogen of stone-fruit trees causing necrosis of twigs, perennial Cytospora-canker. The fungus penetrates mainly through the scars, and may result in dieback of branches or even whole trees. Tree susceptibility to L. cinctum is influenced by lesions (Stanova, 1990). Comparative anatomy and host response of peach cultivars inoculated with L. cinctum was studied by Biggs (1986). Resistance of different cultivars of stone-fruit trees to L cinctum has been investigated by many authors (Cociu et al., 1991; Miles et al., 1989; Pedryc & Rozsnyai, 1991). HOSTS: On dead or dying, attached or fallen twigs of the Rosaceae, mainly Prunoideae (Amygdalus, Armeniaca, Cerasus, Persica, Prunus) and rarely other subfamilies of the Rosaceae, including genera such as Cotoneaster, Crataegus, Malus and Pyrus. GEOGRAPHICAL DISTRIBUTION: Asia: Armenia, Republic of Georgia, Iran, Kazakhstan, Russia, Turkmenistan, Uzbekistan. Australasia: Australia. Europe: Czech Republic, France, Germany, Hungary, Italy, Moldova, Rumania, Russia, Slovakia, Spain, Switzerland, Sweden, Turkey, UK, Ukraine, former Yugoslavia. North America: Canada, USA (Idaho, Michigan, New-Jersey, Oregon). TRANSMISSION: Both conidia and ascospores are air-borne, especially under humid conditions. Orange or reddish droplets or tendrils of conidia extruded from conidiomata can be often seen after rain. It is also known that arthropods can carry propagules in stone-fruit orchards (Helton et al., 1988).


Plant Disease ◽  
2002 ◽  
Vol 86 (5) ◽  
pp. 543-546 ◽  
Author(s):  
R. J. Sayler ◽  
S. M. Southwick ◽  
J. T. Yeager ◽  
K. Glozer ◽  
E. L. Little ◽  
...  

Bacterial canker is one of the most economically important diseases of stone fruit trees, including ‘French’ prune (Prunus domestica). Field trials were conducted to evaluate the effect of rootstock selection and budding height on the incidence and severity of bacterial canker in four orchards with low to high disease pressure. Treatments included French prune scions low-grafted on ‘Lovell’ peach (Prunus persica) rootstocks as well as Myrobalan 29C (Prunus cerasifera) plum rootstocks grafted at 15, 50, and 90 cm above the rootstock crown. Another treatment consisted of growing Myrobalan 29C plum rootstocks in the field for one growing season, then field-grafting French prune buds onto rootstock scaffolds. Lovell peach rootstock provided the greatest protection from bacterial canker as measured by disease incidence and tree mortality in all orchards. Field-budded rootstocks and rootstocks grafted at the highest budding height provided moderate levels of resistance to bacterial canker. These treatments reduced the incidence but not the severity of disease.


Plant Disease ◽  
2020 ◽  
Author(s):  
Rachid Tahzima ◽  
Radouane Qessaoui ◽  
Yoika Foucart ◽  
Sebastian Massart ◽  
Kris De Jonghe

Plum (Prunus domestica L., Rosaceae) trees, like many stone fruit trees, are known to be infected by numerous plant viruses, predominantly as consequence of their clonal mode of propagation and perennial cultivation (Jelkmann and Eastwell, 2011). Apricot vein clearing-associated virus (AVCaV) is a member of the genus Prunevirus in the family Betaflexiviridae. AVCaV was first reported in Italy infecting apricot (P. armeniaca L.) associated with foliar vein clearing symptoms (Elbeaino et al. 2014). It has also been detected in various Prunus species, like plum, Japanese plum (P. salicina L.), sour cherry (P. cerasus L.), and Japanese apricot (P. mume L.), apricot and peach (P. persica L.) sourced from Asian and European countries (Marais et al. 2015), as well as in the ornamental Myrobolan plum (P. cerasifera L.) in Australia (Kinoti et al. 2017). In 2018, during the vegetative season, a survey was carried out in two different apricot and plum orchards in the southern region of Agdez (Agadir, Morocco) where stone fruit trees are grown. Five branches with leaves were sampled from three apricot and three plum trees of unknown cultivars, all asymptomatic. Total RNA was extracted from 100 mg plant tissue (leaves and cambial scrapping) using RNeasy Plant Mini Kit (QIAGEN, Hilden, Germany) and separate samples (one per species) were used for library preparation (NEBNext Ultra RNA library kit; New England BioLabs, MA, USA), and sequencing (Illumina NextSeq v2, totRNA sequencing) at Admera Health (New Jersey, USA). All generated reads (6,756,881) from the plum sample were quality filtered and submitted to the VirusDetect pipeline (Zheng et al., 2017). The plum cDNA library, a total of 20 viral contigs (68-1928 bp) mapped to several AVCaV accessions in GenBank. A reference mapping (CLC Genomics Workbench 12, Qiagen, Denmark) was conducted against all four available AVCaV full genomes (KM507062-63, KY132099 and HG008921), revealing 100% coverage of the full sequence (8358 nt) with 97-98 % nucleotide (nt) identities (BLASTn). Analysis of the derived sequences allowed to identify the location of the four predicted ORFs i.e. (ORF1: 6066 nt/2,021 aa), (ORF2: 1383 nt/460 aa), (ORF3: 666 nt/221 aa) and (ORF4: 420 nt/139 aa), previously described for the AVCaV genome (Elbeaino et al. 2014). The amino acid sequences of the encoded proteins of AVCaV isolate from Morocco also shared 97-98% identities with the corresponding sequences of complete genome AVCaV isolates in GenBank. To confirm the detection of AVCaV in the three plum samples, specific RT-PCR primers (VC37657s: 5’-CCATAGCCACCCTTTTTCAA-3’ / VC28239a: 5’-GTCGTCAAGGGTCCAGTGAT-3’) (Elbeaino et al. 2014) were used and the expected 330 bp fragment from the replicase gene was amplified in all three samples and subsequently sequenced (MT980794-96). Sanger sequences were 100% identical to corresponding HTS derived sequence. This is the first report of AVCaV infecting plum in Africa. The incidence of AVCaV in Moroccan Prunus species is unknown. Plum trees from the surveyed orchards were also confirmed to be co-infected with little cherry virus 1 (LChV-1) using HTS. Further investigation is required to determine the impact of AVCaV on these asymptomatic plum trees and other stone fruits species.


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