Abstract:The effects of six fungicides, including carbendazism, thiophanate-methyl, thiram, mancozeb, chlorothalonil and quintozene, three fertilizers, including carbamide (CO(NH2)2), calcium superphosphate (Ca(H2PO4)2·H2O), potassium sulfate (K2SO4), eight micronutrient elements, including copper, zinc, iron, molybdenum, calcium, manganese, magnesium, and potassium, on mycelium growth and sporulation of strain T23 of Trichoderma viride, and on its colonization in rhizosphere of sweet melon were investigated by means of conventional technics of soil microbial isolation, biomass determination of fungi, etc. The results suggested that significant difference of effects of six fungicides, three fertilizers, eight micronutrient elements, and their treated concentrations existed on mycelium growth, sporulation, rhizosphere colonization of strain T23 of Trichoderma viride, respectively. Carbendazism and thiophanate-methyl, carbamide, zinc sulfate and magnesium sulfate exhibited a stronger inhibition to strain T23. At concentration of 20μg/mL, two fungicides, carbendazism, thiophanate-methyl, inhibited mycelium growth of strain T23 on PDA plates by 100.0% and 79.0% respectively. At 21 days after adding, carbamide at 0.23% inhibited the rhizosphere colonization of strain T23 by 35.6%. The inhibition rate of 100mg/L zinc sulfate and 1000mg/L magnesium sulfate on colonization of strain T23 in soil was 31.1% and 15.9%, respectively. Rhizosphere colonization of strain T23 were stimulated by adding some amounts of ammonium, calcium sulfate, potassium dihydrogen phosphate to medium or applying mycozob and potassium sulfate to soil.