scholarly journals The biological control of seed-borne Alternaria brassicicola of cruciferous plants with a powdery preparation of Streptomyces sp.

1987 ◽  
Vol 59 (3) ◽  
pp. 199-208 ◽  
Author(s):  
Risto Tahvonen ◽  
Hanna Avikainen
Keyword(s):  
Biological Control ◽  
Brassica Species ◽  
Fine Sand ◽  
Alternaria Brassicicola ◽  
Damping Off ◽  
Streptomyces Sp ◽  
Seed Dressing ◽  
Dry Conditions ◽  
Cruciferous Plants ◽  
Different Origin

The effectiveness of a powdery preparation of a Streptomyces sp. isolate as a seed dressing agent against seed-borne Alternaria brassicicola on different Brassica species was investigated in the study. The preparation was made by freeze-drying and milling the biomass produced in a fermentor into a form suitable for use as a dusting agent. Seed dressing was 80—90 % successful in controlling damping-off from seeds artificially infected with A. brassicicola. The effectiveness of dressing remained unchanged on seeds stored under dry conditions for 5—6 weeks, but subsequently decreased slowly and was ca. 50 % six months after dusting. Streptomyces dressing controlled, in a manner comparable to chemical dressing with thiram, damping-off caused by Alternaria fungi on seedlings which were grown from commercial seed lots of different origin. The results of biological control of damping-off did not vary in the peat lots of different origin whose natural disease suppressivity varied considerably. The control result was the same or better than chemical dressing with thiram. The acidity of the substrate (pH 4.8—8.6) had no effect on the effectiveness of biological control. The results obtained against Alternaria damping-off were the same in other substrates clay, fine sand and mull as in peat.

scholarly journals Preliminary experiments into the use of Streptomyces spp. isolated from peat in the biological control of soil and seed-borne diseases in peat culture 

1982 ◽  
Vol 54 (5) ◽  
pp. 357-369 ◽  
Author(s):  
Risto Tahvonen
Keyword(s):  
Biological Control ◽  
Sugar Beet ◽  
Fusarium Culmorum ◽  
Fine Sand ◽  
Alternaria Brassicicola ◽  
Foot Rot ◽  
Damping Off ◽  
Sand Soil ◽  
Seeding Layer ◽  
Streptomyces Spp

Streptomyces spp. isolates obtained from peat effectively inhibited the growth of Alternaria brassicicola Wiltshire, Fusarium culmorum (W. G. Smith) Sacc., F. sulphureum Schlechtendahl, Pythium debaryanum auct. non Hesse and Rhizoctonia solani Kühn on PDA medium, but Streptomyces spp. isolates from fine sand soil were not effective against F. culmorum compared to the strains isolated from peat. Treatment of cauliflower seeds with Streptomyces spp. isolated from peat effectively controlled damping-off caused by A. brassicicola and R. solani when the seedlings were grown on either disinfected or fresh peat. Spraying the seeding layer of the peat substrate with a suspension of Streptomyces reduced the mortality of barley sprouts and foot rot caused by F. culmorum, and damping-off on sugar beet caused by P. debaryanum.

scholarly journals Seed-borne fungi on cruciferous cultivated plants in Finland and their importance in seedling raising

1979 ◽  
Vol 51 (1) ◽  
pp. 327-379
Author(s):  
Risto Tahvonen
Keyword(s):  
Alternaria Brassicicola ◽  
Cultivated Plants ◽  
Damping Off ◽  
Turnip Rape ◽  
Red Cabbage ◽  
White Cabbage ◽  
Cabbage Seed ◽  
Lower Temperature ◽  
Whetzelinia Sclerotiorum ◽  
Cruciferous Plants

The seed-borne fungi of cabbage, swede, turnip, rape, turnip rape, radish and black radish and their importance in seedling raising have been examined in this study. The seed lots used in the study were on sale at seed merchants in Finland during the period 1968 —1976. Alternaria brassicicola (Schw.) Wiltshire was the most common pathogen, being more common on cabbage than on any of the other plant species. 91 % of the white cabbage and red cabbage seed lots were infected. The mean A. brassicicola contents of the infected seed lots were 29.5 % and 30.6 %. Plenodomus lingam (Tode ex Fr.) Höhnel occurred in 10 % of the white cabbage and 27 % of the red cabbage seed lots, the fungus content varying from 0.5 % to 14 %. The fungus was also found on cauliflower, swede and radish. Alternaria brassicae (Berk.) Sacc. was found in 4 % of the cabbage and in 31 % of the rape seed lots at fungus contents of 0.5—6.5 %. Alternaria raphani Groves & Skolko was found in 30 % of the radish and black radish seed lots at fungus contents of 0.5—8 %. The following fungi were also found on the seeds of Cruciferous plants: Pleospora herbarum (Pers.) Rabenh., Whetzelinia sclerotiorum (Lib) Korf & Dumont, Botrytis cinerea Pers., Ulocladium concortiale (Thum.) Simmons, Fusarium spp. and Rhizoctonia solani Kühn as well as 18 fungus genera and species either saprophytic or pathogenic to other plants. When the Alternaria brassicicola content of the seeds was 20 % it caused 10 % damping-off damage on the sand substrate. A similar level of damage occurred on the peat substrate when the fungus content reached 70 %. In addition to causing damping off and damaging the seedlings, the fungus also slowed-down seedling growth without apparently damaging them. When the seedlings were grown at a lower temperature the amount of damage caused by A. brassicicola was much less than that which occurred when a higher temperature was used. Plenodomus lingam caused as much damping-off as there were seeds infected with the fungi. Other seed-borne fungi had no importance in seedling raising. Sphagnum fuscum peat, which is used in Finland as a growth substrate, reduced the amount of damping-off caused by seed-borne fungi in comparison to disinfected substrates and prevented the spread of A. brassicicola and P. lingam from diseased to healthy seeds. Dressing the seeds with thiram proved to be very effective against A. brassicicola.

scholarly journals Biological Control of Pythium Damping –off in Seedlings with Streptomyces Sp.

2019 ◽  
Vol 8 (4) ◽  
pp. 8035-8039
Keyword(s):  
Biological Control ◽  
Antifungal Activity ◽  
Research Work ◽  
Pythium Aphanidermatum ◽  
Dual Culture ◽  
Damping Off ◽  
Zone Of Inhibition ◽  
Streptomyces Sp ◽  
Rdna Sequencing ◽  
Forest Nurseries

Damping-off is one of the severe diseases caused by soil-borne pathogens notably Pythium sp. the causative agent of this infection in raising tree saplings in forest nurseries. Biological control is an eco-friendly approach in disease management compared to chemical fungicides which in turn affects the soil environment. Biocontrol of Pythium sp. has been emphasized in vegetable nurseries than forest nurseries. The present research work is focused on identification of effective antagonistic organism from forest nursery soils against Pythium aphanidermatum. Bacteria were isolated from various forest soils collected from Boluvampati, Sirumugai and Mettupalayam forest nurseries in Coimbatore district and soil samples were screened for antifungal activity against Pythium aphanidermatum by dual culture technique. Among 245 bacterial isolates, one isolate KUMB1.1 exhibited clear zone of inhibition of 1cm and it was identified by 16S rDNA sequencing as Streptomyces sp. Solvent extraction was performed to isolate an active compound using ethyl acetate, dichloromethane, n-butanol, hexane and chloroform in the ratio 1:1. The antifungal activity of compound was performed by well plate method against Pythium sp. and nbutanol extract exhibited zone of inhibition. The antifungal activity of Streptomyces sp. was tested in a model plant Solanum lycopersicum (Tomato) seeds raised in Pythium aphanidermatum infested soils in seed trays under in vitro conditions. Preemergence and post-emergence disease incidences were observed, and the results exhibited promising efficacy of Streptomyces sp. against the fungal pathogen Pythium aphanidermatum. Seedbed study was carried out in Gmelina arborea seeds, where the seeds are treated with Streptomyces culture broth. In which seed treatment shows 43% increase in germination compared with control.

Biological Control of Tomato Seedling Damping off with Streptomyces sp.

2005 ◽  
Vol 4 (2) ◽  
pp. 91-95 ◽  
Author(s):  
D. Dhanasekar ◽  
P. Sivamani ◽  
A. Panneersel ◽  
N. Thajuddin ◽  
G. Rajakumar ◽  
...  
Keyword(s):  
Biological Control ◽  
Damping Off ◽  
Tomato Seedling ◽  
Streptomyces Sp

The pathogenicity of an Australian isolate of Acremonium zonatum to water hyacinth, and its relationship with the biological control agent, Neochetina eichhorniae

1987 ◽  
Vol 38 (1) ◽  
pp. 219 ◽  
Author(s):  
JC Galbraith
Keyword(s):  
Biological Control ◽  
Water Hyacinth ◽  
Biological Control Agent ◽  
Control Agent ◽  
Control Programme ◽  
Australian Isolate ◽  
Free Moisture ◽  
Neochetina Eichhorniae ◽  
Dry Conditions ◽  
The Individual

The first description of Acremonium zonatum on water hyacinth in Australia is made. Its pathogenicity was studied as part of the search for a microorganism already present in Australia which could be developed as a mychoherbicide to supplement the arthropod biological control programme in this country. Following inoculation with A. zonatum, extensive leaf infections developed, favoured by injury and free moisture, but new leaves continued to form. Feeding by the weevil, Neochetina eichhorniae, increased infection by A. zonatum in relatively dry conditions, but it is unlikely that this was due to feeding scars acting as ports of entry. A. zonatum spores were transported on the feet and in the digestive tract of the weevil. The growth of infected plants, estimated by standing crop, was reduced by 49% compared to the control. A further decrease occurred in infected plants infested by weevils, but the total reduction in growth was not equal to the sum of the individual effects of fungus and weevil. Infection did not develop in 15 other plant species inoculated with the Australian isolate of A. zonatum. Although not a virulent pathogen, A. zonatum has some favourable characteristics for consideration as a mycoherbicide and has not appeared antagonistic to N. eichhorniae in these studies. Its role probably lies in exerting a chronic stress on plants already under attack by arthropod biological control agents.

scholarly journals Streptomyces sp.: Characterization, Identification and Its Potential as a Ralstonia solanacearum Biological Control Agent in vitro

2019 ◽  
Vol 2 (3) ◽  
pp. 89-96 ◽  
Author(s):  
Rachmad Saputra ◽  
Triwidodo Arwiyanto ◽  
Arif Wibowo
Keyword(s):  
Biological Control ◽  
Bacterial Wilt ◽  
Ralstonia Solanacearum ◽  
Biological Control Agent ◽  
Wilt Disease ◽  
Molecular Characteristics ◽  
Streptomyces Sp ◽  
Bacterial Wilt Disease ◽  
Wide Range

Streptomyces sp. bacteria have the potential to produce antibiotic compounds, which are one of the mechanisms that are widely used in biological control. However, in general, biological control mechanisms also occur through competition, cell wall degradation and induced resistance. This study was aimed to determine the physiological, biochemical and molecular characteristics of two isolates of Streptomyces sp. (S-4 and S16 isolates) isolated from the tomatoes roots, and to find out their ability to control Ralstonia solanacearum, which causes bacterial wilt disease on a wide range of hosts. The results showed both Streptomyces sp. isolates had several different physiological and biochemical characteristics and had a different ability to inhibit R. solanacearum in vitro. Streptomyces sp. S-16 isolate had a high similarity with Streptomyces diastaticus subsp. ardesiacus strain NRRL B-1773T based on the molecular identification results. Further research needs to be done to see the potential inhibition of the two Streptomyces isolates in inhibiting the development of bacterial wilt disease in tomato plants caused by R. solanacearum.

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