NOVELTY - Biological agent comprises stock solution formed by fermenting animal manure and microbial fertilizer, where the stock solution and microbial fertilizer is in a weight ratio of 1:1-1:3.    USE - The agent is useful for controlling fragrant pear rot disease (all claimed).    ADVANTAGE - The agent exhibits synergistic effect, activates soil, improves soil hardening, reduces usage of chemical fertilizers, promotes plant's photosynthesis ability, increases plant immunity, yield and quality of fruits compared with common chemical fertilizer, decreases rot by 70%, and achieves rot curative rate of 85%.    DETAILED DESCRIPTION - Biological agent comprises stock solution formed by fermenting animal manure and microbial fertilizer, where the stock solution and microbial fertilizer is in a weight ratio of 1:1-1:3. The stock solution is prepared by taking animal manure, soaking manure by adding 2-3 times water for 15-30 hours, stirring the mixture mechanically in a stirring tank after removal of impurities for 25-40 minutes, acidifying the stirred mixture, naturally fermenting the acidified mixture for 20-30 hours, anaerobically fermenting the fermented mixture at 30-40 degrees C for 80-100 hours to obtain stock solution. The microbial fertilizer comprises 8-12 parts photosynthetic microbial agents, 22-30 parts microbicide, 20-50 parts trace elements, and 11-15 parts plant conditioner. The photosynthetic microbial agents is at least one chosen from Rhodopseudomonas palustris, R.viridis, R.sphaeroides, and Pseudomonas monteilii. The microbicides is at least one chosen from Bacillus subtilis, B.megaterium, and B.polymyxa. The trace element comprises 3-8 pts. wt. copper sulfate, 40-70 pts. wt. ferrous sulfate, 6-10 pts. wt. manganese sulfate, 20-40 pts. wt. zinc sulfate, 20-40 pts. wt. magnesium sulfate, 20-40 pts. wt. calcium fertilizer, 0-0.15 pt. wt. molybdenum fertilizer, and 20-40 pts. wt. boric acid. The plant conditioner comprises 1.2-1.4 pts. wt. amino acid, 1.2-1.5 pts. wt. fulvic acid, 0.003-0.005 pt. wt. indole acetic acid, 0.04-0.05 pt. wt. naphthylacetate, 0.02-0.03 pt. wt. gibberellin, 0.01-0.02 pt. wt. sodium nitrophenolate, 0.12-0.14 pt. wt. rare earth element, 0.004-0.005 pt. wt. molybdenum fertilizer, and 0.4-0.6 pt. wt. zeatin. INDEPENDENT CLAIMS are included for the following:    (1) method (M1) for preparing the agent; and    (2) method (M2) for controlling fragrant pear rot disease using the agent.