Abstract: Identification of the pathogen causing mildew on cigar tobacco leaf, and screening of the safe and efficient anti-mildew agents are very important for the production of high-quality cigar tobacco leaves. At present, several pathogenic fungi causing mildew on cigar tobacco leaf have been reported. This study identified the pathogenic fungus causing mildew on cigar tobacco leaf sampling from the Ganzhuang Cigar Fermentation Center of Yunnan Aromatic Tobacco Co., Ltd. and explored the green control technologies. By methods of the culturable and Koch's rule, the mildew pathogen of cigar tobacco leaves sampled from the Ganzhuang Cigar Fermentation Center of Yunnan Aromatic Tobacco Co., Ltd. was identified as Aspergillus montevidensis. The optimum growth temperature for A. montevidensis AM01 was 28 ℃. This strain hardly grew below 4 ℃ or above 40 ℃. Growth of AM01 strain did not require much oxygen, because the growth occurred in the range of 1.5%-15% oxygen concentration. In 7%-36.5% moisture content of the tobacco leaf, the disease index of mildew caused by AM01 strain increased significantly with the increase of moisture content, and the most severe of mildew was recorded at 36.5% moisture content. The IC₅₀ values of natamycin, thymol and antimicrobial peptide on mycelial growth of AM01 strain were 4.66 mg/L, 15.72 mg/L and 42.77 mg/L, respectively. The mildew rates of tobacco leaves sprayed with "1000 mg/L antimicrobial peptide", "500 mg/L thymol+1000 mg/L antimicrobial peptide" or "1000 mg/L thymol+1000 mg/L antimicrobial peptide" decreased respectively by 75.55%, 77.55% or 79.55% after 28 days of fermentation. When fumigated the tobacco leaves with "1000 mg/L thymol", "500 mg/L thymol +1000 mg/L antimicrobial peptide", "1000 mg/L thymol +1000 mg/L natamycin" or "1000 mg/L thymol +1000 mg/L antimicrobial peptide, the mildew rates decreased respectively by 77.11%, 81.12%, 79.11% or 81.78% after 28 days of fermentation.