Overall, results from this study showed that bacteria isolated from suppressive compost tea inhibited fungal growth in vitro and disease in vivo. The two most effective bacteria were often found to function in synergy. Antifungal compounds, including surfactins, were found in the bacterial extracts suggesting that antibiosis is a main mechanism of action. However, mode of action involving induction of tomato defense responses may also be involved. Future work will attempt (i) to profile and identify microbial antagonist populations by PCR-DGGE and pyrosequencing in highly suppressive compost teas and (ii) to identify compost tea preparation parameters that enhance populations of these antagonist bacteria as well as (iii) to identify additional antifungal compounds and elucidate their modes of action.