الفهرس | Only 14 pages are availabe for public view |
Abstract Fennel (Foeniculum vulgare L) is considered as one of the most important medicinal plants in the world. Fennel is attacked by many fungal diseases cause considerable losses for producers. Soil borne pathogens are considered as a major factor cause reduction in fennel yield. Biological control, when properly implemented, is usually more effective, durable and less in cost. Different biocontrol agents belong to fungi, actinomycetes and bacteria were used to evaluate their effects on controlling these pathogens. The present work was designed to control pathogenic soil borne fungi attack fennel using Trichoderma harzianum, Bacillus subtilis ,Streptomyces griseus(A1), S. tendae (A2) and S. canescens (A3) isolates. Results show that all treatments led to clear significant reduction in root rot disease incidence compared with control treatment. Suitable date for adding different antagonistic microorganisms were also studied , data obtained show that adding any of used treatment before planting time was more effective than adding the same treatment at planting or one or two weeks after planting. Using different isolates of antagonists at different concentrations, as seed coating, show positive correlation between increase antagonists concentrations and efficacy of the treatment. Adding antagonists as soil drench were better than adding the same antagonists as seed coating.In field experiments the highest yield was obtained when S. griseus (A1) was added before planting time as soil drench. Root protection in fennel plants against root rot pathogen was reflected on plant in form of increase, number of inflorescences, weight of 100 seeds and total yield. Also, it was found that adding S.griseus (A1) to fennel seeds as powder or soil drench led to increase percentage of oil in fennel seeds and led to increase in weight of 100 seeds. Organic agriculture provides substitutes for all toxic fungicides are used in conventional agriculture. Biological control agents are allowed according to European laws (EC 834 / 2007). We can suggest that production of T. harzianum, B. subtilis ,S.griseus(A1), S. tendae (A2) and S. canescens (A3) isolates on commercial scale to be used to control fennel root rots disease under field conditions in organic farms. Key words: Fennel, Root rot, Biological control, Streptomyces spp. , Trichoderma harzianum, Bacillus subtilis , Fennel oil |