The occurrence of root-infecting fungi and parasitic nematodes in annual Medicago spp. in Western Australian pastures

2000 ◽  
Vol 51 (4) ◽  
pp. 435 ◽  
Author(s):  
M. P. You ◽  
K. Sivasithamparam ◽  
I. T. Riley ◽  
M. J. Barbetti
Keyword(s):  
Western Australia ◽  
Root Rot ◽  
Pathogenic Fungi ◽  
Parasitic Nematodes ◽  
Fungal Isolates ◽  
As Species ◽  
Significant Damage ◽  
Pathogenicity Tests ◽  
Annual Medicago

Asurvey of 30 medic pastures for root-rots was undertaken in Western Australia and pathogenicity tests of representative fungal isolates from roots sampled were conducted to determine the main factors contributing to medic decline and the association between those factors. In particular, the contribution of pathogenic fungi and nematodes to medic root-rot in Western Australia was studied. From a total of 30 000 pieces of root plated, 3836 fungal isolates were obtained and identified at least to genus level. Four hundred and seventy-two representative isolates were tested for in vitro pathogenicity in Medicago sphaerocarpos cv. Orion. Of these, 32 were further tested in the glasshouse. The pathogenicity tests indicated that 56% of isolates were capable of causing significant damage to the root system and it is likely that pathogenic fungi are largely responsible for medic root-rot in the field. In contrast, the number of Pratylenchus spp. in the roots was not found to relate to disease symptoms. It is concluded that soil-borne pathogenic fungi such as species of Pythium, Fusarium, and Phoma contribute significantly to medic pasture decline in Western Australia.

scholarly journals Using Commercial Compost as Control Measures against Cucumber Root-Rot Disease

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Kamel Kamal Sabet ◽  
Magdy Mohamed Saber ◽  
Mohamed Adel-Aziz El-Naggar ◽  
Nehal Samy El-Mougy ◽  
Hatem Mohamed El-Deeb ◽  
...  
Keyword(s):  
Root Rot ◽  
Control Measure ◽  
Disease Incidence ◽  
Pathogenic Fungi ◽  
Pythium Ultimum ◽  
Control Measures ◽  
Infested Soil ◽  
Fungal Isolates ◽  
Cucumber Root

Five commercial composts were evaluated to suppress the root-rot pathogens (Fusarium solani (Mart.) App. and Wr, Pythium ultimum Trow, Rhizoctonia solani Kuhn, and Sclerotium rolfsii Sacc.) of cucumber plants under in vitro and greenhouse conditions. In vitro tests showed that all tested unautoclaved and unfiltrated composts water extracts (CWEs) had inhibitor effect against pathogenic fungi, compared to autoclaved and filtrated ones. Also, the inhibitor effects of 40 bacteria and 15 fungi isolated from composts were tested against the mycelial growth of cucumber root-rot pathogens. Twenty two bacteria and twelve fungal isolates had antagonistic effect against root-rot pathogens. The antagonistic fungal isolates were identified as 6 isolates belong to the genus Aspergillus spp., 5 isolates belong to the genus Penicillium spp. and one isolate belong to the genus Chaetomium spp. Under greenhouse conditions, the obtained results in pot experiment using artificial infested soil with cucumber root-rot pathogens showed that the compost amended soil reduced the percentage of disease incidence, pathogenic fungi population, and improved the cucumber vegetative parameters as shoot length, root length, fresh weight, and dry weight. These results suggested that composts are consequently considered as control measure against cucumber root-rot pathogens.

scholarly journals Isolation, Identification and Biomanagement of Root Rot of Black Cumin (Nigella sativa) Using Selected Bacterial Antagonists

2017 ◽  
Vol 6 (3) ◽  
pp. 47-56 ◽  
Author(s):  
Al-Sman K. Mohamed ◽  
Abo-El-yousr A. M. Kamal ◽  
Eraky Amal ◽  
El-Zawahry Aida
Keyword(s):  
Root Rot ◽  
Nigella Sativa ◽  
Fusarium Spp ◽  
Black Cumin ◽  
Genus Fusarium ◽  
Fungal Isolates ◽  
Fusarium Lateritium ◽  
Pathogenicity Tests ◽  
Causal Pathogen

The study deal with potentiality of some bioagents for controlling the root rot of black cumin under greenhouse conditions, caused by Fusarium spp. Eight fungal isolates were obtained from diseased of back cumin plants collected from Assiut Governorate. These isolates were belonged to the genus Fusarium spp. They were identified as, four isolates of F. comptoceras, three isolates of F. solani and one isolate Fusarium lateritium. Pathogenicity tests indicated that all tested fungal isolates were able to infect black cumin plants causing symptoms of root rot resulted in dwarfism and death before the capsules mature. They varied in their pathogenicity, Fusarium comptoceras No.1 gave the highest percentage of disease severity and percentage of infection on black cumin plants (53 and 50% respectively), while isolates F. comptoceras Nos. 3 and F. solani No. 6 gave the lowest percentage of infection (15 and 17% respectively) the rest of isolates showed moderate of percentage of infection. Antagonistic capability of 15 isolates (PGPR) was tested in vitro against growth of three isolates of Fusarium spp. the causal pathogen of root rot of black cumin. Seeds black cumin plant treated with all bioagents as a suspension significantly increased the root dry weigh and foliar dry weigh compared to infected control. In conclusion, our study confirmed that used of bioagents may be applied as future ecofriendly alternatives to synthetic fungicides for controlling the disease of black cumin.

Virulence and in vitro Characteristics of Pathogenic Fungi Isolated from Soil by Baiting with Coptotermes formosanus (Isoptera: Rhinotermitidae)

2003 ◽  
Vol 38 (3) ◽  
pp. 342-358 ◽  
Author(s):  
Jianzhong Sun ◽  
James R. Fuxa ◽  
Gregg Henderson
Keyword(s):  
Pathogenic Fungi ◽  
Fungal Species ◽  
Coptotermes Formosanus ◽  
Survival Times ◽  
Fungal Virulence ◽  
Fungal Isolates ◽  
Sampling Locations ◽  
Lethal Doses

Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae) was used as “bait” to isolate pathogenic fungi from soil. Ninety soil samples were collected from woodlands and pastures in the vicinities of Baton Rouge, New Orleans, and Lake Charles, LA, from which six Metarhizium anisopliae (Metsch.) Sorokin and nine Beauveria bassiana (Balsamo) Vuillemin isolates were obtained. Numbers of fungal isolates from the three sampling locations did not differ, but more isolates were found in woodlands than in pastures. Median lethal doses (LD50s) of these fungal species to C. formosanus were interspersed, indicating that fungal isolates rather than species had the greatest effect on virulence. Among nine Louisiana and two USDA isolates of B. bassiana, LD50s ranged from 4.95 × 103 to 4.96 × 105 conidia/termite, a difference of 100×. LD50s of six Louisiana and four USDA isolates of M. anisopliae ranged from 7.89 × 103 to 1.22 × 105 conidia/termite. Survival time also was used to compare virulence; M. anisopliae infections caused significantly shorter host survival times than B. bassiana. In vitro growth characteristics were significantly correlated with virulence against termites, suggesting that the characteristics of a fungus growing on agar might contribute to estimating the fungal virulence in vivo.

scholarly journals Characterization and fungicides sensitivity of Phytophthora cinnamomi isolates causing avocado root rot in Zitácuaro, Michoacán

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Alejandra Mondragón-Flores ◽  
Patricia Manosalva ◽  
Salvador Ochoa-Ascencio ◽  
Marlene Díaz-Celaya ◽  
Gerardo Rodríguez-Alvarado ◽  
...  
Keyword(s):  
Growth Rate ◽  
Mating Type ◽  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Potassium Phosphite ◽  
Pathogenicity Tests

<em>Phytophthora cinnamomi</em> is the pathogen most frequently associated with avocado root rot. In Zitácuaro, Michoacán, production has increased by 19.8%; however, there are no studies of root rot in this area. The objective of the study was to characterize the isolates obtained from avocado roots and assess the sensitivity to fungicides. Samples from 5 avocado orchards were collected, sampling 5 trees per orchard (a total of 25 samples). The samples isolated were characterized morphological and molecularly. Mating type was analyzed using reference isolates of<em> P. cinnamomi</em> A1 (isolate from camelia) and A2 (isolate from avocado). To confirm the pathogenicity, tests were performed on avocado fruits with the isolates. The sensitivity of 15 isolates to potassium phosphite and to metalaxyl-M at different concentrations was evaluated<em> in vitro</em>. In a subgroup of six isolates, it was evaluated whether there was a relationship between growth rate and potassium phosphite sensitivity. Fifteen isolates were obtained with coenocytic coraloid mycelium, chlamydospores, sporangia without papilla, ovoid to ellipsoid, with internal proliferation, heterothallic with mating type A2, with amphigynous antheridia and plerotic oospores, characteristics consistent with <em>P. cinnamomi</em>. The inoculated isolates were pathogenic on avocado fruits. The isolates were more sensitive to potassium phosphite than to metalaxyl-M, with mean EC50 values of 24.62 and 0.215 ?g mL-1 of i.a., respectively. No relationship was observed between growth rate and potassium phosphite sensitivity. It is necessary to obtain a greater number of<em> P. cinnamomi</em> isolates for virulence studies.

scholarly journals In vitro: stem cutting a simple technique for determination aggressive potential of fungal isolates causing root rot disease of grapevine

2020 ◽  
Vol 11 (1) ◽  
pp. 141-147
Author(s):  
El- Sayed Hussein Ziedan ◽  
Moataza Mahmoud Saad ◽  
Khames Ahmed Hemida ◽  
Mohamed Abd El- Aziz El -Naggar ◽  
Mostafa Helmy Mostafa ◽  
...  
Keyword(s):  
Root Rot ◽  
Simple Technique ◽  
Stem Cutting ◽  
Root Rot Disease ◽  
Fungal Isolates ◽  
Rot Disease

Bioefficacy of rhizospheric fungal isolates against wilt and root-rot pathogens of Pea

2019 ◽  
Vol 5 (01) ◽  
pp. 133-137
Author(s):  
Rashmi S. Nigam ◽  
R. U. Khan ◽  
Reshu Singh ◽  
Joginder Singh
Keyword(s):  
Root Rot ◽  
Pythium Ultimum ◽  
Culture Technique ◽  
Dual Culture ◽  
Yield And Quality ◽  
Fungal Isolates ◽  
Antagonistic Potential ◽  
Production Areas

Pea (Pisum sativum) is an important leguminous crop in many countries including India. Wilt and root rot of pea is an important and widespread disease that often causes significant reduction in the yield and quality of harvested peas throughout the production areas. It is the most important and widespread disease of pea grown in relatively dry and warm area. In-vitro effectiveness of various antagonistic fungal isolates namely T. harzianum (Th1, Th2, Th3, Th4 and Th5) was evaluated against Fusarium oxysporum f. sp. pisi, Rhizoctonia solani and Pythium ultimum by dual culture technique on potato dextrose agar. According to the observation recorded after 5 days, all the rhizospheric fungal isolates evaluated for their antagonistic potential against wilt and root-rot pathogens, exhibited significant effect on radial growth inhibition of pathogens in comparison to control. Among the fungal isolates, Th3 and Th5 of T. harzianum proved to be most effective in reducing the growth of F. oxysporum f. sp. pisi, R. solani and P. ultimum. It was worthy to note that all rhizospheric fungal isolates visualized an increase in their antagonistic potential over the period of time in subsequent hours of inoculation.

scholarly journals Effect of bio-agents on pathogenic fungi associated with roots of some deciduous fruit transplants and growth parameters in New Valley Governorate, Egypt

2015 ◽  
Vol 55 (2) ◽  
pp. 126-135
Author(s):  
Magd El-Morsi Awad El-Morsi ◽  
Montaser Fawzy Abdel-Monaim
Keyword(s):  
Root Rot ◽  
Growth Parameters ◽  
Pathogenic Fungi ◽  
Dry Weight ◽  
Punica Granatum ◽  
Control Treatment ◽  
Pathogenicity Tests ◽  
Deciduous Fruit ◽  
Number Of Leaves ◽  
Wilt Incidence

Abstract Root rot and wilt disease complex was detected in several fig (Ficus carica L.), grapevine (Vitis vinifera L.), and pomegranate (Punica granatum L.) transplants in nurseries and new orchards of the El-Kharga, Baris, Balate, El-Dakhla, and El-Farafrah districts, of the New Valley governorate, Egypt. The percentage of root rot/wilt incidence and severity on fig, grapevine, and pomegranate transplants in the surveyed districts differed. The average percentages of root rot/wilt incidence and severity, in the surveyed districts, were 41.26, 31.42% in fig, 38.2, 29.5% in grapevine, and 32.1, 23.7% in pomegranate transplants, respectively. The most frequently isolated fungi from rotted roots of fig, grapevine, and pomegranate transplants were Fusarium oxysporum, Rhizoctonia solani, and Macrophomena phaseolina. In pathogenicity tests, all the tested fungi were pathogenic to fig, grapevine, and pomegranate transplants. Under laboratory conditions, all of the following tested bio-agents: Azotobacter sp., Bacillus cereus, B. megaterium, and B. subtilis, were able to inhibit growth of the causal pathogens to different degrees. The effect of these bio-agents individually and/or mixed, when used as a soil drench treatment, were varied in reducing the incidence and severity of root rot/wilt diseases in fig, grapevine, and pomegranate transplants under greenhouse conditions. The mixed bio-agents gave the highest protection against root rot/wilt diseases compared with the individually used of bio-agents. All treatments significantly increased plant height, number of leaves/transplant, leaf area, fresh and dry weight/transplant compared with the control treatment.

scholarly journals An Emerging Strawberry Fungal Disease Associated with Root Rot, Crown Rot and Leaf Spot Caused by Neopestalotiopsis rosae in Mexico

Plant Disease ◽  
2020 ◽  
Vol 104 (8) ◽  
pp. 2054-2059 ◽  
Author(s):  
Angel Rebollar-Alviter ◽  
Hilda Victoria Silva-Rojas ◽  
Dionicio Fuentes-Aragón ◽  
Uriel Acosta-González ◽  
Merari Martínez-Ruiz ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Root Rot ◽  
Phylogenetic Reconstruction ◽  
Elongation Factor ◽  
Fungal Disease ◽  
Crown Rot ◽  
Internal Transcribed Spacer Region ◽  
Pathogenicity Tests ◽  
Vitro Effect

In the 2017 strawberry season, several transplant losses reaching 50% were observed in Zamora, Michoacán Valley, Mexico, due to a new fungal disease associated with root rot, crown rot, and leaf spot. In this year the disease appeared consistently and increased in the following seasons, becoming a concern among strawberry growers. Thus, the aim of this research was to determine the etiology of the disease and to determine the in vitro effect of fungicides on mycelial growth of the pathogen. Fungal isolates were obtained from symptomatic strawberry plants of the cultivars ‘Albion’ and ‘Festival’ and were processed to obtain monoconidial isolates. Detailed morphological analysis was conducted. Concatenated phylogenetic reconstruction was conducted by amplifying and sequencing the translation elongation factor 1 α, β-tubulin partial gene, and the internal transcribed spacer region of rDNA. Pathogenicity tests involving inoculation of leaves and crowns reproduced the same symptoms as those observed in the field, fulfilling Koch’s postulates. Morphology and phylogenetic reconstruction indicated that the causal agent of the described symptoms was Neopestalotiopsis rosae, marking the first report anywhere in the world of this species infecting strawberry. N. rosae was sensitive to cyprodinil + fludioxonil, captan, iprodione, difenoconazole, and prochloraz.

scholarly journals In vitro Potential of Aqueous Extracts of Plant Leaves to inhibit Pathogenic Fungi

2018 ◽  
pp. 1-18
Author(s):  
Liamngee Kator ◽  
Zakki Yula Hosea
Keyword(s):  
Growth Inhibition ◽  
Aspergillus Flavus ◽  
Leaf Extract ◽  
Pathogenic Fungi ◽  
Inhibitory Effect ◽  
Aqueous Extracts ◽  
Plant Leaves ◽  
Fungal Isolates ◽  
Alternative Means

The in vitro potential of aqueous extracts of plant leaves to inhibit pathogenic fungi was carried out. The effect of leaf extract and concentration on growth inhibition of organism I (Aspergillus flavus) in vitro revealed that a concentration of 100g/mL, Moringa oleifera leaf extract (MLE) gave the highest growth inhibition of  (59.14) followed by Neem (Azadirachta indica) leaf extract (NLE) (49.70) and Bitter leaf (Vernonia amygdalina)  extract (BLE) (45.84) respectively while the least growth inhibition on organism 1 (Aspergillus flavus) was by MLE at concentration of 40 g/mL (30.11) followed by NLE at 60 g/mL (32.11) and BLE at 40 g/mL (40.13). On organism 2 (Penicillium waksmanii), MLE at a concentration of 100 g/mL gave the highest growth inhibition of (50.49) followed by NLE (49.01) and BLE (36.72) respectively while the least inhibition on growth of organism 2 in vitro was by BLE at concentration of 60 g/mL (16.05) followed by MLE (40.70) and NLE (40.70) at concentration of 80 g/mL respectively. On organism 3 (Botryodiplodia theobromae), MLE at  concentration of 100 g/mL gave the highest inhibition of growth (57.00) followed by NLE (52.71) and BLE (50.15) respectively while  the least inhibition on growth of organism 3 in vitro was by BLE at 40 g/mL (21.50) followed by MLE at 60 g/mL (31.06) and NLE at 40 g/mL (41.89). On organism 4 (Fusarium oxysporum), the highest growth inhibition was by MLE at 100g/mL (54.02) followed by NLE at 100 g/mL (49.62) and BLE at 100 g/mL (44.41) while MLE showed the least growth inhibition at 60 g/mL (24.04) followed by BLE at 40 g/mL  (26.60) and NLE at 40 g/mL (30.12). NLE showed the highest grand inhibitory effect of extract concentration on growth inhibition of organism 5 (Colletotrichum asianum) in vitro at 100 g/mL (53.68) followed by MLE at 100 g/mL (51.51) and BLE at 100 g/mL (40.94). The least inhibitory effect on the growth of organism 5 in vitro was by BLE at 80 g/mL (21.26) followed by NLE at 40 g/mL (22.25) and MLE at 40 g/mL (32.69). The controls ranged from 2.23 to 4.31 across all extract concentrations and fungal isolates. There were significant differences in growth inhibition between extract concentrations and their controls on all fungal isolates. The use of plant extracts provides alternative means for controlling plant pathogenic fungi.

Root rot caused by Pythium irregulare Buisman, an important factor in the decline of established subterranean clover pastures

1974 ◽  
Vol 25 (4) ◽  
pp. 537 ◽  
Author(s):  
GE Stovold
Keyword(s):  
Root Rot ◽  
Subterranean Clover ◽  
Common Disease ◽  
Crop Species ◽  
Pythium Irregulare ◽  
Factors Affecting ◽  
South Wales ◽  
Matter Production ◽  
Pathogenicity Tests

The problem of poor re-establishment and poor seasonal production in long-term subterranean clover pastures has been recognized for some time, particularly on the Southern Tableland and Slopes regions of New South Wales. Field and laboratory investigations showed that rotting of the lateral feeder roots was a common disease of subterranean clover during the cool part of the growing season. Isolations made from diseased roots yielded a predominance of Pythium spp. of which Pythiurn irregulare was the most common. Pathogenicity tests demonstrated that P. irregulare consistently caused damping-off of germinating subterranean clover. This fungus also infected established plants and at low temperatures caused severe reduction of dry matter production. Symptoms produced on artificially inoculated plants were identical with those observed on plants infected in the field. Soil moisture and the level of fungal inoculum added did not have a critical effect on the severity of root disease. A range of other important pasture and crop species were also artificially infected with P. irregulare, with resulting necrosis of feeder roots. In vitro studies of factors affecting the growth of P. irregulare showed that this pathogen was well adapted to survive and cause disease in cold wet soils, the conditions most favourable for root rot in the field. The importance of P. irregulare as a pathogen of established plants and possible means of reducing its effect on the growth of subterranean clover are discussed.

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