Effect of Combination among Bioagents, Compost and Soil Solarization on Management of Strawberry Fusarium Wilt

Abstract

Isolation trials from strawberry plants showing mainly wilt symptoms grown at Behera, Ismailia, Kalubia and Giza governorates yielded Fusarium oxysporum , F.solani , Macrophomina phaseolina , Pythium ultimum , Phytophthora cactorum , Rhizoctonia solani and Sclerotium rolfsii . Pathogenicity test of the four isolates of F.oxysporum revealed that they caused wilt symptoms and Kalubia isolate was the most virulent one. In addition, inoculating different seven plants, i.e. bean, cucumber, eggplant, sweet pepper, strawberry, tomato and water melon with F. oxysporum isolate of Kalubia governorate indicated that it caused wilt symptoms to strawberry plants only. Therefore, it named Fusarium oxysporum f.sp. fragariae Winks & Y.N. Williams. Four isolates of Bacillus spp., i.e. Bacillus coagulans , B.humilus , B.subtils and B. thringiensis and one isolate of Pseudomonas flurescens were isolated from the rhizospheric soil of strawberry plants grown in a field have severe infection by Fusarium wilt were screened for their efficacy against F. o. f.sp. fragariae, in vitro and in vivo. In general, P.flurescens followed by Bacillus subtilis were the most efficient in reducing the linear growth of the pathogenic fungus. Sterilized aqueous filtrate of the tested compost resulted in significant reduction to the linear growth of the tested fungus compared with control treatment. This reduction was gradually increased by increasing it׳s concentration. The combination among the bioagents B.subtilis and P.flurescens, compost and soil solarization resulted in significant reduction to strawberry Fusarium wilt with significant increase to the produced fruits and their total soluble solids (T.S.S.) , either each of them was used alone or in their different combinations, compared with control treatment (infested with the causal fungus).On the other hand, compost was the most efficient in this regard compared with the other three items of disease management, i.e. soil solarization and the bioagents B.subtilis and P.flurescens when each of them was used alone. Moreover, no apparent infection was detected when the bioagents B.subtilis and P.flurescens ,compost and soil solarization were used together and produced fruit yield of T.S.S., to somewhat, similar to control treatment ( uninfested soil with the causal fungus).