Abstract:To detect bio-safety of Trichoderma REMI (restriction enzyme mediated integration) mutants, spores of Trichoderma REMI mutants were inoculated into seeds, soil and water by means of conventional technics of microbial isolation, biomass determination of plant, etc, its survival in water and its effects on rhizosphere microorganisms and growth of melon, maize, and weeds, as well as toxicity on fish fry were detected. The results showed that the majority of Trichoderma REMI mutants, except Ttrm53, were safe to melon and maize seeds and could increase significantly germination ratio, the number of fibrous roots and improve the growth of melon and maize seedling. Some REMI mutants expressed stronger inhibition to weeds. All tested REMI mutants showed significant effects on the number of fungi in rhizosphere soil of melon, but did not on bacteria and actinomyces. Spores of Trichoderma REMI mutants could not germinate in river and tap water. Conidial spores and chlamydospores could survive in water for 12-18 days and 18-27 days, respectively. Trichoderma REMI mutants were not harmful to the growth of fish fry. Most of Trichoderma REMI mutants were in-noxious.