scholarly journals Seed Treatment with a Fungal or a Bacterial Antagonist for Reducing Corn Damping-off Caused by Species of Pythium and Fusarium

Plant Disease ◽  
1997 ◽  
Vol 81 (5) ◽  
pp. 450-454 ◽  
Author(s):  
W. Mao ◽  
J. A. Lewis ◽  
P. K. Hebbar ◽  
R. D. Lumsden
Keyword(s):  
Plant Height ◽  
Root Rot ◽  
Burkholderia Cepacia ◽  
Incubation Temperature ◽  
Trichoderma Viride ◽  
Pythium Ultimum ◽  
Infested Soil ◽  
Damping Off ◽  
Fresh Weight ◽  
Plant Emergence

Bioassays were conducted under greenhouse conditions to test the efficacy of antagonists applied to corn (Zea mays) seed for protection against seed rot and seedling damping-off at 18 and 25°C in a field soil artificially infested with a combination of Pythium ultimum, P. arrhenomanes, and Fusarium graminearum. Biomass of Gliocladium virens isolates Gl-3 or Gl-21, Trichoderma viride isolate Tv-1, or peat-based slurry of Burkholderia cepacia isolates Bc-B, Bc-T, or Bc-1 was coated individually onto corn seeds in one test, and Gl-3 or Bc-B at four inoculum levels was used in another test. Seed treatments with most of the biocontrol agents, as well as with the fungicide captan, significantly (P ≤ 0.05) increased seedling stand, plant height and fresh weight, and decreased root rot severity compared with untreated seeds in pathogen-infested soil. Coating seeds with the biocontrol fungus G. virens isolate Gl-3 was the most effective treatment, resulting in greater (P ≤ 0.05) seedling stand, plant height, and fresh weight, and lower (P ≤ 0.05) severity of root rot than those parameters from seeds treated with captan or other antagonists at both temperatures. The results from the seeds treated with Gl-3 were similar to those of untreated seeds in noninfested soil. In treatments with Bc-1, Bc-T, Bc-B, or Tv-1, incubation temperature affected plant emergence, root rot severity, plant height, and fresh weight (P ≤ 0.01). Conversely, in seeds coated with Gl-3 or Gl-21, these parameters were similar at both temperatures. The minimum number of propagules needed per corn seed to obtain plant emergence comparable to that from captan-treated seeds was between 104 and 105 CFU for Gl-3 and >108 for Bc-B. When propagules of Gl-3 were applied at a rate >106 CFU per seed, seedling emergence was greater (P ≤ 0.05) than that from captan-treated seeds.

scholarly journals Seed Treatment Using Pre-infiltration and Biocontrol Agents to Reduce Damping-off of Corn Caused by Species of Pythium and Fusarium

Plant Disease ◽  
1998 ◽  
Vol 82 (3) ◽  
pp. 294-299 ◽  
Author(s):  
W. Mao ◽  
R. D. Lumsden ◽  
J. A. Lewis ◽  
P. K. Hebbar
Keyword(s):  
Disease Control ◽  
Plant Height ◽  
Root Rot ◽  
Seed Treatment ◽  
Pythium Ultimum ◽  
Biocontrol Agents ◽  
Infested Soil ◽  
Damping Off ◽  
Fresh Weight ◽  
Inoculum Rate

Bioassays were conducted in a greenhouse at 18°C to determine the effectiveness of a seed treatment used in combination with biocontrol agents for the reduction of corn damping-off caused by species of Pythium and Fusarium. Corn seeds were infiltrated with tap water, drained, air-dried, and then coated with biomass of an antagonistic fungus, Gliocladium virens isolate Gl-3, or an antagonistic bacterium, Burkholderia cepacia isolates Bc-B or Bc-1, or a combination of Gl-3 with each of the bacterial isolates. A nonsterile field soil was infested with a combination of pathogens: Pythium ultimum, P. arrhenomanes, and Fusarium graminearum at 2 inoculum rates (1× and 4×). Pre-infiltration enhanced (P ≤ 0.05) disease control with most treatments at both inoculum rates. Treatments with biocontrol agents alone or in combination, as well as the fungicide captan, effectively reduced the disease at a pathogen inoculum rate of 1×, resulting in greater (P ≤ 0.05) seedling stands, plant height, and fresh weight, and lower (P ≤ 0.05) root rot severity compared with untreated seeds in infested soil. At a pathogen inoculum rate of 4×, stands were lower (P ≤ 0.01) and root-rot severity was higher (P ≤ 0.01) compared to those at 1× for all treatments. Nevertheless, coating seeds with all biocontrol agents (alone or in combination), except with Bc-1 alone, reduced disease (P ≤ 0.05) compared to untreated seeds in infested soil. At both inoculum rates of 1× and 4×, coating seeds with Gl-3 + Bc-B was more effective (P ≤ 0.05) in disease control than any other treatment, resulting in stands, growth rate (plant height and fresh weight), and root rot severity similar to plants from untreated seeds in noninfested soil. In addition, when the exudate from a 2-h infiltration of corn seed was added to the seeds during seed coating, seedling stand was often lower and root rot severity was often higher than those from infiltrated seeds (P ≤ 0.05). These results indicated that the infiltration process removed certain exudates, including nutrients and/or stimulants (not detected in this study) that might be utilized by pathogens to initiate seed infection. A thin-layer chromatography (TLC) profile of the exudates showed the presence of eight amino acids and three major carbohydrates.

scholarly journals First Report of a Ceratobasidium sp. Causing Root Rot on Canola in Washington State

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 591-591 ◽  
Author(s):  
K. L. Schroeder ◽  
T. C. Paulitz
Keyword(s):  
Plant Height ◽  
Root Rot ◽  
Root Zone ◽  
Dry Weight ◽  
Washington State ◽  
Infested Soil ◽  
Damping Off ◽  
Root Tips ◽  
Hordeum Vulgare L ◽  
First Report

Rhizoctonia root rot occurs commonly on canola (Brassica napus L.) in Washington State. Recently, isolates of an additional pathogen were found to be involved in this disease complex. Isolates of an AG-I-like Ceratobasidium sp. were collected from roots and root zone soil in central Washington near Ritzville. Identity of selected isolates was verified by sequencing the internal transcribed spacer (ITS) region of the rDNA (GenBank Accession Nos. JQ247570, JQ247571, and JQ247572), with a 90 to 93% identity to AG-I. All isolates also amplified with AG-I-like specific primers (1). Six isolates were included in pathogenicity assays conducted in the greenhouse. There were five replicates of three plants for each treatment and the experiment was conducted twice. Pasteurized soil was infested with ground oat inoculum (1%) and placed into containers (3.8 × 21 cm). Infested soils were seeded with canola, chickpea (Cicer arietinum L.), lentil (Lens culinaris Medik.), pea (Pisum sativum L.), barley (Hordeum vulgare L.), or wheat (Triticum aestivum L.). After 3 weeks of incubation at 15°C, the plants were destructively harvested. The emergence of canola was consistently reduced in soil infested with a Ceratobasidium sp., with reductions of 0 to 23% (average 11%). There was no postemergence damping-off, a symptom commonly associated with AG-2-1 (2). Plant height and top dry weights were significantly reduced for canola seeded into infested soil. Heights of plants growing in infested soil was reduced by 25 to 53% (average 42%) and top dry weight was reduced by 37 to 81% (average 61%) compared with the noninfested control. The legume hosts tested in this study were also affected by this Ceratobasidium sp., but to a lesser extent. Compared with the noninfested controls, there was evidence of preemergence damping-off in chickpea (0 to 27%, average 13%) and pea plants were consistently stunted (5 to 23%, average 12%). Chickpea and pea plants grown in infested soil also had reduced top dry weights of 9 to 28% (average 17%) and 13 to 35% (average 21%), respectively. The roots of all infected hosts had a characteristic brown discoloration with tapered, rotted root tips (spear tips). There was no reduction in emergence or plant height of wheat and barley; there was inconsistent reduction in dry weight of these plants. To our knowledge, this is the first report of a Ceratobasidium sp. causing disease on canola in Washington State. References: (1) P. A. Okubara et al. Phytopathology 98:837, 2008. (2) T. C. Paulitz et al. Plant Dis. 90:829, 2006.

scholarly journals First Report of Root Rot Caused by Rhizoctonia solani AG-10 on Canola in Washington State

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 584-584 ◽  
Author(s):  
K. L. Schroeder ◽  
T. C. Paulitz
Keyword(s):  
Rhizoctonia Solani ◽  
Plant Height ◽  
Root Rot ◽  
Root Zone ◽  
Lateral Roots ◽  
Washington State ◽  
Infested Soil ◽  
Damping Off ◽  
Hordeum Vulgare L ◽  
First Report

Canola (Brassica napus L) production has gained renewed interest in Washington State over the past few years, primarily for the purpose of producing biofuel. Plants were observed to be showing symptoms of Rhizoctonia root rot and postemergence damping-off. In many cases, this was due to Rhizoctonia solani AG-2-1, which was previously documented (4). However, additional plants were occasionally observed that were stunted and had reduced vigor, but lacked the distinctive severe stem damage and postemergence damping-off, which are both symptoms of infection with R. solani AG-2-1. Isolates of R. solani AG-10 were collected from symptomatic plants or baited from root zone soil at various dryland production locations in eastern Washington, including sites near Colfax, Pullman, and Walla Walla. Initial identification was determined by quantitative (Q)-PCR using R. solani AG-10 specific primers (3). The identity was verified by sequencing random isolates identified by Q-PCR (GenBank Accessions Nos. JQ068147, JQ068148 and JQ068149). All sequenced isolates had 99% identity to previously reported isolates of R. solani AG-10. Six isolates were chosen to test pathogenicity on canola plants in the greenhouse. Sterilized oats were inoculated with each of six isolates of R. solani AG-10 and grown for 4 weeks. The soil was infested with ground oat inoculum (1% wt/wt) and spring canola cv. Sunrise was seeded into 3.8 × 21-cm containers. After 3 weeks of incubation at 15°C, plants were harvested and assessed. Emergence was reduced in the infested soil with 73 to 93% (average 81%) emergence compared with 100% emergence in the noninfested soil. There was no evidence of postemergence damping-off. However, all six isolates of R. solani AG-10 significantly reduced the plant height and top dry weights compared with the noninfested controls. The plant height in infested soil was 28 to 42% (average 34%) shorter and top dry weights were 37 to 70% (average 54%) lower than in noninfested soil. Roots of infected plants had a light brown discoloration along with reduced length and fewer lateral roots. Additional host plants were tested, including wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), pea (Pisum sativum L.), chickpea (Cicer arietinum L.), and lentil (Lens culinaris Medik.). There was no significant reduction in plant height or plant dry weight for any of these hosts. R. solani AG-10 was previously found to be weakly virulent on canola and other cruciferous hosts in Australia (1,2). To our knowledge, this is the first report of R. solani AG-10 causing disease on canola in Washington State. Reference: (1) R. K. Khangura et al. Plant Dis. 83:714, 1999. (2) G. C. MacNish et al. Australas. Plant Pathol. 24:252, 1995. (3) P. A. Okubara et al. Phytopathology 98:837, 2008. (4) T. C. Paulitz et al. Plant Dis. 90:829, 2006.

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.

Gliovirin, a new antibiotic from Gliocladium virens, and its role in the biological control of Pythium ultimum

1983 ◽  
Vol 29 (3) ◽  
pp. 321-324 ◽  
Author(s):  
Charles R. Howell ◽  
Robert D. Stipanovic
Keyword(s):  
Pythium Ultimum ◽  
Similar Efficacy ◽  
Antibiotic Activity ◽  
Infested Soil ◽  
Damping Off ◽  
Potato Dextrose Broth ◽  
Seedling Disease ◽  
X Ray ◽  
Gliocladium Virens ◽  
Induced Mutant

A compound with antibiotic activity toward Pythium ultimum was isolated from potato dextrose broth shake cultures of Gliocladium virens, a common soil mycoparasite known to inhibit but not parasitize P. ultimum. The mass spectrum and an X-ray crystallograph of the purified antibiotic indicated that it was a new diketopiperazine, and we have given it the trivial name gliovirin. Gliovirin is highly toxic to P. ultimum but is inactive against other fungi associated with cotton seedling disease. The antibiotic does not persist in nonsterile soil where it is apparently inactivated by the soil microflora.An ultraviolet light induced mutant of G. virens deficient for gliovirin production was overgrown by P. ultimum in culture and did not protect cotton seedlings from damping-off in P. ultimum infested soil. A mutant with enhanced gliovirin production was more inhibitory to P. ultimum in culture than the parent isolate and showed similar efficacy as a seedling disease suppressant, even though its growth rate was reduced when compared to the parent isolate. These results indicate that gliovirin may be important to the antagonist–pathogen interaction.

scholarly journals The Effect of Pythium ultimum and Soil Flooding on Two Soybean Cultivars

Plant Disease ◽  
2006 ◽  
Vol 90 (5) ◽  
pp. 597-602 ◽  
Author(s):  
M. T. Kirkpatrick ◽  
C. S. Rothrock ◽  
J. C. Rupe ◽  
E. E. Gbur
Keyword(s):  
Plant Height ◽  
Growth Stage ◽  
Soil Layer ◽  
Dry Weight ◽  
Pythium Ultimum ◽  
Height Growth ◽  
Root Weight ◽  
Infested Soil ◽  
Soil Flooding ◽  
Top Dry Weight

The effect of flooding and Pythium ultimum on soybean, Glycine max, was determined in a series of greenhouse experiments using the cultivars Hutcheson and Archer. Seeds were planted into pasteurized soil either not infested or infested with sand-cornmeal inoculum of P. ultimum and either flooded at emergence for 2 days or at the four leaf node stage (V4) for 5 days. A nonflooded control was included in each experiment. Seeds placed directly into infested soil resulted in little or no stand for Hutcheson regardless of flood treatment, whereas stand was reduced for Archer only in the flooded infested soil treatment. Additional experiments were conducted by placing seed onto a 2- to 5-mm layer of pathogen-free soil on top of the infested soil. Flooding at emergence reduced plant height, growth stage, and top dry weight for Hutcheson and root fresh weight for both cultivars. Greater reductions for Hutcheson in root weight, and top dry weight in P. ultimum-infested soil in the soil layer experiments, also indicated that Hutcheson was more susceptible than Archer. Flooding alone decreased root weights, and infestation with P. ultimum reduced weights further resulting in an additive effect. This also was the case for plant height, growth stage, and top dry weight for Hutcheson for flooding at emergence. Root discoloration was greatly increased for both cultivars in infested soil flooded at emergence. Similar results were found when plants were flooded at V4; however, the effect was not as great as with flooding at emergence. These studies indicate that Pythium damping-off and root rot may account for a portion of the negative response of soybean to flooding. The results also indicate that Archer has some resistance to P. ultimum.

scholarly journals Resistance of the Soybean Cultivar Archer to Pythium Damping-Off and Root Rot Caused by Several Pythium spp.

Plant Disease ◽  
2008 ◽  
Vol 92 (5) ◽  
pp. 763-766 ◽  
Author(s):  
G. D. Bates ◽  
C. S. Rothrock ◽  
J. C. Rupe
Keyword(s):  
Root Rot ◽  
Seed Quality ◽  
Developmental Stages ◽  
Pythium Ultimum ◽  
Soybean Cultivar ◽  
Damping Off ◽  
Maturity Group ◽  
Group V ◽  
Disease Symptoms ◽  
Group I

Archer, a maturity group I soybean cultivar with demonstrated flood tolerance and resistance to Pythium ultimum, was compared with Hutcheson, a widely planted maturity group V cultivar in Arkansas, for resistance to P. ultimum, P. irregulare, P. aphanidermatum, P. vexans, and group HS. Emergence and establishment assays demonstrated that Archer had greater emergence and fewer disease symptoms after 10 days for all pathogenic species of Pythium than did Hutcheson. Archer also demonstrated higher root weights and fewer disease symptoms compared with Hutcheson in assays conducted for 6 weeks. Similar results were found using two different seed lots of the cultivars, suggesting that the results were not due to seed quality differences. This study indicates that resistance in Archer to Pythium damping-off and root rot compared with Hutcheson is robust, with efficacy over a number of Pythium spp. and a range of plant developmental stages.

A NEW PSYCHROPHILIC FUNGUS CAUSING GERMINATION FAILURE OF CONIFER SEEDS

1964 ◽  
Vol 42 (12) ◽  
pp. 1589-1604 ◽  
Author(s):  
Z Epners
Keyword(s):  
Root Rot ◽  
Picea Glauca ◽  
Pinus Strobus ◽  
Pinus Resinosa ◽  
Infested Soil ◽  
Damping Off ◽  
Conifer Seeds ◽  
Psychrophilic Fungus ◽  
Favorable Conditions ◽  
Germinated Seeds

The germination of coniferous seeds has been very low for several years at the Province of Ontario Nurseries located at Midhurst and Orono, in extreme cases being reduced to only 2%.Between 1959 and 1963 seeds which had failed to germinate were collected from beds of Pinus resinosa Sol., Pinus sylvestris L., Pinus strobus L., and Picea glauca (Moench.) Voss. From all such seeds tested a psychrophilic fungus was isolated, which grows between −1 and 27 °C but does not grow at 30 °C. In such non-germinated seeds the fungus is found in all cells of the endosperm and embryo, but instead of rotting the seeds, it mummifies them. The fungus was found in a viable state in infected seed [Formula: see text] years after these were sown.The fungus has not yet been identified and no record has been found of its previous isolation. In this work it has been called the seed-fungus (S-fungus). It is not a damping-off fungus since it does not kill the seedlings before or as they emerge from the soil and, even when seedling stems are soft and succulent, it does not cause root rot or top killing. Under favorable conditions the fungus may kill 100% of conifer seeds in infested soil. Control was achieved through pelleting the seeds with Captan.The fungus produces sympodiospores and has some affinity with the genera Costantinella and Nodulisporium, but differs significantly from them.

scholarly journals Mycofumigation with Muscodor albus and Muscodor roseus for Control of Seedling Diseases of Sugar Beet and Verticillium Wilt of Eggplant

Plant Disease ◽  
2003 ◽  
Vol 87 (11) ◽  
pp. 1349-1354 ◽  
Author(s):  
A. M. Stinson ◽  
N. K. Zidack ◽  
G. A. Strobel ◽  
B. J. Jacobsen
Keyword(s):  
Sugar Beet ◽  
Solanum Melongena ◽  
Pythium Ultimum ◽  
Potato Dextrose Agar ◽  
Infested Soil ◽  
Damping Off ◽  
Stand Establishment ◽  
Aphanomyces Cochlioides ◽  
Alginate Capsules ◽  
Antimicrobial Volatiles

Mycofumigation is the use of antimicrobial volatiles produced by fungi such as Muscodor albusitalic and M. roseus for the control of other organisms. Sugar beet (Beta vulgaris L.) stand establishment was increased and disease severity decreased by mycofumigation with M. roseus and M. albus in autoclaved soil infested with Rhizoctonia solani, Pythium ultimum, or Aphanomyces cochlioides. Eggplant seedlings (Solanum melongena L.) transplanted into autoclaved soil infested with Verticillium dahliae and mycofumigated with M. albus and M. roseus had significantly less disease (P < 0.05) after 4 and 5 weeks compared with nonmycofumigated Verticillium-infested soil. The effect of formulation on efficacy of mycofumigation with M. roseus was tested using potato dextrose agar strips, alginate capsules, ground barley, pesta granules, and stabileze granules. The stabileze and ground barley formulations of M. roseus resulted in the best control of P. ultimum damping-off. The best control of A. cochlioides damping-off was with the stabileze formulation, and the stabileze, ground barley, and agar strip formulations provided similar control of R. solani damping-off. In soil infested with P. ultimum, mycofumigation with M. albus stabileze formulation resulted in stand establishment similar to that in the autoclaved soil. Mycofumigation was ineffective in controlling Fusarium wilt of sugar beet. Neither M. albus nor M. roseus affected sugar beet or eggplant growth or appearance except in the stabileze formulation, where stunting was noticed. Mycofumigation with M. albus and M. roseus shows promise for control of soilborne diseases caused by P. ultimum, A. cochlioides, R. solani, and V. dahliae.

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