scholarly journals Management of pathogens in seed orchards and nurseries

1991 ◽  
Vol 67 (5) ◽  
pp. 481-485 ◽  
Author(s):  
Jack R. Sutherland
Keyword(s):  
Root Rot ◽  
Seed Orchard ◽  
Forest Nursery ◽  
Damping Off ◽  
Seed Orchards ◽  
Root Rots ◽  
Armillaria Root Rot ◽  
Cylindrocladium Floridanum ◽  
Gray Mould ◽  
And Storage

The biology, damage and impact, and recent innovations in management of the major diseases affecting seed orchard trees and cones and forest nursery seedlings across Canada are discussed. Specific diseases covered are Armillaria root rot (A. ostoyae) and inland spruce cone rust (Chrysomyxa pirolata) in seed orchards, and damping-off and root rots, especially Cylindrocladium floridanum, and gray (Botrytis cinerea) and storage moulds of forest nursery seedlings. Areas needing research are also mentioned. Key words: Root rots, cone rust, damping-off, gray mould, storage moulds

scholarly journals First Report of Phytophthora megasperma and Pythium irregulare As Olive Tree Root Pathogens

Plant Disease ◽  
1997 ◽  
Vol 81 (10) ◽  
pp. 1216-1216 ◽  
Author(s):  
M. E. Sánchez-Hernández ◽  
A. Ruiz-Dávila ◽  
A. Trapero-Casas
Keyword(s):  
Root Rot ◽  
Olive Tree ◽  
The United States ◽  
Damping Off ◽  
Phytophthora Megasperma ◽  
Root Rots ◽  
Foliar Symptoms ◽  
Root Pathogens ◽  
Root Necrosis ◽  
Olive Trees

Several species of the genus Phytophthora are associated with root rot and trunk cankers in olive trees (Olea europaea L.). Among them, Phytophthora megasperma has been cited as being associated with olive root rots in Greece (1). Unidentified species of Pythium and Phytophthora have also been associated with olive tree root rots in the United States. However, the status of P. megasperma and Pythium spp. as olive tree root pathogens has remained unclear. Following a 5-year period of severe drought in southern Spain, autumn-winter rainfall rates in 1996 to 1997 steadily increased in both quantity and frequency. Under these unusually wet conditions, olive trees remained waterlogged for several months. During this period, we observed foliar wilting, dieback, and death of young trees, and later found extensive root necrosis. In 46 of 49 affected plantations surveyed, P. megasperma was consistently isolated from the rotted rootlets, particularly in young (<1- to 10-year-old trees) plantations. This fungus was not detected on plant material affected by damping-off from several Spanish olive tree nurseries. The opposite situation occurred with P. irregulare. This species was not associated with rotted rootlets in the field. In contrast, it was consistently isolated from necrotic rootlets from young olive plants affected by damping-off. These plants were grown in a sand-lime-peat soil mixture under greenhouse conditions and showed foliar wilting and extensive necrosis of the root systems. Pathogenicity tests were conducted with several isolates of P. megasperma and P. irregulare on 6-month-old rooted cuttings of olive, under both weekly watering and waterlogged conditions. Under waterlogged conditions, both fungal species produced extensive root necrosis 2 weeks after inoculation that resulted in wilting of the aerial parts and rapid plant death. Waterlogged control plants remained without foliar symptoms but a low degree of root necrosis was recorded. In addition, under weekly watering conditions, plants inoculated with either species showed some degree of root rot but foliar symptoms were not evident. No differences in pathogenicity were observed within the Phytophthora or Pythium isolates. Reference: (1) H. Kouyeas and A. Chitzanidis. Ann. Inst. Phytopathol. Benaki 8:175, 1968.

Identification of metalaxyl and ethaboxam insensitive Pythium sylvaticum pathogenic to pulse crops in Montana, USA.

2021 ◽  
Author(s):  
Lipi Parikh ◽  
Swarnalatha Moparthi ◽  
Frankie Crutcher ◽  
Mary Burrows
Keyword(s):  
Root Rot ◽  
Damping Off ◽  
Management Options ◽  
Fungicide Sensitivity ◽  
Root Rots ◽  
Pulse Crops ◽  
Pythium Root Rot ◽  
Pythium Sylvaticum ◽  
Potential Pathogenicity

Pythium root rot and damping-off caused by Pythium spp. are important diseases of pulse crops. In a 2016 pathogen survey from dry pea growing fields in Montana, along with commonly known causal agents P. ultimum and P. irregulare, an isolate identified as P. sylvaticum (LPPY17) was isolated from the rhizosphere of a diseased pea plant collected from Valley County, MT. Root rots and damping-off caused by P. sylvaticum have not previously been reported for chickpea, pea, and lentil crops. The isolate LPPY17 was tested for fungicide resistance in vitro, and results indicated a reduced sensitivity to metalaxyl and ethaboxam containing fungicides. LPPY17 was also tested for pathogenicity on chickpea, pea, and lentil seedlings in the greenhouse, and the results from the study revealed LPPY17 is capable of causing both root rots and damping off. Due to the potential pathogenicity and reduced fungicide sensitivity of this species, in the future it will be important to monitor for P. sylvaticum in pulse root rot surveys and diagnostics, as management options may be different from other common Pythium spp.

scholarly journals Ecology and control of grapevine root diseases in New Zealand a review

2015 ◽  
Vol 68 ◽  
pp. 396-404
Author(s):  
D.C. Mundy
Keyword(s):  
New Zealand ◽  
Root Rot ◽  
Economic Loss ◽  
Foot Rot ◽  
Phytophthora Root Rot ◽  
Root Rots ◽  
Root Diseases ◽  
Armillaria Root Rot ◽  
Verticillium Dahlia ◽  
Black Foot

Grapevine root diseases can result in economic loss during vineyard establishment Symptoms may not be noticed in vineyards until vines die The death of young vines as a result of root rots can be a point of contention between the grower and the nursery supplying the plants In New Zealand root diseases include black foot rot (caused by Cylindrocarpon spp) verticillium wilt (caused by Verticillium dahlia) phytophthora root rot (caused by various Phytophthora spp) and armillaria root rot (caused in New Zealand by Armillaria novaezelandiae and A limonea) Of these diseases black foot rot is the most commonly observed in the field in New Zealand and has received the most study This review provides information on symptoms causal organisms disease cycles and where available control of grapevine root rots under New Zealand conditions

Phytophthora palmivora. [Descriptions of Fungi and Bacteria].

1985 ◽  
Author(s):  
D. J. Stamps
Keyword(s):  
Geographical Distribution ◽  
Root Rot ◽  
Phytophthora Palmivora ◽  
Infested Soil ◽  
Damping Off ◽  
Black Stripe ◽  
Root Rots ◽  
Wide Range ◽  
Black Pod ◽  
Rain Splash

Abstract A description is provided for Phytophthora palmivora. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: A wide range; 138 species of economic, ornamental, shade and hedge plants were listed (48, 337-344). DISEASE: Black pod and canker of cacao; patch canker, black stripe and leaf fall of Hevea rubber; bud rot of coconut and other palms; fruit and stem rot of pawpaw; root rots and damping-off of seedlings. GEOGRAPHICAL DISTRIBUTION: World-wide in tropical and warm temperature regions with high rainfall. TRANSMISSION: In cacao by direct contact between diseased and healthy pods, by rain splash from diseased pods, leaves and infested soil, and by insect vectors and ant tents. In rubber by rain. Soil as a source of inoculum for pawpaw root rot.

scholarly journals Bacillus megaterium-Mediated Synthesis of Selenium Nanoparticles and Their Antifungal Activity against Rhizoctonia solani in Faba Bean Plants

2021 ◽  
Vol 7 (3) ◽  
pp. 195
Author(s):  
Amr H. Hashem ◽  
Amer M. Abdelaziz ◽  
Ahmed A. Askar ◽  
Hossam M. Fouda ◽  
Ahmed M. A. Khalil ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Vicia Faba ◽  
Root Rot ◽  
Antifungal Agents ◽  
Damping Off ◽  
Growth Promoters ◽  
Root Rot Disease ◽  
Rot Disease

Rhizoctonia root-rot disease causes severe economic losses in a wide range of crops, including Vicia faba worldwide. Currently, biosynthesized nanoparticles have become super-growth promoters as well as antifungal agents. In this study, biosynthesized selenium nanoparticles (Se-NPs) have been examined as growth promoters as well as antifungal agents against Rhizoctonia solani RCMB 031001 in vitro and in vivo. Se-NPs were synthesized biologically by Bacillus megaterium ATCC 55000 and characterized by using UV-Vis spectroscopy, XRD, dynamic light scattering (DLS), and transmission electron microscopy (TEM) imaging. TEM and DLS images showed that Se-NPs are mono-dispersed spheres with a mean diameter of 41.2 nm. Se-NPs improved healthy Vicia faba cv. Giza 716 seed germination, morphological, metabolic indicators, and yield. Furthermore, Se-NPs exhibited influential antifungal activity against R. solani in vitro as well as in vivo. Results revealed that minimum inhibition and minimum fungicidal concentrations of Se-NPs were 0.0625 and 1 mM, respectively. Moreover, Se-NPs were able to decrease the pre-and post-emergence of R. solani damping-off and minimize the severity of root rot disease. The most effective treatment method is found when soaking and spraying were used with each other followed by spraying and then soaking individually. Likewise, Se-NPs improve morphological and metabolic indicators and yield significantly compared with infected control. In conclusion, biosynthesized Se-NPs by B. megaterium ATCC 55000 are a promising and effective agent against R. solani damping-off and root rot diseases in Vicia faba as well as plant growth inducer.

scholarly journals Pathogenicity and Virulence of Pythium Species Obtained from Forest Nursery Soils on Douglas-Fir Seedlings

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 744-748 ◽  
Author(s):  
Jerry E. Weiland ◽  
Bryan R. Beck ◽  
Anne Davis
Keyword(s):  
Pseudotsuga Menziesii ◽  
Seedling Survival ◽  
The United States ◽  
Douglas Fir ◽  
Tree Seedlings ◽  
Pythium Species ◽  
Forest Nursery ◽  
Damping Off ◽  
Greenhouse Study ◽  
Forest Nurseries

Pythium species are common soilborne oomycetes that occur in forest nursery soils throughout the United States. Numerous species have been described from nursery soils. However, with the exception of P. aphanidermatum, P. irregulare, P. sylvaticum, and P. ultimum, little is known about the potential for other Pythium species found in nursery soils to cause damping-off of tree seedlings. A greenhouse study was conducted to evaluate the pathogenicity and virulence of 44 Pythium isolates representing 16 species that were originally recovered from soil at three forest nurseries in Washington and Oregon. Seeds of Douglas-fir (Pseudotsuga menziesii) were planted into soil infested with each of the isolates. Seedling survival, the number of surviving seedlings with necrotic root lesions, and taproot length were evaluated 4 weeks later. Responses of Douglas-fir to inoculation varied significantly depending on Pythium species and isolate. Eight species (P. dissotocum, P. irregulare, P. aff. macrosporum, P. mamillatum, P. aff. oopapillum, P. rostratifingens, P. sylvaticum, and P. ultimum var. ultimum) significantly reduced the number of surviving seedlings compared to the noninoculated treatment. However, all Pythium species caused a greater percentage of seedlings to develop root lesions (total mean 40%) than was observed from noninoculated seedlings (17%). Taproot length varied little among Pythium treatments and was not a useful character for evaluating pathogenicity. Results confirm the ability of P. irregulare, P. mamillatum, and P. ultimum var. ultimum to cause damping-off of Douglas-fir seedlings, and are indicative that other species such as P. dissotocum, P. aff. macrosporum, P. aff. oopapillum, P. rostratifingens, and P. sylvaticum may also be responsible for seedling loss.

Field performance and early test results of offspring from two Norway spruce seed orchards containing clones transferred to warmer climates

2007 ◽  
Vol 37 (3) ◽  
pp. 515-522 ◽  
Author(s):  
Tore Skrøppa ◽  
Ketil Kohmann ◽  
Øystein Johnsen ◽  
Arne Steffenrem ◽  
Øyvind M. Edvardsen
Keyword(s):  
Norway Spruce ◽  
Field Performance ◽  
Seed Orchard ◽  
Field Trials ◽  
Climatic Conditions ◽  
Test Results ◽  
Seed Orchards ◽  
Low Altitude ◽  
Natural Stands ◽  
Seed Crops

We present results from early tests and field trials of offspring from two Norway spruce ( Picea abies (L.) Karst.) seed orchards containing clones that have been transferred from high altitudes to sea level and from northern to southern latitudes. Seedlings from seeds produced in the low-altitude seed orchard developed frost hardiness later at the end of the growth season, flushed later in field trials, and grew taller than seedlings from seeds produced in natural stands. They had the lowest mortality rate and the lowest frequency of injuries in the field trials. Similar results were observed in seedlings from seeds produced in the southern seed orchard. We found no adverse effects of the changed growth rhythm. Seedlings from two seed crops in the southern orchard, produced in years with a warm and a cold summer, had different annual growth rhythms. The results are explained mainly by the effects of the climatic conditions during the reproductive phase. Seed crops from different years in the same seed orchard may produce seedlings that perform as if they were from different provenances. It is argued that the effects of the climatic conditions during seed production must contribute to the variation among provenances of Norway spruce.

Pythium intermedium. [Descriptions of Fungi and Bacteria].

1964 ◽  
Author(s):  
G. M. Waterhouse
Keyword(s):  
North America ◽  
South America ◽  
Geographical Distribution ◽  
Root Rot ◽  
Crop Plants ◽  
Foot Rot ◽  
Damping Off ◽  
Wide Range

Abstract A description is provided for Pythium intermedium. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On a wide range of hosts represented by the following families: Begoniaceae, Bromeliaceae, Chenopodiaceae, Compositae, Coniferae, Cruciferae, Euphorbiaceae, Geraniaceae, Gramineae, Leguminosae, Liliaceae, Linaceae, Moraceae, Onagraceae, Ranunculaceae, Rosaceae, Solanaceae, Ulmaceae, Violaceae; also in the Equisetales and Filicales. DISEASES: Damping-off of seedlings, foot rot and root rot of ornamentals, occasionally of crop plants and trees. GEOGRAPHICAL DISTRIBUTION: Asia (China); Australia & Oceania (Hawaii); Europe (England, Belgium, France, Germany, Holland, Sweden, U.S.S.R.); North America (U.S.A.); South America (Argentina). TRANSMISSION: A common soil inhabitant.

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