Factors affecting lettuce damping-off and root rot diseases incidence [electronic resource].

Includes references.

Soil borne pathogens have been reported to attack lettuce at different development stages. Rhizoctonia solani was the most frequently' isolated fungus from El-Sharkia, EI-Ismailia and El-Kaliobia governorates during 1999 and 2000 growing seasons, followed by Fusarium oxysporum and Sclerotinia sp. While, Aspergillus sp. and Penicillium sp. were the lowest frequently isolated fungi. F. oxysporum, Sclerotinia sp. and R. solani, respectively, behaved the highest percentage of damping-off and root rot diseases incidence. However, Aspergillus sp. and Penicillium sp. were not effective in this respect.' Balady lettuce cultivar proved to be most susceptible to infection by the tested fungi rather Romain cv. Cultivation in clay soil type reveal the highest percentage of healthy survival Balady lettuce plants with no significant differences with those cultivars grown in infested Sandy loam soil. The incidence of damping-off and root rot of lettuce were reduced when NPK at level N3P3K3, + bran as an organic matter, was used. Irrigating infested soil using 25% raw sewage resulted in the highest percentage of healthy survival plants. The bioagent Trichoderma viride was more effective biocontrol agent tested under laboratory conditions than T. harzianum. Adding the biocontrol agents tested before cultivation reduced th percentage of damping-off and root rot of lettuce plants cultivated ininfested soil with the three tested pathogenic fungi. Vitavax-300 proved to be the best fungicide in controlling lettuce diseases incidence when applied as treatment for lettuce seedlings soaking.

Summary in Arabic.

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