scholarly journals First Report of Armillaria Root Rot Caused by Armillaria mellea Infecting Carrizo Citrange and Sour Orange Rootstocks in Turkey

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1439-1439 ◽  
Author(s):  
F. Baysal-Gurel ◽  
A. Cinar
Keyword(s):  
Root Rot ◽  
Root Systems ◽  
Causal Agent ◽  
Poncirus Trifoliata ◽  
Sour Orange ◽  
Potato Dextrose Broth ◽  
First Report ◽  
Armillaria Mellea ◽  
Carrizo Citrange ◽  
Armillaria Root Rot

Citrus rootstocks, Carrizo citrange (Citrus sinensis [L.] Osb. × Poncirus trifoliata [L.] Raf.) and sour orange (C. aurantium L.) grown in containers filled with 5 liters of potting mix of 40% peat and 60% volcanic tuff declined in a 0.2-ha commercial nursery in Adana, Turkey, between 2004 and 2007. Seedlings with symptoms of root rot were found with an average disease incidence of 20% among 1,000 Carrizo citrange seedlings and 10% among 15,000 sour orange seedlings. The potting mixture preparation unit was located next to an oak tree (Quercus sp.) showing symptoms of Armillaria root rot. Six- to 12-month-old seedlings of both rootstocks were stunted and the crowns were necrotic with the presence of white mycelium. Mycelial fans were observed beneath the bark of infected roots and they expanded into the crown. The root systems and nearby potting mix contained rhizomorphs. Thus, Armillaria spp. was suspected as a possible causal agent. Three diseased crowns and three rhizomorphs were surface-sterilized with 1% NaClO for 1 min and cultured on benomyl-dichloran-streptomycin containing selective medium (3) at 25°C in the dark for 1 week. Six isolates transferred to 1.5% malt extract agar at 33°C in the dark for 7 weeks consistently yielded abundant aerial hyphae and mean diameter growth range was 4 to 21 mm and the mycelium margin was regular (1). To confirm pathogen identity, total DNA was extracted using the PowerSoil DNA Isolation Kit (MO BIO Laboratories, Inc., CA) directly from 7-day-old cultures grown in potato dextrose broth (PDB). The ribosomal DNA internal transcribed spacer (ITS) region was amplified by PCR using the primer pair ITS1 and ITS4 (5) and sequenced. The sequences were 99% identical to that of Armillaria mellea isolates from Japan (AB510880) and China (KF032535). This confirmed the identity of the causal agent as A. mellea (Vahl.) P. Kumm. Ten 3-month-old seedlings of Carrizo citrange and sour orange were transplanted into steam-sterilized potting mix and inoculated with wood pieces of oak (Quercus sp.) colonized by the fungus (two pieces for each container) (2). The oak wood pieces were sterilized prior to the colonization by the pathogen. Plants were maintained in a greenhouse (23 to 25°C) until symptoms appeared. Ten non-inoculated seedlings from each rootstock served as controls and were maintained in the same environment. After 4 months, the crowns of the seedlings developed necrotic areas and root systems contained rhizomorphs on all inoculated seedlings and fungus was re-isolated from crowns and rhizomorphs. All control plants remained disease-free and no fungus was re-isolated. A. mellea was reported to infect citrus rootstocks in Spain in 1999 (4). To our knowledge, this is the first report of Armillaria root rot caused by A. mellea infecting Carrizo citrange and sour orange rootstocks in Turkey. This indicates that citrus rootstocks could be at risk for infection and sterilization of the potting mix and good sanitation practices in nurseries are very important. References: (1) J. N. Bruhn et al. Mycopathologia 142:89, 1998. (2) F. M. Grasso et al. Plant Dis. 91:1517, 2007. (3) T. C. Harrington et al. Page 81 in: Methods for Research on Soilborne Phytopathogenic Fungi. APS Press, St. Paul, MN, 1992. (4) J. J. Tuset et al. Bol. San. Veg. Plagas 25: 491, 1999. (5) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

Identification of the causal agent of Armillaria root rot of Pinus species in South Africa

Mycologia ◽  
2000 ◽  
Vol 92 (4) ◽  
pp. 777-785 ◽  
Author(s):  
Martin P. A. Coetzee ◽  
Brenda D. Wingfield ◽  
Teresa A. Coutinho ◽  
Michael J. Wingfield
Keyword(s):  
South Africa ◽  
Root Rot ◽  
Causal Agent ◽  
Pinus Species ◽  
Armillaria Root Rot

scholarly journals Performance of ‘Valencia’ Sweet Orange Trees on 12 Rootstocks at Two Locations and an Economic Interpretation as a Basis for Rootstock Selection

HortScience ◽  
2010 ◽  
Vol 45 (4) ◽  
pp. 523-533 ◽  
Author(s):  
William S. Castle ◽  
James C. Baldwin ◽  
Ronald P. Muraro ◽  
Ramon Littell
Keyword(s):  
Financial Analysis ◽  
Sweet Orange ◽  
Poncirus Trifoliata ◽  
Soluble Solids ◽  
Juice Quality ◽  
Sour Orange ◽  
Central Florida ◽  
Carrizo Citrange ◽  
Acid Ratio ◽  
Fruit Samples

Two field experiments with ‘Valencia’ sweet orange [Citrus sinensis (L.) Osb.] trees propagated on 12 rootstocks were conducted in commercial orchards. The objectives were to compare rootstock horticultural performance between two locations with soils representative of the Central Florida Ridge (AP) and coastal flatwoods (I), the major citrus-growing regions in Florida, and to see if financial analysis would provide an improved basis for interpreting rootstock performance. The randomized complete-block trials involved six-tree plots replicated eight or 10 times at planting densities of 358 trees (AP) or 252 trees (I)/ha, respectively. Tree growth and survival, yield, and juice quality were measured for 15 years. When losses occurred, trees were replaced annually with another one on the same rootstock. The data of seven rootstocks were subjected to a financial interpretation of three scenarios: tree loss and tree loss with or without tree replacement using the discounted cash flow and internal rate of return methods at a 15% rate. At the flatwoods location, when differences among replications became apparent on several rootstocks, soil data were collected to study its possible association to tree performance; also in this trial, 400-kg fruit samples were differentially harvested in 2 successive years from mature trees on each of five commercial rootstocks when the juice soluble solids/acid ratio was near 15. The juice was extracted, pasteurized, and evaluated for flavor by an experienced taste panel. The horticultural data obtained for trees on specific well-studied rootstocks [Volkamer (C. volkameriana Ten. & Pasq.)] and rough (C. jambhiri Lush.) lemons, Carrizo citrange [C. sinensis × Poncirus trifoliata (L.)], sour orange [C. aurantium (L.)], Cleopatra mandarin (C. reshni Hort. ex Tan.), trifoliate orange (P. trifoliata), a selection of sweet orange (C. sinensis), and Swingle citrumelo (C. paradisi Macf. × P. trifoliata) at both locations were typical of their well-documented performance in Florida and elsewhere. Tree losses were virtually only from citrus blight and ranged from none (sour orange) to greater than 50% (Volkamer and rough lemons) at both locations, although tree loss began later at the Central Florida location. ‘Valencia’ cuttings (only at the flatwoods site) were long-lived and cropped well for their smaller size compared with the budded trees. Taste panelists were not able to distinguish differences over two seasons among pasteurized ‘Valencia’ juices produced from trees on different rootstocks and normalized by soluble solids/acid ratio. Yield and planting density were the main factors affecting financial outcome; also, in the highly variable soils of the coastal flatwoods, trees growing in sites with greater depth to an argillic layer had 30% to 200% higher yields. Trees on Volkamer lemon had only ≈50% survival at both locations but had the highest ($7,338/ha I) or one of the highest cash flows ($13,464/ha AP) as compared with one of the commercial standards, Carrizo citrange ($6,928 I; $16,826 AP), which had only ≈25% tree loss. Inclusion of financial analysis, with certain limitations, was concluded to considerably improve rootstock selection decisions compared with selection based only on horticultural data.

scholarly journals Soybean Sudden Death Syndrome Causal Agent Fusarium brasiliense Present in Michigan

Plant Disease ◽  
2019 ◽  
Vol 103 (6) ◽  
pp. 1234-1243 ◽  
Author(s):  
Jie Wang ◽  
Hyunkyu Sang ◽  
Janette L. Jacobs ◽  
Kjersten A. Oudman ◽  
Linda E. Hanson ◽  
...  
Keyword(s):  
Sudden Death ◽  
Rna Polymerase Ii ◽  
Root Rot ◽  
The United States ◽  
Causal Agent ◽  
Sudden Death Syndrome ◽  
Nuclear Ribosomal Dna ◽  
First Report ◽  
Fusarium Sp ◽  
Pathogenicity Assay

Sudden death syndrome (SDS), caused by members of Fusarium solani species complex (FSSC) clade 2, is a major and economically important disease in soybean worldwide. The primary causal agent of SDS isolated to date in North America has been F. virguliforme. In 2014 and 2016, SDS symptoms were found in two soybean fields located on the same farm in Michigan. Seventy Fusarium strains were isolated from roots of the SDS-symptomatic soybeans in two fields. Phylogenetic analysis of partial sequences of elongation factor-1α, the nuclear ribosomal DNA intergenic spacer region, and the RNA polymerase II beta subunit revealed that the primary FSSC species isolated was F. brasiliense (58 and 36% in each field) and the remaining Fusarium strains were identified as F. cuneirostrum, F. phaseoli, an undescribed Fusarium sp. from FSSC clade 2, and strains in FSSC clade 5 and FSSC clade 11. Molecular identification was supported with morphological analysis and a pathogenicity assay. The soybean seedling pathogenicity assay indicated that F. brasiliense was capable of causing typical foliar SDS symptoms. Both root rot and foliar disease severity were variable by strain, just as they are in F. virguliforme. Both FSSC 5 and FSSC 11 strains were also capable of causing root rot, but SDS foliar symptoms were not detected. To our knowledge, this is the first report of F. brasiliense causing SDS in soybean in the United States and the first report of F. cuneirostrum, F. phaseoli, an as-yet-unnamed Fusarium sp., and strains in FSSC clade 5 and FSSC clade 11 associated with or causing root rot of soybean in Michigan.

scholarly journals MORTALITY CAUSED BY ARMILLARIA ROOT ROT, PERIDERMIUM RUSTS AND OTHER DESTRUCTIVE AGENTS IN LODGEPOLE PINE REGENERATION

1964 ◽  
Vol 40 (3) ◽  
pp. 350-361 ◽  
Author(s):  
J. A. Baranyay ◽  
G. R. Stevenson
Keyword(s):  
Mortality Rate ◽  
High Mortality ◽  
Root Rot ◽  
Lodgepole Pine ◽  
Armillaria Mellea ◽  
Large Numbers ◽  
Armillaria Root Rot ◽  
Pine Regeneration

Surveys of diseases and other forms of damage in naturally regenerated lodgepole pine were carried out in 1959 and 1962 near Robb, Alberta in an area that had been burned in May, 1941. Eighteen and one-half per cent of the trees on seven 0.05-acre plots were dead in 1959. The additional mortality on the same plots from 1959 to 1962 was 27.7 per cent. The seemingly high mortality was not considered excessive, in light of the large numbers of trees remaining on the plots, but further examinations will show if the present high mortality rate is sustained. The most important destructive agent up to 1962 was Armillaria mellea (Vahl ex Fr.) Quél. The most important non-infectious destructive agents were game and rodents.

Armillaria root rot in Wisconsin aspen sucker stands

1987 ◽  
Vol 17 (9) ◽  
pp. 995-1000 ◽  
Author(s):  
G. R. Stanosz ◽  
R. F. Patton
Keyword(s):  
Root Rot ◽  
Mycelial Growth ◽  
Root Systems ◽  
Stand Age ◽  
Clear Cutting ◽  
Infected Tree ◽  
Armillaria Root Rot ◽  
Infected Root

Roots of 50 healthy-appearing dominant or codominant aspen suckers were examined for signs of Armillaria root rot in each of nine stands (three each 3, 9, or 15 years after clear-cutting). Lesion numbers, sizes, and positions were also recorded for two of these stands of each age. Infection had occurred by rhizomorph penetration, mycelial growth through roots from parent stumps, and by contact with colonized roots and was only infrequently associated with obvious injuries. Rot incidence increased as a function of stand age, with > 70% of sampled trees affected in 15-year-old stands. More lesions per infected tree and shorter distances from stems to nearest lesions also occurred in the 15-year-old stands. There colonization extended to stem bases in > 25% of infected root systems and to within 10 cm of stem bases in > 50%. Results indicate the potential for losses caused by Armillaria root rot in aspen sucker stands as they continue to develop and approach harvest age.

Identification of the Causal Agent of Armillaria Root Rot of Pinus Species in South Africa

Mycologia ◽  
2000 ◽  
Vol 92 (4) ◽  
pp. 777 ◽  
Author(s):  
Martin P. A. Coetzee ◽  
Brenda D. Wingfield ◽  
Teresa A. Coutinho ◽  
Michael J. Wingfield
Keyword(s):  
South Africa ◽  
Root Rot ◽  
Causal Agent ◽  
Pinus Species ◽  
Armillaria Root Rot

scholarly journals First Report of Citrus Blight in Costa Rica

Plant Disease ◽  
2005 ◽  
Vol 89 (1) ◽  
pp. 108-108
Author(s):  
W. Villalobos ◽  
L. Moreira ◽  
K. S. Derrick ◽  
M. J. G. Beretta ◽  
C. Rivera
Keyword(s):  
Costa Rica ◽  
Water Uptake ◽  
Average Concentration ◽  
Causal Agent ◽  
Tree Canopy ◽  
Poncirus Trifoliata ◽  
Poor Growth ◽  
First Report ◽  
General Decline ◽  
Citrus Blight

Citrus blight (CB), causing a chronic decline of citrus, has been an important disease in Florida for over 100 years. CB was first reported in Brazil in the 1980s and is now responsible for the removal of nearly 10% of the trees from production annually. No causal agent has been identified, but CB has been root-graft transmitted to healthy trees, suggesting that the causal agent is infectious (3). Since 1997, CB symptoms were observed in several groves in northern Costa Rica, the most important citrus area of approximately 25,000 ha. Symptoms observed include a general decline and wilt of the tree canopy, off-color leaves, leaf drop, twig dieback, small fruit, delayed blossom, poor growth, and death. A survey near Guanacaste revealed CB symptoms in 7-yr-old Valencia and Pineapple orange trees (Citrus sinensis (L.) Osbeck) grafted on Carrizo citrange (C. sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf.) rootstock. Since 1997, 6% of the trees in this area have been replanted annually because of CB symptoms. Similar situations were observed in other groves in the northern citrus area. Dot immunobinding assays (DIBA) (1) were used to detect the P12 protein associated with CB with 20 of 22 trees showing CB-like symptoms giving a positive test. Zinc (Zn) accumulation in trunk wood and water uptake tests were done according to Roistacher (2) in 8 healthy and 20 symptomatic trees which were positive for CB using DIBA. The average Zn concentration of 16 declining trees was 4.6 ± 1.9, whereas the average concentration for 8 healthy trees was 2.0 ± 0.9. The average water uptake in 1 min was 14 ml for healthy trees, and virtually zero for the 20 symptomatic trees. These diagnostic tests confirm the presence of CB in the northern citrus area of Costa Rica, and the surveys indicate the disease is beginning to spread and become economically important. To our knowledge, this is the first report of CB in commercial citrus in Costa Rica. References: (1) K. S. Derrick et al. Plant Dis. 74:168, 1990. (2) C. N. Roistacher. Pages 57–66 in: Graft-Transmissible Diseases of Citrus. Handbook for Detection and Diagnosis. C.N. Roistacher, ed. Food and Agriculture Organization, Rome, 1991. (3) D. P. H. Tucker et al. Plant Dis. 68:979, 1984.

scholarly journals First Report of Pythium spinosum as a Causal Agent of Crown and Root Rot in Greenhouse Cucumber Cultivation in Italy

Plant Disease ◽  
2020 ◽  
Vol 104 (12) ◽  
pp. 3269
Author(s):  
L. Sigillo ◽  
C. Pane ◽  
I. Garaguso ◽  
L. Luongo ◽  
M. Galli ◽  
...  
Keyword(s):  
Root Rot ◽  
Causal Agent ◽  
First Report ◽  
Greenhouse Cucumber ◽  
Crown And Root Rot

scholarly journals First Report of Cylindrocarpon macrodidymum on Acer palmatum in Virginia

Plant Disease ◽  
2011 ◽  
Vol 95 (12) ◽  
pp. 1592-1592 ◽  
Author(s):  
N. L. Dart ◽  
S. M. Weeda
Keyword(s):  
Root Rot ◽  
Root Systems ◽  
Specific Primers ◽  
First Report ◽  
Root Stock ◽  
Species Specific ◽  
Stem Cankers ◽  
Lower Stem ◽  
Tree View ◽  
Unknown Isolate

In October 2010, containerized Acer palmatum Thunb. trees (‘Red Select’, ‘Viridis’, and ‘Hubb's Red Willow’) with crown cankers and root rot were observed at a central Virginia nursery. Sections of lower stem cankers and rootlets were sampled from 14 trees by surface-sterilizing tissue and plating on V8 juice agar. A species of Cylindrocarpon was isolated from 72% of sampled trees and recovered from 57% of 50 cankers and 74% of 50 sections of symptomatic rootlets. On potato dextrose agar (PDA), macroconidia were cylindrical, straight, and rounded at both ends. Chlamydospores were common and intercalary or terminal in the mycelium. To identify to species, the internal transcribed spacer of ribosomal DNA and partial sequences of the beta tubulin gene were sequenced and compared with published sequences (GenBank Accession Nos. AM419110.1 and AM419109.1), which exactly matched sequences of Cylindrocarpon macrodidymum, a recently described species (1,2). Neighbor-joining analyses using Blast Tree View placed C. macrodidymum and the unknown isolate in a closely related but distinct clade from C. pauciseptatum and C. liriodendri. Species-specific primers also confirmed the isolates to be C. macrodidymum (2). A. palmatum seedlings (generic root stock) were inoculated by placing a colonized PDA plug over 1-cm scalpel incision wounds (n = 12) and wrapping treated sections of stem with Parafilm to prevent desiccation. Twelve root systems were inoculated by mixing a colonized PDA plate with 1 liter of water and drenching the soil of each plant. Twelve wounds and root systems were inoculated with uncolonized PDA for controls. After 4 weeks, inoculated wounded seedlings developed brown lesions extending 1 to 3 cm from incision wounds. Inoculated roots developed root rot. Controls produced no visible symptoms. A Cylindrocarpon sp. was recovered from 85% of surface-sterilized sections of inoculated wounded stem and 100% inoculated symptomatic roots. No Cylindrocarpon sp. was isolated from stem or root controls. To our knowledge, this is the first report of this pathogen on A. palmatum. Other reported hosts include grapevines (Vitis spp.) and apple (Malus spp.) (3). This finding demonstrates the ability of C. macrodidymum to impact an ornamental host and the potential for this pathogen to impact the ornamental nursery industry. References: (1) S. Alaniz et al. Plant Dis. 93:821, 2009. (2) J. Auger et al. Plant Dis. 91:470, 2007. (3) Y. T. Tewoldemedhin et al. Eur. J. Plant Pathol. 129:637, 2011.

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