Role of Combination among Bioagents, Compost and Soil Solarization on the Management of Some Root Infecting Fungi Responsible for Crown and Root-Rot Diseases of Strawberry

The antagonistic bacteria, i.e. B. megaterium , B. pumilus , B. subtilis, Pseudomonas fluorescens and P. putida isolated from the rhizospheric soil of strawberry plants were screened for their efficacy against the pathogenic fungi ,i.e. Fusarium solani , Macrophomina phaseolina and Rhizoctonia solani, responsible for causing crown and root-rot diseases of strawberry, in vitro and in vivo. In general, P. fluorescens followed by megaterium were the most efficient ones in reducing the linear growth of the tested three pathogenic fungi than the other isolates.

Sterilized filtrate of the tested compost (compost tea) resulted in significant reduction to the linear growth of the tested three fungi compared with the control treatment. This reduction was gradually increased by increasing it׳s concentration.

The Average of the soil temperature at depths of 15 and 25 cm. was 59.7 and 51.3 ˚C during the period of soil solarization. The pathogenic three fungi failed to re-isolate from the infected segments of solarized roots for 40 days at 15 and 25 cm. depths. In addition, low frequency was recorded in case solarized crown segments, especially at 25 depths.

Plot experiment revealed that the tested bioagents , i.e. B. megaterium and P. putida , compost and soil solarization, each alone or in different combination, caused significant reduction to the infection by the mixed inoculums of the three causal fungi (dead plants and root-rot severity) with significant increase to the produced fruit yield and their total soluble soils (TSS) compared with the control treatment. 

Keywords: Strawberry, bacterial bioagents , compost , crown and root-rot , fruit yield , management , soil solarization, total soluble solids (TSS).