Disease suppression on greenhouse tomatoes using plant waste compost

This study investigated the disease suppression abilities of a compost amendment that was added to the conventional growing medium, yellow cedar sawdust, used in most British Columbia vegetable greenhouses. The compost amendment was produced in a controlled, in-vessel process primarily from greenhouse crop waste materials. The pathogen and cultivar under study were Fusarium oxysporum f. sp. radicis-lycopersici (FORL) on Dombito (FORL-susceptible) beefsteak greenhouse tomatoes. Significant reduction of Fusarium crown and root rot was also realized in tomato seedlings by applying compost amendment from several different batches, as a seed cover or plug substitute. In a greenhouse trial, disease suppression using a mixture of 2:1 sawdust to amendment by volume was shown to be most effective. As a result, the tomato yield over a nine-month growing season was improved by 74% where the medium was deliberately infested with FORL.