Center Regional Of Recherche Agronomique Of Sotuba

Bamako, France

Center Regional Of Recherche Agronomique Of Sotuba

Bamako, France
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Dagno K.,Plant Pathology Unit Gembloux Agro Bio Technology | Dagno K.,University of Liège | Dagno K.,Center Regional Of Recherche Agronomique Of Sotuba | Lahlali R.,Agriculture and Agri Food Canada | And 3 more authors.
Journal of Aquatic Plant Management | Year: 2012

We recovered 116 fungal isolates in 7 genera from waterhyacinth plants having pronounced blight symptoms collected in Mali. Isolation frequency of the genera was Curvularia (60.32%), Fusarium (42.92%), Alternaria (11.6%), Coniothyrium (11.6%), Phoma (3.48%), Stemphylium (3.48%), and Cadophora (1.16%). On the basis of in vivo pathogenicity tests in which the diseased leaf area percentage and disease severity were visually estimated using a disease severity index, three isolates, Fusarium sp. Mln799, Cadophora sp. Mln715, and Alternaria sp. Mlb684 caused severe disease. These were later identified as Gibberella sacchari Summerell & J.F. Leslie, Cadophora malorum (Kidd & Beaumont) W. Grams, and Alternaria sp. respectively. This is the first report to highlight C. malorum as a candidate biocontrol agent against waterhyacinth. Neither C. malorum Mln715 nor Alternaria sp. Mlb684 in host specificity tests showed any pathogenicity toward 17 crop plants of economic importance in Mali.


Dagno K.,University of Liège | Dagno K.,Center Regional Of Recherche Agronomique Of Sotuba | Lahlali R.,Agriculture and Agri Food Canada | Diourte M.,Center Regional Of Recherche Agronomique Of Sotuba | Jijakli H.M.,University of Liège
African Journal of Microbiology Research | Year: 2011

Cadophora malorum isolate Mln715 and Alternaria jacinthicola strain MUCL 53159 are under development as biocontrol agents against Water Hyacinth (Eichhornia crassipes) in Mali. Production of spores of these agents on locally available substrates (Water Hyacinth, powdered paddy rice chaff, wheat semolina) was assessed with a view to mass production. The C. malorum isolate sporulated best on Water Hyacinth (4.08 × 10 7 spores ml -1), followed by wheat (1.06 ×10 7 spores ml -1), whereas A. jacinthicola produced more spores on paddy rice chaff and wheat (0.24 x 10 7 spores ml -1). The severity of the damage caused by each pathogen was evaluated in the greenhouse and in the field. Under both greenhouse and field conditions, the biocontrol efficacy of the fungal isolates was improved with (unrefined) Carapa procera (L.) oil or (refined) palm oil, supplemented with soybean lecithin and Tween 20. When such a formulation was used, the incubation time was 4 to 5 days in the greenhouse and 7 to 9 days on the field, and the damage severity (DS) recorded 6 weeks after treatment varied from 87.02 to 93.13% in the greenhouse and from 59.11 to 63.00% in the field. For unformulated C. malorum and A. jacinthicola respectively, the incubation times were longer and the DS values were only 22.11 and 29.05% in the greenhouse and 12.05 and 15.15% on the field. Our results highlight good substrates for mass production of these mycoherbicides and demonstrate the ability of vegetable oil formulations to improve their efficacy. © 2011 Academic Journals.


Dagno K.,University of Liège | Dagno K.,Center Regional Of Recherche Agronomique Of Sotuba | Lahlali R.,Agriculture and Agri Food Canada | Diourte M.,Center Regional Of Recherche Agronomique Of Sotuba | Jijakli M.H.,University of Liège
Biotechnology, Agronomy and Society and Environment | Year: 2012

Recent trends in the implementation of bioherbicide use in the control of water hyacinth (Eichhornia crassipes [Martius] Solms Laubach) have depended primarily on several strategies. The use of bioherbicides has been stimulated as part of the search for alternatives to chemical control, as the use of these more environmentally-friendly formulations minimizes hazards resulting from herbicide residue to both human and animal health, and to the ecology. In addition, one of the major strategies in the concept of biological control is the attempt to incorporate biological weed control methods as a component of integrated weed management, in order to achieve satisfactory results while reducing herbicide application to a minimum. Several fungal pathogens with mycoherbicide potential (Sclerotinia sclerotiorum in Hyakill™ and Cercospora rodmanii, named ABG-5003) have been discovered on diseased water hyacinth plants, but none has become commercially available in the market. Biological, technological, and commercial constraints have hindered progress in this area. Many of these constraints are being addressed, but there is a critical need to better understand the biochemical and physiological data regarding the pathogenesis of these new bioherbicides. Oil emulsions are recognized as a way to increase both efficiency of application and efficacy of biocontrol agents.


Dagno K.,University of Liège | Dagno K.,Center Regional Of Recherche Agronomique Of Sotuba | Lahlali R.,Agriculture and Agri Food Canada | Diourte M.,Center Regional Of Recherche Agronomique Of Sotuba | Jijakli M.H.,University of Liège
Journal of Applied Microbiology | Year: 2011

Aims: To determine the effect of water activity (a w = 0·880-0·960) and temperature (15-35°C) on the percentage of viable conidia and mycelial growth of three biocontrol agents effective against water hyacinth in Mali: Alternaria sp. isolate Mlb684, Fusarium sacchari isolate Mln799 and Cadophora malorum isolate Mln715.Methods and Results: The fungi were grown in vitro on plates containing potato dextrose agar medium at different a w values (glycerol being added to adjust the a w). The percentage of viable conidia and radial growth rate decreased with decreasing water activity. Statistical analysis showed a significant effect of a w, temperature and the a w × temperature interaction on mycelial growth (P < 0·0001). Water activity emerged as the factor exerting the greatest influence. Differences were observed between the fungi tested, the C. malorum appearing more tolerant to low a w and the F. sacchari more tolerant to high temperature (35°C). Growth models predicting the combined effect of a w and temperature were developed and response surfaces generated, showing fairly good agreement with the experimental values.Conclusions: Our results confirm the previous finding that a w has a greater influence than temperature on fungal growth. Under most conditions, variation of environmental factors has a detrimental influence on the percentage of viable conidia and mycelial growth rate of fungal isolates.Significance and Impact of the Study: The developed models may contribute to predicting the best environmental conditions for use of these fungi as effective biocontrol agents against water hyacinth. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

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