GATDULA, MARITES NUESTRO, "Control of Pythium sp, and Phytophthora sp. Infecting Papaya Seedlings Using Trichoderma Activated Compost (TAC)". The effectiveness of Trichoderma activated com-post (TAC) in protecting papaya seedlings from Pythium and Phytophthora infection under greenhouse condition was determined, Moreover, the antagonistic activity of two species of Trichoderma on Enhlum and Phytophthora under laboratory condition was also determined. Incorporating TAC to the soil at levels of 50g, 100g, 150g, 200g, and 250g was found effective to suppress infection by inoculated Pythium Aphanidermatum, Pythium spe (local isolate) and Phytophthora parasitica in papaya seedlings under greenhouse condition. Although insignificant, the germination of papaya seeds were found to be highest at 50g TAC and 100g TAC and lowest of Og, 150g, 200 g, and 250g TAC, This is explained by the presence of pathogens at Og TAC and soil acidity with increased level of organic matter (150g - 250g TAC), Under laboratory condition, the Trichoderma har-zianum and Trichoderma Isonia2ii were most antagonistic to colonies of Pythium aphanidermatum and palm sp, (local isolate)0 However, mycelial growth of these two Pythium isolates were inhibited most by Trichoderma koningii especially after a bright yellow pigment, it produced diffused into the medium. The colony diameter of most pathogen cultures were gradually reduced while some were totally eliminated. The two species of Trichoderma also attempted to antagonize colonies of P. parasitica, however, the latter may seem to withstand the invasion of the former. Nevertheless, the aerial mycelia of P. parasitica was reduced by Trichoderma.