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Titre : Studies on the Irradiated Trichoderma and Their Metabolites for Controlling Tomato Fungal Disease

Auteur : Ahmed, Shaimaa Mohamed Fahmy.

Etablissement de soutenance : Menoufiya University.

Grade : Doctor of Philosophy in Agricultural Science 2017

Résumé partiel
Tomato is an important commercial crop in the world. Sensory and nutritional characteristics make it a widely accepted vegetable by consumers. Tomato is grown in most countries of the world, being Asia the largest producer. The area devoted to tomato cultivation is estimated to be 3 million hectares in the world. The cultivated area of tomato in Egypt is progressing at a relative fast rate, especially in newly reclaimed desert lands. According to Economical Statistic Report, Agriculture Statistic, Economic Affairs Sector (Vegetable Crops), August, 2015, Ministry of Agriculture and Land Reclamation, ARE, cultivated area of tomato was 509562 fadden, yielded 8264543 tons, with average of 16.912 tons / fadden. Many fungal diseases attack Tomato plants during growing season and cause economic loss in cropping fruit yield as well as the large losses in field. The root rot diseases are very important and cause great loss in fruit yield. These trials were conducted to study the causal organisms of root rots and their control. Results can be concluded as follows : 1. Tomato plant showing typical root rot symptoms were collected from 6 governorates of Egypt (Beheira, Giza, Ismailiya, Qalubiya, Qena and Sharkiya). These samples were used for isolation of the causal organisms from diseased tomato plant materials. 2. Two hundred and fifty nine fungal pathogens were isolated from the diseased roots during 2012 and 2013 seasons. Data indicated that Alternaria solani was most frequent fungus was isolated from root of tomato plant but least frequent fungus was Paecilomyces spp. 3. Twenty fungal isolates out of 259 were tested for their virulence using tomato roots of (GF12/ the most susceptible tomato cultivar) were used in Pathogenicity test. Data indicate that all tested isolates were pathogenic to tomato roots under greenhouse conditions. Significant differences were noticed between unwounded and wounded roots. The most aggressive isolate was Alternaria solani isolate 1 followed by Rhizoctonia solani followed by Fusarium oxysporium isolate 1, whereas the lowest percentage of infection was obtained by Camarosporum tassi and R. oryzae. 4. Twenty bioagents belong to Trichoderma spp ; T. hamatum (5 strains), T. harzianum (5 strains), two strains from each of T. atroviride, T. longbactrium, T. reesei and T. viride and one strain from each of T. koningii and T. virens were isolated from soil and rhizosphere samples were taken selected from tomato fields by uprooting the infected plants. 5. The best control was recorded by T. harzianum Tz1, T. koningii Tk1, T. longbactrium Tl1 and T. viride Td1 are selected as the most potent bioagents that controlled the aggressive pathogens causing tomato root rot disease under laboratory and greenhouse conditions.

Présentation étendue (EULC)