Fecha de publicación: 30/04/2014 Fuente: WIPO "tobacco agriculture" The invention provides an alternaria alternata inoculating liquid and a preparation method thereof. The preparation method comprises the following steps: culturing the alternaria alternata on a PDA (Potato Dextrose Agar) panel for 6-7 days at 28 DEG C; preparing a 1*10cfu/ml spore suspension liquid by a 0.5-1.5% (v/v) glucose liquid and 0.5-1.5% (v/v) tween-20 to obtain the alternaria alternata inoculating liquid. The alternaria alternata inoculating liquid provided by the invention is directly sprayed in the field to inoculate so as to effectively improve the morbidity of tobacco strains. In addition, the preparation method provided by the invention is simple and practical and easy to operate and popularize.6>