NOVELTY - Use of agent containing microbial inoculum comprising Trichoderma reesei (ACCC 30150) and Streptomyces silaceus (ACCC 40021) as active components, is claimed in preparation of organic fertilizer for promoting growth and/or controlling diseases in tobacco.    USE - The microbial inoculum containing agent is useful in seedling culturing matrix and preparation of organic fertilizer for promoting growth preferably growth of seedlings, seedlings root, stem and leaves and/or controlling diseases preferably bacterial wilt diseases, brown and black shank diseases in tobacco (all claimed).    ADVANTAGE - The microbial inoculum improves weight of tobacco leaves and roots and germination rate of tobacco seedling and hence production of tobacco is also improved. The inoculum shortens seedling germination period and time period to attain maximum yield, raises or promotes tobacco cultivation and increases length and width of tobacco leaves. The microbial inoculum improves root surface area of tobacco, average diameter of tobacco root, total root length, stem grith, number of leaf blades and width of leaves, and increases root volume of tobacco seedlings. The microbial inoculum is environmentally-friendly, cost-effective, safe for tobacco crops as the inoculum contains antagonistic microorganisms and hence is favorable for popularization and usage in organic fertilizer and organic fertilizer-based agriculture, and inhibits development of resistance in disease causing pathogens. The microbial inoculum effectively controls bacterial and fungal diseases as presence of antagonistic microorganisms in soil enables biological control of pathogenic bacteria and fungi in the soil, effectively improves soil environment, maintains or balances agroecological system, and lays foundation for sustainable development of tobacco.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) the above-mentioned microbial inoculum; and    (2) organic fertilizer comprising the above-mentioned microbial inoculum.