ETIOLOGY OF FUNGI ASSOCIATED WITH GRAPEVINE DECLINE AND THEIR PATHOLOGICAL POTENTIAL

Abstract

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 solaniKuhn 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.

Keywords

• grapevine
• root-rot
• etiology
• pathological potential
• fusarium spp
• botryodiplodia theobromae
• rhizoctonia solani