FUNGOUS ROOT ROTS OF THE STRAWBERRY

1934 ◽  
Vol 11 (1) ◽  
pp. 1-17 ◽  
Author(s):  
J. H. L. Truscott
Keyword(s):  
Seasonal Variations ◽  
Root Rot ◽  
Mycorrhizal Fungus ◽  
Artificial Inoculation ◽  
Microscopical Examination ◽  
Relative Importance ◽  
Root Rots ◽  
Growing Seasons ◽  
Obligate Parasites ◽  
Wild Strawberry

This paper reports the results of two years of investigation at the Horticultural Experiment Station at Vineland, Ontario, on fungi associated with the root rot of strawberries. Roots from the field were collected periodically throughout two growing seasons and were studied by direct microscopical examination and by plating methods. Hundreds of isolates from diseased roots were tested by artificial inoculation of strawberry roots, and the primary parasites were further studied. These were classed in the following genera: Pythium, Fusarium, Alternaria, Ramularia, Rhizoctonia, Verticillium and Cylindrocladium. Microscopical examination revealed three additional forms, Asterocystis, a Plasmodiophoraceous fungus and the Phycomycetous mycorrhizal fungus, which are obligate parasites of Phycomycetous type. Some of the fungi occurred more frequently than others, and there were seasonal variations in the activity of most of them. A similar root flora was encountered in wild strawberry roots, so that most of these fungi are probably indigenous. Their relative importance can be determined only by several years of observation of field material.

scholarly journals An Extract Purified from the Mycelium of a Tomato Wilt-Controlling Strain of Fusarium sambucinum Can Protect Wheat against Fusarium and Common Root Rots

Pathogens ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 61 ◽  
Author(s):  
Larisa Shcherbakova ◽  
Tatyana Nazarova ◽  
Oleg Mikityuk ◽  
Ekaterina Istomina ◽  
Tatyana Odintsova
Keyword(s):  
Root Rot ◽  
Bipolaris Sorokiniana ◽  
Field Trials ◽  
Gel Chromatography ◽  
Common Root ◽  
Root Rots ◽  
Growing Seasons ◽  
Mycelial Extract ◽  
Small Plot ◽  
Tomato Wilt

An approach to manage seed-transmitted Fusarium crown-foot-root rot (FCR, Fusarium spp.) and common root rot (CRR, Bipolaris sorokiniana) on wheat, avoiding environmental risks of chemicals, is seed treatments with microbial metabolites. F. sambucinum strain FS-94 that induces resistance to tomato wilt was shown by this study to be a source of non-fungitoxic wheat-protecting metabolites, which were contained in a mycelium extract purified by gel-chromatography and ultrafiltration. Plant-protecting effect of the purified mycelial extract (PME) was demonstrated in vegetation experiments using a rolled-towel assay and by small-plot field trials. To elucidate mechanisms putatively underlying PME protective activity, tests with cultured Triticum aestivum and T. kiharae cells, particularly the extracellular alkalinization assay, as well as gene expression analysis in germinated wheat seeds were used. Pre-inoculation treatments of seeds with PME significantly decreased the incidence (from 30 to 40%) and severity (from 37 to 50%) of root rots on seedlings without any inhibition of the seed germination and potentiation of deoxynivalenol (DON), DON monoacetylated derivatives and zearalenon production in FCR agents. In vegetation experiments, reductions in the DON production were observed with doses of 0.5 and 1 mg/mL of PME. Pre-sowing PME application on seeds of two spring wheat cultivars naturally infected with FCR and CRR provided the mitigation of both diseases under field conditions during four growing seasons (2013–2016). PME-induced ion exchange response in cultured wheat cells, their increased survivability, and up-regulated expression of some defensins’ genes in PME-exposed seedlings allow the suggestion of the plant-mediated character of disease-controlling effect observed in field.

ROOT ROTS OF THE RASPBERRY

1936 ◽  
Vol 14c (8) ◽  
pp. 306-317 ◽  
Author(s):  
G. H. Berkeley
Keyword(s):  
British Columbia ◽  
Rhizoctonia Solani ◽  
Microscopic Examination ◽  
Root Rot ◽  
Mycorrhizal Fungus ◽  
Root Rots ◽  
Pure Cultures ◽  
Fusarium Sp ◽  
Fraser Valley ◽  
Apparently Healthy

The investigations reported here are concerned with isolations from diseased raspberry roots, preliminary inoculations with isolates, and microscopic examination of naturally and artificially infected roots.The following fungi were isolated from naturally infected roots: Coniothyrium Fuckelii, Cylindrocarpon radicicola, Fusarium sp., possibly F. orthoceras, Cylindrocladium sp., Pythium spp., Rhizoctonia Solani, Rhizoctonia sp. (orchid type), and in preliminary inoculation experiments each fungus was found to be capable of producing necrotic lesions on healthy roots. Microscopic examinations of roots artificially inoculated with pure cultures of the above fungi, showed in the roots the presence of the fungus used for inoculation. In addition the "phycomycetous mycorrhizal" fungus already associated with root rot of strawberries and tobacco was observed to be almost always present in roots of affected raspberry plants, and, to a lesser extent, in apparently healthy roots from apparently normal plants. Nematodes, especially Anguillulina pratensis, the meadow nematode, were present in and on roots from certain soils, while they were absent from roots from other soils. Strawberry and raspberry seeds were sown in sterilized and non-sterilized affected soil with the result that the roots in sterilized soil appeared to be healthy, while those in the non-sterilized soil became affected with necrotic lesions.Evidence is given which shows not only that certain symptoms of raspberry root rot are similar to the symptoms of strawberry root rot, which is considered to be a major factor in the degeneration of strawberries in both Europe and America, but also that many of the fungi and nematodes generally conceded to be associated with root rots of strawberry are likewise associated with root rots of raspberry. In the Fraser Valley, British Columbia, where certain raspberry plantations appear to be heavily infected with root rots, the possibility that these root rots may play an important role in connection with the un-thriftiness of such plantations should not be overlooked.

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.

Observations on the Seasonal Development of the Grass Heteropogon contortus Infected by the Smut Sorosporium caledonicum

1975 ◽  
Vol 23 (1) ◽  
pp. 45 ◽  
Author(s):  
RA Fullerton
Keyword(s):  
Seasonal Development ◽  
Relative Importance ◽  
Heteropogon Contortus ◽  
Growing Seasons

The tillering behaviour of tussocks of Heteropogon contortus infected by Sorosporiwm caledonicum has been observed over three consecutive growing seasons. It has been established that infected tussocks may bear both smutted and flowering tillers in the course of a season. Some of the flowering tillers contain smut mycelium and are a source of smutted tillers in the following season. The relative importance of the various kinds of tiller to the longevity of the host and parasite is discussed.

Incidence of root and hypocotyl diseases in lupin crops in Western Australia between 1986 and 2005

2010 ◽  
Vol 61 (3) ◽  
pp. 241 ◽  
Author(s):  
G. J. Thomas ◽  
W. J. MacLeod ◽  
M. W. Sweetingham
Keyword(s):  
Crop Rotation ◽  
Western Australia ◽  
Root Rot ◽  
Plant Density ◽  
Management Systems ◽  
Sowing Depth ◽  
Root Rots ◽  
The Past ◽  
Predominant Pathogen ◽  
Growing Region

Three separate surveys were carried out in commercial lupin crops in the major lupin growing region of Western Australia in 1986, 1990, and 2004–05. In total, 333 sites were sampled and plants assessed for the incidence and cause of root and hypocotyl rots. Measurements were made of plant density and sowing depth at all sites. In all surveys, root rot was more common than hypocotyl rot. Root rot occurred in more than 95% of sites in each survey; however, a greater proportion of sites had high levels of root rot in early surveys. The incidence of root rot within sites decreased from an average of 34.9% in 1986 to 10.2% in 2004–05. Hypocotyl rot incidence varied among surveys, incidence of infected paddocks, and within-paddock incidence was greatest in the 1990 survey. Hypocotyl rot incidence was lowest in the 2004–05 survey. Rhizoctonia solani and Pleiochaeta setosa were commonly isolated from root lesions and R. solani was the predominant pathogen isolated from hypocotyl lesions. Analysis of the R. solani isolates by pectic zymogram showed that the ZG3 strain was most regularly isolated from roots and hypocotyls. This series of surveys indicates that the incidence of root rots in commercial lupin paddocks in Western Australia has decreased dramatically over the past 20 years; however, root rot still occurs in most paddocks regardless of soil type, location, crop rotation, and management systems.

scholarly journals Evaluation of Various Sources of Viral Infection in Strawberry Fields of Quebec, Canada

2019 ◽  
Vol 112 (6) ◽  
pp. 2577-2583
Author(s):  
Phanie Bonneau ◽  
Richard Hogue ◽  
Stéphanie Tellier ◽  
Valérie Fournier
Keyword(s):  
Insect Vectors ◽  
Relative Importance ◽  
Fragaria Ananassa ◽  
Viral Contamination ◽  
Persistent Viruses ◽  
Strawberry Vein Banding Virus ◽  
Before And After ◽  
Fragaria Virginiana ◽  
Wild Strawberry ◽  
Sources Of Contamination

Abstract The decline of cultivated strawberry (Fragaria × ananassa Duchesne ex Rozier; Rosaceae) observed in the province of Quebec, Canada, between 2012 and 2014 was mostly caused by persistent viruses: strawberry mild yellow edge virus (SMYEV) (Potexvirus; Alphaflexiviridae) and strawberry crinkle virus (SCV) (Cytorhabdovirus; Rhabdoviridae); and semi-persistent viruses: strawberry mottle virus (SmoV) (Secoviridae), strawberry vein banding virus (SVBV) (Caulimovirus; Caulimoviridae), and strawberry pallidosis virus (SPaV) (Crinivirus: Closteroviridae) transmitted by insect vectors. The objective of this study was to determine the sources of viral contamination in commercial strawberry fields in Quebec. Specifically, we wished to 1) determine the prevalence of persistent viruses in winged strawberry aphid Chaetosiphon fragaefolii (Cockerell) (Hemiptera: Aphididae) specimens captured; 2) determine the prevalence of all viruses in wild strawberry Fragaria virginiana Miller plants near commercial plantings; and 3) evaluate the viral contamination of strawberry transplants obtained from nurseries and tested before and after planting in commercial strawberry fields. Results indicated high percentage (38%) of the aphids (n = 205) and high percentage (67%) of F. virginiana patches (n = 12) were infected by strawberry viruses. Ultimately, our results showed a low percentage (5%) of the plants from various nurseries (n = 56) were infected before planting, whereas a third (29%) of the healthy exposed plants in the fields (n = 96) became rapidly infected by insect vectors within a year of having been planted. This study provides significant insights on the relative importance of the various sources of contamination in Quebec strawberry fields: C. fragaefolii versus F. virginiana versus nurseries versus post-nursery infections through exposure to virus-carrying insects.

Sign in / Sign up

Export Citation Format

Share Document