Thesis (M.Sc.) - Cairo University - Faculty of Agriculture - Department of Plant Pathology and Physiology

Isolation trials carried out from samples of cantaloupe plants suffering from vine decline and root rot collected from Giza (El- Ayaat), Beni Suef (Seds), Behera (Wadi El Natrown) and Matruh (Alhamam) governorates yielded 6 different fungal genera. These fungi were identified as Sclerotium bataticola, Rhizoctonia solani, Botryodiplodia sp., Plectosphaerella melonis, Monosporascus cannonballus , Fusarium solani and Fusarium oxysporum. Pa. melonis, as a new first report in Egypt was only isolated from Behera (Wadi El Natrown). The most frequent isolated pathogen from rotted rot and vine decline of cantaloupe plants was Pa. melonis. Meanwhile, the lowest percentage of frequency was recorded for F. oxysporum.The pathogenicity of the isolated fungi in pot experiments revealed that the great percentage of cantaloupe root rot was recorded from soil infested with F. solani even after one or two months post transplants. In microplots experiment using different double combinations of the fungi tested the highest average percentage of cantaloupe root rot and disease severity index were obtained from soil artificially infested with all the tested fungi. The effect of five different degrees of temperature on the linear growth of the fungi tested was carried out in vitro. It was found that any of the fungi tested were not able to grow 10{u00B0}C. Whereas, start of growth of all the fungi occurred when the fungi incubated at 15 {u00BA}C but the growth of M. cannonballus started late (96hrs) from incubation at this degree. Studying the effect of different degrees of temperatures on the growth dry weight (mg) of the tested fungi after 5,10 and 15 days of incubation indicated that the dry weight of the fungi was increased by the increase in the temperature degrees tested

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