Decline of grapevine due to soil borne fungi was surveyed during 2013-2015 summer growing seasons at El-Fayoum, El-Gharbeia and El-Beheira governorates, Egypt, Syndromes of declined grapevine plants included growth retardant of shoot system and root-rot as well as decrease of grapevine fruit yield quality. Isolation trails from root of declined trees of different grapevine cultivars i.e., superior, flame seedless, King robi and crimson was carried out. The most soil borne fungi associated with root-rotted grapevine were Fusarium oxysporum Schlechtend, Fusarium solani (Mart.) Sacc, Botryodiplodia theobromae, Rhizoctonia solani Kuhn and Macrophomina phaseolina(Tassi) Gold. Fusarium spp. are the main fungal associated with different infection types of declined root of grapevine either a singly or in combination with B. theobromae or R. solani as second infection type and third infection type with B. theobromae + R. solani. Under soil artificially infested with 5% (w/w) of each fungal isolates inocula of fourteen isolates obtained were varied for causing wilt and root-rot symptoms of grapevine trees and reducing growth parameters plant height, root length, root size, fresh and dry weight of shoot and root than the control. Botrydiplodia theobromae isolate No. (7) was the most caused root-rot and disease severity of shoot and root of grapevine plant(100%) followed by Fusarium avenacum caused (87.5%) of root-rot and disease severity of shoot and root. Fouthermore, Fusarium avenacum isolate was the most fungal isolate in reducing growth parameters expect root length. This is first record that Fusarium avenacum as a causal organism causing root rot disease of grapevine in Egypt.

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Pathogenic soil borne fungi causing epidemic root rot disease on grapevine and high loss of plant growth and fruit yield. Fast detection of aggressive fungal isolates is the first tool for introduce selection effective a agent for management disease progress. In vitro two simple techniques based on stem cutting of grapevine i.e., mycelial growth and cell wall degrading enzymes activities were evaluated for screening of aggressive fungal isolates in comparsion with classical pathogenicity test. Fourteen isolates of fungi associated with root rot disease of grapevine plants i.e. Fusarium oxysporumi Schlechtend, Fusarium solani (Mart.) Sacc, Botryodiplodia theobromae, Rhizoctonia solani Kuhn and Macrophomina phaseolina (Tassi) Gold. were tested and pathological action on grapevine plant (Cv.crimson) under soil artificially infested by classical method with their mycelial growth,cell wall degrading enzymes activities on stem cutting of grapevine as well as each fungal isolates of shoot and root compare the control. Fungal isolate of Botryiodiplodia theobromae No. (7) was the most isolate recorded high and significant root rot (100%) incidence and disease severity on grapevine plants followed by Fusarium avenacum isolate No. (11) and Fusarium solani isolate No. (12). Positive correlation co-efficient was observed between mycelial growth of fungal isolates tested on stem cutting of grapevine plants and root rot disease incidence and their disease severity followed by their production pectinase and cellulase enzymes. So, mycelial of fungal growth on stem cutting of grapevine is a good and simple of opportunity technique for determination aggressive degrees of fungal isolates in vitro as alternative accuracy, very short time test and very shape cost than classical pathogenicity test.

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