scholarly journals Selection of Microorganisms for Biological Control of Silver Scurf (Helminthosporium solani) of Potato Tubers

Plant Disease ◽  
1997 ◽  
Vol 81 (6) ◽  
pp. 647-652 ◽  
Author(s):  
M. K. Elson ◽  
D. A. Schisler ◽  
R. J. Bothast
Keyword(s):  
Biological Control ◽  
Xanthomonas Campestris ◽  
Physiological Age ◽  
Postharvest Disease ◽  
Silver Scurf ◽  
Infested Soil ◽  
Helminthosporium Solani ◽  
Biological Control Agents ◽  
Γ Irradiation ◽  
Selection Of

Few management strategies exist for silver scurf, an important postharvest disease of potatoes. In this study, the microbiota of 47 agricultural soils and 7 tuber samples was screened for biological control agents of silver scurf. Soil or periderm samples were transferred to separate samples of γ irradiation-sterilized field soil enriched with potato periderm. After incubation, the samples were assayed for biological suppressiveness to silver scurf using a whole-tuber/infested soil assay. Over 430 isolates of bacteria, yeasts, and actinomycetes were recovered from tubers and soil associated with the 12 most suppressive soil samples. Thirteen strains were selected for further study on three different strains of Helminthosporium solani, including one that was resistant to thiabendazole. Microbial strains that significantly inhibited H. solani (P ≤ 0.05) in at least one experiment were identified as Pseudomonas putida (PM1), Nocardia globerula (S244), and Xanthomonas campestris (P76). Colonization studies with rifampicin-resistant strains of putative biological control agents revealed that long-term colonization of the tuber surface was not necessary to reduce disease symptoms. Highly variable levels of conidiophore production prevented selection of the single most suppressive strain. Possible sources of variability in biological control are discussed, including physiological age of the tuber, tuber infection in the field, and uneven free moisture in the storage.

scholarly journals Reduction of Landscape Pathogens in Florida by Soil Solarization

Plant Disease ◽  
2002 ◽  
Vol 86 (12) ◽  
pp. 1388-1395 ◽  
Author(s):  
R. J. McGovern ◽  
R. McSorley ◽  
M. L. Bell
Keyword(s):  
Biological Control ◽  
Crown Rot ◽  
Soil Solarization ◽  
Shoot Biomass ◽  
Infested Soil ◽  
Pseudomonas Chlororaphis ◽  
Biological Control Agents ◽  
Central Florida ◽  
Air Space ◽  
Polyethylene Mulch

Two experiments were conducted during autumn 1997 and 1998 in west-central Florida to evaluate the effectiveness of soil solarization alone and in combination with the biological control agents Streptomyces lydicus (Actinovate) and Pseudomonas chlororaphis (syn. P. aureofasciens, AtEze) and the reduced-risk fungicide fludioxonil (Medallion) in managing soilborne pathogens of impatiens (Impatiens × wallerana, ‘Accent Burgundy’). Naturally infested soil was solarized for 47 or 48 days during September and October using two layers of 25-μm clear, low-density polyethylene mulch, separated by an air space of up to 7.5 cm. Solarization decreased the final incidence and progress of Rhizoctonia crown rot and blight, incidence of Pythium spp. in roots, and root discoloration, and increased shoot biomass in both experiments. The technique also consistently reduced root-knot severity and population densities of Meloidogyne incognita, Dolichodorus heterocephalus, Paratrichodorus minor, and Criconemella spp. The incidence of Rhizoctonia crown rot and blight was reduced by fludioxonil, but not by the biological control agents.

Cultivable microbiota of Lithobates catesbeianus and advances in the selection of lactic acid bacteria as biological control agents in raniculture

2012 ◽  
Vol 93 (3) ◽  
pp. 1160-1167 ◽  
Author(s):  
Gabriela Montel Mendoza ◽  
Sergio E. Pasteris ◽  
Cesar E. Ale ◽  
María C. Otero ◽  
Marta I. Bühler ◽  
...  
Keyword(s):  
Biological Control ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Biological Control Agents ◽  
Lithobates Catesbeianus ◽  
Selection Of

Biological Control of Bacterial Blight of Geranium with H-Mutant Bacteriophages

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 519c-519 ◽  
Author(s):  
Brent K. Harbaugh ◽  
Jeffrey B. Jones ◽  
Lee E. Jackson ◽  
Gail Somodi ◽  
Joseph E. Flaherty
Keyword(s):  
Biological Control ◽  
Bacterial Blight ◽  
Xanthomonas Campestris ◽  
Wild Type ◽  
Novel Approach ◽  
Bacterial Mutants ◽  
Spraying Plants ◽  
Serious Disease ◽  
Wild Type Parent ◽  
Selection Of

Bacterial blight, caused by Xanthomonas campestris pv. pelargonii (XCP), is considered the most serious disease of geraniums (Pelargonium × hortorum). A novel approach that uses bacteriophages (phages, viruses that kill bacteria) for the biological control of geranium blight will be presented. Phages were once abandoned as biological control agents due to the emergence of bacterial mutants resistant to the phages employed. However, our approach utilizes a mixture of three to eight different phages including host-range mutants (H-mutants). H-mutants are spontaneously derived from their wild-type parent phages and lyse not only parent wild-type bacteria, but also phage-resistant mutants originating from parent bacteria. Two phages specific for XCP initially were isolated from soil samples from Florida and California. These phages produced virulent reactions in six of 30 XCP strains, and lysogenic reactions in 22 strains. After selection of these phages for increased virulence and additional phages were isolated from MN and UT, 17 phages were evaluated for sensitivity to 21 XCP strains from around the world. Four to 14 phages produced virulent reactions in the 21 XCP strains. Five phages produced virulent reactions in at least 17 XCP strains. A mixture of five phages tested against the 21 XCP strains produced virulent reactions for all 21 XCP strains. Geraniums in 10-cm pots were inoculated with XCP and placed on a greenhouse bench in the middle of 5 non-inoculated plants. After 2 weeks of daily spraying plants with a phage solution (109 pfu phage/ml) or water, there was a 71% reduction in the number of bacterial lesions on phage-treated plants.

scholarly journals Effect of Organic and Inorganic Salts on the Development of Helminthosporium solani, the Causal Agent of Potato Silver Scurf

Plant Disease ◽  
2002 ◽  
Vol 86 (9) ◽  
pp. 1014-1018 ◽  
Author(s):  
V. Hervieux ◽  
E. S. Yaganza ◽  
J. Arul ◽  
R. J. Tweddell
Keyword(s):  
Calcium Chloride ◽  
Control Strategies ◽  
Sodium Formate ◽  
Postharvest Disease ◽  
Potassium Sorbate ◽  
Sodium Metabisulfite ◽  
Silver Scurf ◽  
Helminthosporium Solani ◽  
Economic Significance

Potato silver scurf, caused by Helminthosporium solani, is an important postharvest disease of economic significance. Control of H. solani has been accomplished primarily by postharvest applications of thiabendazole. However, many strains of H. solani have become resistant to thiabendazole, resulting in failure of disease control. Consequently, alternative control strategies are needed. This study showed that several salts significantly reduced silver scurf development on potato tuber at a concentration of 0.2 M and that the timing of application also influenced salt efficacy. Among the 23 tested salts, aluminum chloride was the only one reducing silver scurf severity when applied either 2, 4, or 7 days after H. solani inoculation. Aluminum lactate, potassium sorbate, sodium carbonate, sodium metabisulfite, and trisodium phosphate also markedly reduced silver scurf severity but only when applied 2 or 4 days after inoculation. Ammonium acetate, calcium chloride, sodium benzoate, sodium citrate, and sodium formate reduced disease severity by at least 50% when applied 2 days after H. solani inoculation. With the exception of calcium chloride and sodium formate, these salts also were shown to strongly inhibit H. solani mycelial growth or spore germination in vitro. Results of this study further demonstrate the possibility of using selected salts for the control of potato silver scurf.

scholarly journals New Antimicrobial Phenyl Alkenoic Acids Isolated from an Oil Palm Rhizosphere-Associated Actinomycete, Streptomyces palmae CMU-AB204T

2020 ◽  
Vol 8 (3) ◽  
pp. 350 ◽  
Author(s):  
Kanaporn Sujarit ◽  
Mihoko Mori ◽  
Kazuyuki Dobashi ◽  
Kazuro Shiomi ◽  
Wasu Pathom-aree ◽  
...  
Keyword(s):  
Biological Control ◽  
Antibacterial Activity ◽  
Antifungal Activity ◽  
Oil Palm ◽  
Xanthomonas Campestris ◽  
Antimicrobial Agents ◽  
Antimicrobial Activities ◽  
Culture Broth ◽  
Spectroscopic Techniques ◽  
Biological Control Agents

Basal stem rot (BSR), or Ganoderma rot disease, is the most serious disease associated with the oil palm plant of Southeast Asian countries. A basidiomycetous fungus, Ganoderma boninense, is the causative microbe of this disease. To control BSR in oil palm plantations, biological control agents are gaining attention as a major alternative to chemical fungicides. In the course of searching for effective actinomycetes as potential biological control agents for BSR, Streptomyces palmae CMU-AB204T was isolated from oil palm rhizosphere soil collected on the campus of Chiang Mai University. The culture broth of this strain showed significant antimicrobial activities against several bacteria and phytopathogenic fungi including G. boninense. Antifungal and antibacterial compounds were isolated by antimicrobial activity-guided purification using chromatographic methods. Their structures were elucidated by spectroscopic techniques, including Nuclear Magnetic Resonance (NMR), Mass Spectrometry (MS), Ultraviolet (UV), and Infrared (IR) analyses. The current study isolated new phenyl alkenoic acids 1–6 and three known compounds, anguinomycin A (7), leptomycin A (8), and actinopyrone A (9) as antimicrobial agents. Compounds 1 and 2 displayed broad antifungal activity, though they did not show antibacterial activity. Compounds 3 and 4 revealed a strong antibacterial activity against both Gram-positive and Gram-negative bacteria including the phytopathogenic strain Xanthomonas campestris pv. oryzae. Compounds 7–9 displayed antifungal activity against Ganoderma. Thus, the antifungal compounds obtained in this study may play a role in protecting oil palm plants from Ganoderma infection with the strain S. palmae CMU-AB204T.

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