CONTROL OF STRAWBERRY SOIL-BORNE PATHOGENS IN SOIL LIKE SUBSTRATE OF RECYCLED RICE STRAW

Rice straw decomposition was done within 45-60 days with 6 different biological and chemical methods using Trichoderma harzianum, T. album, ruminant fluid microflora from large animal s stomach, 3 different species of decomposition bacteria; chicken manure water extract and chemical fertilizers. Two strawberry cultivars (Festival and Susana) highly susceptible to crown rot, root rot, wilt and anthracnose diseases were used and its fresh seedlings were cultivated in decomposed rice straw and naturally infested soil in two locations at Ismailia and El-Behera governorates. Data recorded 120 days after sowing showed clear reduction of infected plants with soilborne pathogens grown in decomposed rice straw bags to 0.7 and 1.6% while it increased to 8.5 and 76.6 % for plants grown in natural soil treated with methyl bromide in El-Behera and Ismailia, respectively. Strawberry plants grown on rice straw bags showed better growth and an increase in strawberry fruits of good quality and quantity as compared with the control plots under natural soil conditions. The pH around the roots in decomposed rice straw bags ranged from 5.5 to 6.5, slightly acidic, while it ranged from 7.5 to 8.5 (alkaline) around root system in natural soil. Infected plants with different symptoms of crown rots and black root rots yielded several fungi and fungus like organisms identified as Phytophthora cactorum, Colletotrichum acutatum, Rhizoctonia solani, Scelerotium bataticola, Fusarium oxysporum, F. solani and Pythium ultimum. Based on the above result, it could be recommended that using decomposed rice straw bags as a growing substrate that improve the production and quality of strawberry under open field conditions in Egypt. This method provided new options for farmers wishing to be more environment friendly and add new economic value to rice straw waste as cheaper substrate compared with commercial grow-bags.