Abstract: Nimbya alternantherae SF-193 is a strong phytopathogenic fungus causing foliar and stem necrosis of Alternanthera philoxeroides.However,the growth character and the security of the fungus are still unclear.Tests on its cultural and nutritional requirements showed that the optimum temperature for the growth was about 30℃,the range of optimum pH value was 10-11,proper air was needed for the growth,but there was no correlation between the illumination and growth of the fungus.The mediums of carbon souree based on corn powder and soybean powder and nitrogen source on peptone and beef were the most beneficial to the growth of SF-193.Security tests on 86 non-target plant species in 25 families revealed that SF-193 was not pathogenic to the majority plants,especially to crops and vegetables indicating its potential as a biological herbicide against alligator weed.